Therapeutic Apheresis in Hematologic, Autoimmune and Dermatologic Diseases With Immunologic Origin
The process of curing a patient by removing his illness by extracting blood is a very old one. Many years ago, phlebotomy was practiced to cure illness. Now, this old process, placed on a rational basis with therapeutic apheresis (TA), is being followed in clinical practice. Therapeutic plasma exchange (TPE) with hollow fiber modules has been used in different severe diseases for more than 40 years. Based on many years of experience with the extracorporeal circulation in end-stage renal disease, the authors herein give an overview of TA in immunological diseases, especially in hematologic, autoimmune and dermatologic diseases. Updated information on immunology and molecular biology of different immunological diseases is discussed in relation to the rationale for apheresis therapy and its place in combination with other modern therapies. With the introduction of novel and effective biologic agents, TA is indicated only in severe cases, such as in rapid progression despite immunosuppressive therapy and/or biologic agents. In mild forms of autoimmune disease, treatment with immunosuppressive therapies and/or biologic agents seems to be sufficient. The prognosis of autoimmune diseases with varying organ manifestations has improved in recent years, due in part to very aggressive therapy schemes. For the immunological diseases that can be treated with TA, the guidelines of the German Working Group of Clinical Nephrology and of the Apheresis Applications Committee of the American Society for Apheresis are cited. TA has been shown to effectively remove the autoantibodies from blood and lead to rapid clinical improvement.
Therapeutic plasma exchange (TPE) was almost exclusively carried out by the centrifugal technique before the development of hollow fiber membranes. Due to new therapeutic strategies, apheresis techniques have experienced a tremendous revival in recent years. TA has been successfully used in various antibody-mediated diseases. More selective plasma separation methods can remove nonspecific immunoglobulins from the patient's blood by new developed adsorbers . Since the pathogenetic relevance of auto-antibodies could be defined in various diseases, disease-specific adsorbers have been developed [2-4]. These adsorbers also remove selective, immune complexes, immunoglobulins, and other substances from the patient's blood.
The term autoimmune disease relates to diseases caused by antibodies acting against the body's own tissue. They are also referred to as autoaggressional diseases. Autoimmune diseases, with exception of rheumatoid arthritis and autoimmune thyroiditis, are individually rare, but together they affect approximately 5% of the population in western countries . The cause of autoimmune reactions is still generally unknown.
Autoantibodies directly cause the destruction of the target cells in lysis. The cytotoxic antibodies react through complement activation with antigens of the cell surface and cause an intravascular lysis of erythrocytes through stages, (e.g., paroxysmal hemoglobulinuremia) particularly in the case of hematological diseases. In autoimmune hemolytic anemia for example, the affected erythrocytes can be opsonized by the antibodies. The process of binding of antibodies with complement participation changes the cells such that they are increasingly phagocytized, whereby the Fc-parts of the bound antibodies are recognized by the Fc-receptors of the phagocytizing cells and by the cells of the RES in the liver and the spleen. The so-called immune clearance is the opsonization process, a physiologically effective way of removing intruding cells through immune bodies .
Inflammation is a complex set of events accompanied by the release of many different soluble antibodies that diffuse away from the side of their production. Autoantibodies can be detected in all tissues and can be directed against many non-hematogenous tissues. Antibodies are transported via efferent lymphatics into the venous and circulate with the blood through the body. Antibodies of the IgG class can transverse blood vessel wall and enter extravascular tissue spaces .
Antibody occupation of cells or tissue structures does not necessarily mean that damage occurs. This only happens when mediators are involved. Autoantibodies can have a serious effect on an organ even without the activation of the complement system, especially when either functionally important receptors are blocked by antibodies or else important proteins are rendered inactive through the combination with antibodies, such as hormones or enzymes. Myasthenia gravis is a classic example of a receptor blockade.
The term immune complex (IC) disease refers to diseases caused by antigen-antibody complexes. The antigen is sometimes of infectious origin. In most cases, however, neither the origin nor the structure of the antigen is clear. IC formation is a physiological process for eliminating foreign material, such as bacteria, their components and viruses. Normally ICs are removed from the blood by adhesion of the Fc-fragments of the antibodies to the corresponding phagocyte receptors in the liver and spleen. If the ICs activate the complement system (immune clearance) phagocytosis can even be enhanced. More than 80% of glomerulonephritis cases are caused by intra renal deposited circulating immune complexes (CIC). If the antigen adheres to the basal membrane and binds circulating antibodies, the IC probably first form in situ .
The authors give an overview of the most important pathogenic aspects indicating that TA can be a supportive therapy in immunological hematologic, autoimmune, and dermatologic disorders.
Therapeutic plasma exchange is indicated in the management of various hematological diseases. For most of these diseases, clear pathogenetic mechanisms of the disease are understood, and there are well-defined criteria with regard to the therapy . Most medical management of immunohematological disorders requires the use of TA, serological immunomodulation, and classical pharmacological immunosuppression with steroids, cytotoxic agents, and antimetabolites, where overall therapy is individually tailored to the needs of the patient. Controlled trials are difficult if not impossible because of variables such as severity of disease, degree of organ system damage before intervention, age and the existence of co-morbid conditions. In some rare hematological diseases, it is impossible to recruit a large number of cases to perform a controlled clinical trial. Therefore, for most of these diseases only small series of cases are available for analysis.
Therapeutic plasma exchange, semi-selective cascade filtration or IA aimed at the causative antibodies can be used in diseases caused by antibodies or immune complexes. Adjuvant drug therapies are different for different diseases and are typically individualized in type, dose and duration of use. The TA method chosen depends on the pathophysiological origin of a given disease. The physician who has chosen the TA method must be knowledgeable concerning the half-life time, the compartmental distribution of pathogenic plasma proteins, and the elimination of other toxic substances and complement components. Table 1 shows a selection of hematological and hemostasiological diseases in which TA has been implemented with the categories and the recommendation grade (RG) from the AAC.
Table 1. Therapeutic apheresis (TA) in hematological and hemostasiological diseases with immunologic origin
|Rhesus incompatibility||TPE||II||2C||1–1.5||Human-albumin-electrolyte solution||Daily or every other day|
|Red cell alloimmunization in pregnancy||III||2C|
|Autoimmune hemolytic anemia|| || || || |
|Warm autoimmune hemolytic disease||TPE||III||2C||1–1.5|
|Cold agglutinin disease||II||2C|
|Pure red cell aplasia||III||1B|
|ABO incompatible HPC Tx||TPE, RBC exchange ECP||II||1B–2B||1-1.5||Human-albumin- electrolyte||Daily or every other day; series weekly|
|Skin (acute)||II||1C||200–270 mL|
|Non skin (acute/chronic)||III||2B|
|Idiopathic thrombocytopenic purpura||TPE, IA-Protein-A||IV||2C||1–1.5||Human-albumin-electrolyte, solution, plasma||Daily or every other day|
|Coagulator factor inhibitors|| || || || |
|Alloantibody||TPE, IA-Protein-A TPE, IA-Protein-A||IV||2C||1–1.5|
Rhesus Disease, Hemolytic Disease in Newborns
Rh disease or incompatibility during pregnancy is an indication for TPE as a supportive therapy . Although it has been common practice for years to carry out anti-D gamma globulin prophylaxis in Rh-negative women after the birth of an Rh-positive child, increased anti-D antibodies still occur in up to 3% of subsequent pregnancies. This can lead to life-threatening morbus hemolyticus neonatorum for the fetus. Newborn babies rapidly develop anemia and hyperbilirubinemia with kernicterus. Exchange transfusion is the therapy of choice. Recently, TA has also become possible . The diagnosis can be quickly made through the detection of anti-D antibodies in the mother and examination of the amniotic fluid for bilirubin and anti-D antibodies. Intrauterine exchange transfusions can be a life saving procedure but involve a high risk. The earlier Rh incompatibility manifests itself in pregnancy, the poorer the prognosis. If it occurs prior to the 26th week of pregnancy, more than 93% of fetuses die by the 31st week. If after the 26th week the Rh incompatibility manifests itself, and the mother receives TPE treatment, and the child receives intrauterine or postpartal exchange transfusion, 71% of these children can survive whereas without treatment most die .
Hemolytic disease in newborns presents as icterus neonatorum or hydrops fetalis. Both are caused by alloimmunization against RhD-positive red blood cells of a RhD-negative mother bearing a RhD-positive fetus. Alloimmunization of the mother occurs after fetomaternal hemorrhage during the first pregnancy. The anti-RhD antibodies, which all belong to IgG subclasses, are able to transverse the placental barrier into the fetal circulation. The antibodies destroy fetal red blood cells by a non-complement-dependent mechanism . Hemolytic disease in newborns usually occurs during the second pregnancy with an RhD-positive fetus. Intravascular fetal transfusion with RhD-negative erythrocytes compatible with the mother's serum is indicated in severe fetal hemolysis in a sensitized mother. After birth the newborn may receive a phototherapy and/or a neonatal exchange transfusion, or TPE, depending on the severity of hemolytic disease in newborns (HDN) .
The widespread use of fetal intravascular transfusion and the advent of IVIg therapy have now reduced the former significance of this disease. Towards the beginning of the second trimester in women who have developed hydrops fetalis before the 22nd week of a previous pregnancy combined with IVIg, TA can be administered . TPE with human albumin may bridge the gap between the onset of severe fetal anemia and the feasibility of fetal transfusion. To save the fetus for alloimmunization against other red cell antigens, which makes fetal intravascular transfusion impossible, maternal TA may be the only therapeutic option. Filbey et al. reported in 1995 of 707 infants born to 583 alloimmunized women in Sweden . Maternal TPE was performed in 2.4% of the cases with a response rate of 100%. TPE is recommended, therefore, only in severe HDN in the early stage of pregnancy before fetal transfusion is possible. TPE has been successfully performed thousands of times in recent years for Rhesus incompatibility. The physician must be aware that anti-D antibodies can also increase with TPE.
In 2006 Bing et al. reported successfully treating 44 pregnant women with Rh incompatibility using a combination of anti-D immunoglobulin and TPE, and intrauterine transfusion. The effects gained from the therapy lasted for approximately 6 weeks for the patients. The study demonstrated that systematic management (including routine test for the presence or absence of D antigen in pregnant women, series test of anti-D antibody titer and ultrasonography, amniocentesis and cordocentesis) and timely treatment (including anti-D immunoglobulin, TPE, intrauterine transfusion, and delivery) can improve the perinatal outcomes of Rh-negative women .
The AAC of the ASFA has given HDN category II or III [7, 8] (Table 1). The rationale for therapeutic apheresis is that TPE removes the maternal red cell alloantibodies that are responsible for HDN . TPE can decrease the maternal antibody titer and, in turn, the amount transferred to the fetus, thereby protecting it from HDN. Survival in severe cases of HDN with the use of TPE and/or IVIg prior to ultrasound tomography (IUT) is about 70%. Category II for TPE is assigned for patients when there is a previous history of a severely affected pregnancy and the fetus is less than 20 weeks gestational age . Typically, IUT can be performed after the fetus reaches 20 weeks of gestation.
Therapeutic plasma exchange can safely be performed during pregnancy. During pregnancy, blood volume and especially the plasma volume increases. In the second or third trimester, it is preferable to place the patient on her left side to avoid compression of the inferior vena cava by the gravid uterus. Hypotension should be avoided as it may result in decreased perfusion to the fetus . TPE should be considered early in pregnancy (from the 7th to 20th week) and continued until IUT can safely be administered (about 20th week of gestation). Close monitoring of the fetus for signs of hydrops will aid in guiding treatment. One approach is to use TPE for the first week (three procedures) followed by IVIg at 1 g/kg weekly .
The etiologies of hemolysis often are categorized as acquired or hereditary. Most acquired causes of hemolytic anemia are autoimmunity, microangiopathy, and infections. Immune-mediated hemolysis, caused by anti-erythrocyte antibodies, can be secondary to malignancies, autoimmune disorders, drugs, and transfusion reactions. When the red cell membrane is damaged in circulation a microangiopathic hemolytic anemia is the consequence, leading to intravascular hemolysis and the appearance of shistocytes. Infectious agents such as malaria and babesiosis invade red blood cells .
The severity of hemolytic anemia is quite variable. Depending on the cause it can be mild and compensated for by increased erythropoiesis. The treatment for mild forms and forms of such severity as to decrease red cell mass is directed at correction of the underlying cause. For example, proper antibiosis and supportive care for infections, surgical debridement and antibiotics for Clostridium welchii, and stopping the offending drugs in the case of G6PD deficiency. In severe hemolytic anemia, with hemoglobinemia, heme saturation of albumin and hemoglobinuria regardless of whether it is mediated by exogenous or endogenous noxae, timely implementation of TPE appears justified .
Autoimmune Hemolytic Anemia (AIHA)
Autoimmune hemolytic diseases are characterized by reduced erythrocyte in vivo survival time and by the presence of warm or cold agglutinizing antibodies against the autologous erythrocytes. Differentiation between the following antibodies is made on the basis of their serological features [12, 13]:
- Thermo-type: Warm agglutination autoantibodies. These autoantibodies consist mostly of IgG and its various subclasses. Optimum antibody binding activitis is reached at body temperature (37 °C).
- Cryo-type: Cold agglutination autoantibodies. These belong to the group of IgM antibodies and display their strongest reaction to antigen-bearing cells at low temperatures (0–10 °C). They become of clinical importance when a temperature of 30 °C or more is reached.
- Bithermal autoantibodies: These belong to the IgG antibodies. Contrary to thermo-type, antibodies bind at low temperature (0–10 °C) and hemolyze erythrocytes at body temperature (37 °C) .
Autoimmune hemolytic anemia is diagnosed by direct microscopic evaluation of the peripheral blood film, hyperbilirubinemia, reticulocytosis, positive direct antiglobulin test (direct Coomb's test), and elevated serum LDH [12, 13]. Immune hemolytic anemia is a result of antibody fixation to a red cell antigen. This autoantibody triggers either intravascular red cell destruction mediated by the terminal lytic complement complex (C5b-C9) or extravacular destruction mediated by macrophage-phagocytic system . Both mechanisms require opsonization by antibodies or C3b complement . The antibodies mostly belong to the IgM (cryo-type abs) and IgG groups, or occasionally also to the IgA (thermo-type abs). The reason for the formation of the autoantibodies is still unknown.
When warm autoantibodies attach to red blood cell surface antigens, these IgG-coated red blood cells are partially ingested by the macrophages of the spleen, leaving microspherocytes, the characteristic cells of AIHA. Cold autoantibodies (IgM) temporarily bind to the red blood cell membrane, can activate complement, and deposit complement factor C3 on the cell surface. The macrophages of the liver (extravascular hemolysis) slowly clear these C3-coated red blood cells .
Although most cases of autoimmune hemolysis are idiopathic, potential causes should always be sought. Lymphoproliferative disorders (e.g., chronic lymphocyte leukemia, non-Hodgkin's lymphoma) may produce warm or cold autoantibodies. A number of commonly prescribed drugs can induce production of both types of antibodies. Warm AIHA (WAIHA) also is associated with autoimmune disease (e.g., systemic lupus erythematosus), while cold AIHA may occur following infections, particularly infectious mononucleosis and Mycoplasma pneumoniae infection. Human immunodeficiency virus infection can induce both warm and cold AIHA [11, 13]. Along with conventional therapy with corticosteroids and cytostatics or even splenoctomy, TA is increasingly being implemented with success .
The AAC of the ASFA has given autoimmune hemolytic anemia category III with RG 2C for the warm autoimmune hemolytic anemia and for the cold agglutinin disease category II with RG 2C [7, 8] (Table 1). The observed symptoms include fatigue and jaundice. The laboratory findings are the signs of hemolysis such as anemia, hyperbilirubinemia, elevated serum LDH, reticulocytosis, as well as a positive direct antiglobulin (Coombs) test .
Antibody removal by TPE is also effective here. Prednisone is usually ineffective, as is splenectomy, because the liver is the dominant site of destruction of C3b-sensitized red cells . TPE can remove effectively pathogenic immune complexes, activated complements, and autoantibodies . The duration of the TPE treatment is until the hemolysis is controlled and the need for transfusions is limited.
Until now only some case reports of aplastic anemia (AA), which have been treated with TPE, have been published. The pathogenesis of aplastic anemia is regarded as complex and mostly unclear. In some cases, hemopoietic and erythropoietic inhibitors have been found in serum, leading to it being considered an autoimmune disease . In these patients it was possible to remove the circulating inhibitors by TPE. TPE is only indicated in the case of proven autoimmune pathogenesis. Successful therapy has also been conducted in recent years with cyclosporin A.
The AAC of ASFA has given aplastic anemia and pure red cell aplasia (PRCA) category III with RG 2C [7, 8, 17] (Table 1). Aplastic anemia and pure red cell aplasia are rare hematopoietic stem cell disorders.
Allogenic hematopoietic progenitor cell (HPC) transplant is the treatment of choice for severe AA in newly diagnosed patients < 40 years old. Young patients with mild disease or without a matched donor and older patients are treated with antithymocyte globulin (ATG), cyclosporine A and/or rituximab [18, 19]. Immunosuppressive therapy is usually sufficient until remission is obtained in primary acquired PRCA. Corticosteroids (prednisone at 1 mg/kg per day) are used first. Alternative treatment is required if no response is achieved after 2–3 months. Salvage agents include cyclophosphamide, azathioprine, cyclosporine, ATG, and high-dose IVIg . In diseases that may be immunologically mediated, TPE may be helpful by removing serum antibody and/or inhibitory activity.
ABO Incompatible Hematopoietic Progenitor Cell Transplantation
The presence of natural antibodies in the recipient against the donor's ABO blood group, which may cause hemolysis of red cells present in the transplanted product, is the requirement of the major incompatibility . In peripheral hematopoietic progenitor cells that are collected by apheresis, there is a lower risk of hemolysis due to reduced red cell contamination (2–5%) as compared to HPCs derived from the bone marrow. To prevent an acute hemolytic reaction either the product needs to be red cell reduced or the patient's antibody titer needs to be lowered. If the recipient has a high titer of antibodies, especially a group O patient receiving a group A transplant, a delayed erythroid engraftment or even pure red cell aplasia may result .
The AAC of the ASFA has given category II with RG 1B–2B for TPE in ABO incompatible hematopoietic progenitor cell transplantation and bone marrow transplants [7, 8] (Table 1). TPE can reduce ABO antibodies, which are responsible for hemolysis and PRCA. In most of the ABO incompatibility, removal of the high titer antibody from the recipient's circulation can prevent hemolysis if red cells are unable to deplete the product.
In minor incompatibility with passenger lymphocytes making antibodies 7–12 days after infusions, prophylactic red cell exchange with group O red cells can be performed to deplete recipient type red cells [7, 8]. If unable to red cell deplete the HPC product, TPE should be performed before infusion of HPCs and the replacement fluid is a combination of albumin and plasma (50:50) compatible with both donor and recipient . Before HPC transplantation, the goal should be to reduce the IgM or IgG antibody titers to ≤ 1:16 immediately. Generally, 2–4 TPEs are sufficient and if the antibody titer is high in the case of delayed red cell recovery or PRCA, TPE may be performed in the transplantation period .
The graft-versus-host disease (GVHD) has category II with RG 1B–2C for acute or chronic skin, and III with RG 2B for acute or chronic non-skin for extracorporeal photopheresis (ECP) after the AAC of the ASFA [7, 8] (Table 1). GVHD following allogenic progenitor cell transplantation (HPCT) is typically characterized as either acute (aGVHD) or chronic (cGVHD) . Acute GVHD usually occurs within 3 months after allogenic stem cell transplantation (HPCT) and results from activation of donor T cells by host antigen-presenting cells, leading to immune and cytokine-mediated tissue injury. The skin, gastrointestinal tract, and liver are major targets of aGVHD. Chronic GVHD often evolves from aGVHD and is mediated by donor allo- or autoreactive T cells that activate inflammatory cytokines, B cells, autoantibody production, and cytolytic process. End-organ complications of cGVHD include progressive fibrosis and/or dysfunction of the skin, eyes, mouth, lungs, gastrointestinal tract (GI), joints, and vagina [7, 8]. Acute GVHD of grades II to IV severity is first treated with a calcineurin inhibitor and systemic corticosteroids. Treatment options include local/topical measures for the skin, eyes, mouth, and gastrointestinal tract along with systemic therapies such as calcineurin inhibitors, ATG, mycophenolate mofetil, rapamycin, thalidomide, hydroxychloroquine, sirolimus, pentostatin, monoclonal antibodies against T cells, B cells or cytokines, and ECP .
The rationale of extracorporeal photopheresis involves the collection of peripheral blood leukocytes by apheresis, the extracorporeal exposure of the leukocytes to 8-methoxypsoralen (8-MOP) followed by irradiation with ultraviolet A (UVA) light, and the reinfusion of the photactivated cells .
The therapeutic effect of ECP for GVHD appears to involve induction of apotosis in treated lymphocytes, modulation of monocytes-derived dendritic cell (DC) differentiation, increased production of anti-inflammatory cytokines by monocytes and T cells, decreased DC antigen-presenting function, restoration of normal T helper cell and DC subsets and induction of regulatory T cells that establish immune tolerance. For cGVHD, ECP improves skin or oral manifestations in 60–80% of steroid-dependant patients. Liver or GI complications respond in roughly 35–75% of cases, with the highest rates reported in children. Most responses with cGVHD are partial [7, 8].
The treated volume is a mononuclear cell (MNC) product of approximately 270 mL consisting of mononuclear cells, plasma and saline . The two-process method collects and treats MNC obtained from two times TPV processing. The replacement fluid is that all photoactivated leukocytes are reinfused with albumin and saline.
Idiopathic Thrombocytopenic Purpura
Thrombocytopenia is an inherited or acquired disease that results in a reduction of circulating thrombocytes. This condition may be asymptomatic or manifests itself in hemorrhagic diathesis with petechial bleeding. The immune thrombocytopenias are a heterogenous group of bleeding disorders with similar hemostatic manifestations but different pathogenic etiologies.
Idiopathic thrombocytopenic purpura (ITP) is caused by autoantibodies which, in severely progressing cases, are accompanied by hemorrhagic diathesis. ITP is the most common autoimmune hematologic disorder. The etiology is still for the most part unknown. The spleen plays an important role, since it not only produces a large part of the antibodies directed against thrombocytes, but also breaks down the damaged thrombocytes. As the antibodies can pass through the placenta barrier, the fetus can also be affected . In more than 60% of the patients, part or full remission can be reached with steroid therapy. Splenectomy and cytostatics are further therapeutic measures. In recent years, in addition to being treated with TPE , therapy-resistant, acute, and chronic cases have also been successfully treated with high doses of intravenous immunoglobulin of 400 mg/kg BW/day. The pathophysiological mechanism in ITP is the binding of auto- or alloantibodies to platelet antigens. Fixed antibodies may trigger complement activation . The opsonized platelets are destroyed by phagocytosis in the macrophage-phagocytic system mediated by the Fc receptors FcγRI-III and complement receptors CR1 and, CR3. Platelet destruction occurs mainly in the spleen (and accessory spleen), but also in liver and bone marrow . The spleen is a major site of antiplatelet antibody production; therefore, splenectomy is therapeutically very effective. The main antigenic determinants are the platelet membrane glycoproteins GP-Iib/IIIa and Ib/IX .
A further mechanism leading to platelet destruction in drug-induced immune thrombocytopenic purpura is the formation of antibodies against neoantigens expressed after adherence of the drug to the RBC membrane . Recently, acquired autoimmune deficiency of a plasma metalloprotease named ADAMTSJB was shown in many cases of ITP . Alloimmunization is the cause of neonatal alloimmune thrombocytopenia, platelet transfusion refractoriness, and post-transplant purpura. The alloantigens are classified in the human platelet antigen (HPA) system . Neonatal immune thrombocytopenia is the platelet counterpart of hemolytic disease in newborns. A HPA-1a-negative mother is sensitized to HPA-1-positive platelets of the fetus. Alloimmunization (IgG ab > IgM ab) against platelets induced by fetomaternal hemorrhage occurs during an HPA-incompatible pregnancy or after a HPA-incompatible platelet transfusion. In heparin-induced thrombocytopenia, type II immune complexes consisting of antibodies to heparin and platelet Factor 4 activate platelets after binding to platelet Fc receptors. Excess platelet Factor 4 binds to endothelial glycosaminoglycan, resulting in endothelial damage and thrombosis . Heparin-induced thrombocytopenia type I refers to non-immunogenic thrombopenia due to heparin-induced aggregation of platelets.
Acute abrupt onset ITP is seen in childhood, and often follows a viral illness or immunization. The majority of children require no treatment and in 80–85% of cases the disorder resolves within 6 months. Some 15–20% of children develop a chronic form of ITP, which, in some cases, resembles the more typical adult disease. Chronic ITP in childhood has an estimated incidence of 0.46 per 100 000 children per year and prevalence of 4.6 per 100 000 children at any one time [7, 29]. This form of ITP affects mainly women of childhood age (female: male: 3:1). Childhood ITP has an incidence of between 4.0 and 5.3 per 100 000 .
The diagnosis of ITP based principally on blood count, clinical symptoms, autoimmune profile and other investigations, and on the exclusion of other causes of thrombocytopenia using the history, physical examination. Further investigations are not indicated, blood count and film are typical of the diagnosis of ITP and do not include unusual features that are uncommon in ITP . Platelet associated IgG (PAIg) is elevated in both immune and non-immune thrombocytopenia and therefore has no role in the diagnosis of uncomplicated ITP. In patients refractory to therapy although some patients have shown improvement in platelet counts following eradication therapy, it is worth determining the presence of H. pylori . The first-line therapy comprises oral corticosteroids and intravenous immunoglobulins.
The successful use of high doses of IgG and anti-D therapy has reduced TA to second-line or third-line treatment in these cases . The second-line therapy is splenectomy and high dose corticosteroids, high dose IVIg, intravenous anti-D, cyclosporin A and dapsone. Patients who failed the first- and second-line therapies must be treated with interferon-α (IFNα), rituximab, campath-1H, mycophenolate mofetil and TA . TA can induce remissions in approximately 80% of patients with ITP. TA becomes a legitimate option for maintenance therapy in chronic ITP patients, if the application of IgG is not possible due to allergic reactions, Rh-negative status, or splenectomy.
The most important part of TA is to remove antiplatelet antibodies to prevent bleeding by keeping the platelet count above a critical level. The goal of therapy is to obtain sustained remission with a minimum platelet count of over 50 000 platelets/μL. The measurement of free antiplatelet autoantibodies is a useful test for determining whether TA is indicated and if so, to assess its efficacy. As some severely progressing cases of ITP do not respond to steroids and/or high doses of immunoglobulin, immunosuppresive drugs, TPE is indicated .
As there are only a few controlled studies yet available, it is not possible to reliably conclude which form of therapy should be given preference. Thus, in ITP, initial treatment should consist of high doses of IgG, and immunosuppressive drugs as mentioned above. Should no significant improvement be observed within one or two weeks (thrombocytes > 80 000/μL), then TA treatment should be commenced immediately. The authors recommend plasma exchange with 1 to 1.5 plasma volumes a day for 4 days. Treatment with two to four sessions of TPE per month can also have a positive effect in chronic cases. TPE is recommended prior to surgery in acute respectively chronic uncontrollable bleeding . Immunoadsorption with Protein-A was also introduced successfully in the treatment of ITP.
In the guidelines on the use of TA of the ASFA, ITP has category III for IA in refractory cases and category IV for TPE.  (Table 1). First-line therapies are oral corticosteroids, IVIg (1–2 mg of prednisone/kg per day, IVIg at 1 g/kg per day for 1–2 days), and IV anti-Rh (D) (50–75 µg/kg) . If thrombocytopenia persists or recurs, splenectomy is recommended in adults but is deferred to prevent overwhelming postsplenectomy infection or allow for spontaneous remission. TPE and IA with Protein-A columns may be considered in patients with refractory ITP, with life-threatening bleeding or in whom splenectomy is contraindicated . IgG antibodies and IgG-containing circulating immune complexes can be selectively removed by IA with protein-A. The use of this column is contraindicated when the patient is on ACE inhibitors, has a history of hypercoagulability, or thromboembolic events . There are no clear guidelines concerning treatment schedule and duration of treatment. The procedure is generally discontinued when either the patient shows improvement in platelet count > 50 × 109/ L or no improvement after about six treatments. The columns with protein-A are no longer available in the United States but may be available in other countries .
Post-transfusion purpura (PTP) occurs when donor B lymphocytes and dendritic cells migrated as passenger cells to the recipient's system, where they undergo clonal expansion after “homing in” on, and producing alloantibodies to the incompatible HPA allele . Post-transfusion purpura is a rare bleeding disorder caused by alloantibody specific to platelet antigens. The antibody against the human platelet alloantigen HPA-1a is responsible for most of the cases: The majority of affected patients are multiparous women who presumably have been previously sensitized during pregnancy . Blood transfusions rarely have been implicated as the primary cause for alloimmunization in PTP. Thrombocytopenia is usually severe and resolves spontaneously within several weeks. However, patients may develop severe if not fatal bleeding during the course of the disease. The diagnosis is confirmed by demonstrating that the patient's serum contains antibodies to platelet-specific antigens. Treatments for PTP include intravenous immunoglobulin, corticosteroids, and TPE .
The treatment is high IVIg (0.4 g/kg BW/day for 2–5 days or 1 g/kg BW/day for 2 days) . It possibly acts by Fc receptor blockade of reticuloendothelial system. The removal of HPA-1a alloantibodies by TPE results in a decrease of antibody titer, removal of any unattached HPA-1a antigen, and an increase in platelet count and cessation of bleeding. TPE should be considered as the urgent treatment of hemorrhage and severe thrombocytopenia if IVIg therapy is not effective . In the guidelines on the use of TA of the ASFA the PTP has category III with RG 2C for TPE based on limited data available in the literature [7, 8] (Table 1). TPE can be discontinued when platelet count starts increasing (>20 × 109/L) and non-cutaneous bleeding stops .
This is a defect of the endogenous coagulation system, either inherited or acquired. It includes diseases that result from reduction, lack, or malformation of the factors VIII, IX, XI, XII, or prekallikrein. Hemophilia A is the longest-known hemorrhagic diathesis. As a result of substitution therapy, 5–20% of hemophiliacs develop antibodies against factor VIII administered during the course of treatment. Factor VIII antibodies belong to the IgG immunoglobulin group [34, 35]. Antibodies can, however, also occur spontaneously in older patients or after pregnancy. These are antibodies that are directed against the patient's own factor VIII and can lead to an acquired factor VIII deficiency. Hemophiliacs may become sensitized to concentrates of their deficient coagulation factors. This occurs in about 15% of hemophilic patients. Low and high responders can be distinguished. The activity of the inhibitor can be measured in Bethesda units (BM) or Malmö inhibitor units (MiU). The F VIII inhibitors are IgG subclass 4 antibodies. F VIII inhibitors are the most common pathogenic antibodies directed against the blood coagulation factors. They develop in approximately 30% of patients with severe and moderately severe hemophilia A in response to infusions of F VIII. Patients develop inhibitors usually within the first year of treatment. The mechanisms underlying the state of apparent immune tolerance in the remaining non-inhibitor patients are unknown. The greatest risk of inhibitor development is associated with nonsense mutations, large deletions and intrachromosomal recombinations (inversion) in the F VIII gene that are predicted to cause a complete lack of endogenous F VIII. The risk of inhibitor development in patients with mild hemophilia A increases with the amount of exposure F VIII .
Many patients with antibody formation display a rapid increase in antibodies after administration of factor VIII. Attempts to suppress the formation of antibodies in these patients through immunosuppressive therapy have, for the most part, been unsuccessful. TA is used to reduce these antibodies prior to infusing factor VIII. TA in combination with factor VIII has been successful in interrupting severe bleeding in hemophilics who are unresponsive to Factor VIII and as hematologic preparation to normalize these inhibitors prior to major surgery .
TA is indicated in severely bleeding patients classified as immunological high responders . TA can be considered when plasma concentration of the inhibitors exceeds either 10 BM or 3 MiU. TA should be implemented prior to high-dose administration of human VIII concentrates. The use of IA with anti-immunoglobulin columns may be safer and more effective. A further indication for TA is in cases where inhibitors occur after factor substitution to induce immune tolerance according to the Malmö or similar protocols. Serial TPE and simultaneous administration of factor VIII/IX concentrates, high-dose IgG (0.4 g/kg per day), and cyclophosphamide is recommended. This protocol has a success rate of 80%. Chronic immunosuppression may be necessary in some cases .
IA is being increasingly applied in the treatment of F VIII inhibitors. Several types of IA methods have been used, although reports are mainly anecdotal, consisting of relatively small numbers of patients. But IA may be clinically effective and cost-effective and should be considered early in the treatment of patients  (Table 1).
Acquired Factor VIII (F VIII) Antibodies in Non-Hemophiliac Patients
Antibodies against factor VIII can occur in many diseases such as immunological diseases, after pregnancy, as a reaction to medication (e.g., phenylbutazone), skin complaints, tumors, and diabetes mellitus. In the case of most patients with acquired factor VIII antibodies, it is not possible to determine the cause. If the underlying disease is known and treated, a drop in antibody titer can be expected.
F VIII autoantibodies in non-hemophiliacs produce a condition sometimes called acquired hemophilia A. It is the most common autoimmune bleeding disorder involving the coagulation system. For unknown reasons, acquired hemophilia A patients are more likely to have a more severe bleeding diathesis than hemophilia A inhibitor patients. Approximately 50% of acquired hemophilia A patients have underlying conditions, including autoimmune disorders, malignancy, and pregnancy . The remaining idiopathic cases most commonly occur in elderly patients of either sex.
Treatment of bleeding episodes for patients with acquired hemophilia A or congenital hemophilia A with inhibitors depends on the inhibitor titer. Low-titer inhibitors can be overwhelmed with F VIII bypassing agents (prothrombin complex concentrates, activated prothrombin complex concentrates), or recombinant F VIIa or porcine F VIII concentrates can be used to treat patients with high-titer inhibitors. Recombinant F VIIa is effective in controlling most bleeding episodes. There have been no reports of inhibitory antibodies developing to the product .
Acute bleeding complications are an indication not only for the application of highly dosed concentrated factor VIII, but also for the removal of circulating antibodies through TPE. Substitution with fresh frozen plasma also includes the administration of factor VIII. The advantage of TPE and IA is in its rapid removal of antibodies and absence of excessive antibody formation. A disadvantage is an increased risk of bleeding with TPE treatment, if anticoagulation becomes necessary. With IA a selective elimination of acquired factor VIII antibodies is available .
In the ASFA guidelines on the use of TA, the coagulation factor inhibitors in hemophilia A and acquired factor antibodies in non-hemophilia patients has category III with RG 2B for IA and IV with RG 2C for TPE [7, 8] (Table 1). Factor deficiency can either be congenital or acquired; the majority of acquired deficiencies result from autoantibodies. In addition, congenital factor deficient patients can develop inhibitors, allo-antibodies, to the factors. The treatment options for inhibitor suppression include high dose corticosteroids, cyclophosphamide, cyclosporin, rituximab, and high dose IVIg . For coagulation factor inhibitors, the extracorporeal removal by immunoadsorption is more effective than TPE .
The terms “systemic autoimmune disease” and “collagen vascular disease” describe a number of illnesses, the common characteristic of which is immune-mediated destruction of intracellular structures in connective tissue, resulting in fibrinoid tissue damage . Based on an immune pathogenesis, the various organs form antigen components, which provoke formation of autoantibodies on the one hand, and circulating immune complexes causing inflammation in organ tissues on the other.
Antinuclear antibodies are to be found against most nuclear structures. The antibodies are typically directed against both cytoplasmic-associated and cell membrane-associated proteins, and also antibodies against cytoplasmic structures and cell membrane components. The different groups of antibodies observed in active and subclinical disease includes those against many extracellular antigens, such as collagen, myelin sheaths, immunoglobulins, basement membrane, intercellular bridges, hormones, and complement components .
Systemic lupus erythematosus
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by hypergammaglobulinemia, the presence of various autoantibodies, and immunoregulatory alteration. Among the autoantibodies, anti-double-stranded (ds) DNA is highly specific for the disease and is thought to play an important role in its pathogenesis. Anti-ds DNA autoantibodies constitute a heterogeneous family with respect to avidity, cationic charge, immunoglobulin class, and complement-fixing ability .
Systemic lupus erythematosus usually involves high-titer antinuclear antibodies of the IgG group. This antinuclear antibody group includes not only the anti-dsDNA antibodies but also autoantibodies against single-stranded DNA (ssDNA), histones (H1–H4), and non-histone proteins (e.g., Sm, nRNP, SS-A/Ro, SS-B/La) . Thus, in addition to antinuclear antibodies, SLE patients possess, although less frequently, autoantibodies against cytoplasmic antigens (SS-A/Ro, SS-B/La, ribosomes, Golgi apparatus), phospholipids (e.g., cardiolipin), cytoskeletal proteins (e.g., cytokeratin, desmin, vimentin, neurofilaments), basement membrane, and various cell superior determinants of leukocytes, erythrocytes, and thrombocytes.
Most antibodies belong to the so-called easy antigens, i.e., they are long-chained structures with repetitive epitopes, such as DNA, RNA-cell surface antibody, and basement membrane [1, 42]. Many of these antibodies are polyreactive, i.e., show overlapping binding specificity for several antigens. The cause for the polyreactivity of anti-DNA antibodies is thought to be related to the fact that the various antigens have in common certain phosphate remains in a similar conformation or that the antigen binding site of autoantibodies has various independent binding sites .
It is still unclear whether formation of antinuclear antibodies is due to altered (and thus immunogenic) DNA, polyclonal activation of B cells, cross-reaction with bacterial antigens, or a genetically induced disorder of immune regulation. The importance of genetic factors is not only underscored by the abovementioned relationship between human leukocytes and antibodies, but also by recent immunologic analyses of anti-DNA autoantibodies in mice and humans. Natural CD4+ CD25+ regulatory T cells (Tregs) have a potent immunosuppressive function and contribute to immunologic self-tolerance by suppressing potentially autoreactive T cells. Depletion of these cells leads to destruction of severe autoimmune diseases in animal models; more recently, there have been studies reporting impairment of Treg numbers and/or function in various human autoimmune diseases .
The tissue damage is caused by deposition of circulating immune complexes in various organs. Primarily involved are the smaller and medium-sized arteries of the skin, joints, lungs, liver, brain, kidneys, glomeruli, peritubular renal capillaries, and epidermal basement membrane .
Systemic lupus erythematosus is a chronic inflammatory disorder. With its extremely variable range of symptoms, SLE can cause broadly varying clinical conditions, ranging from an acute attack with high temperature, anemia, leukopenia and thrombocytopenia, arthritis, exanthema, and polyserositis, to lasting isolated damage to the kidneys, bone marrow, and joints. The disease preferentially affects childbearing age females (ratio F:M 10:1) . The course of SLE is often unpredictable, with many attacks and milder forms of SLE showing spontaneous remission. Renal involvement in SLE is associated with high mortality. With aggressive therapeutic schemes, survival rates have been steadily increasing in recent years. The American Rheumatology Association compiled the seven most important diagnostic criteria for SLE .
Systemic lupus erythematosus involves increased production of autoantibodies, immune complex deposition in the microvasculature of various organs, complement activation, leukocyte infiltration, and tissue damage. The immune complex glomerulonephritis of SLE is a major cause of morbidity and a determinant of the outcome of the disease . Advances are needed in the treatment of severe lupus erythematosus, both to reduce the current mortality rate of 10–20% after 10 years and to decrease the development of renal insufficiency requiring dialysis, which occurs in nearly one quarter of patients. Also, efforts must continue to minimize the adverse effects of long-term immunosuppressive therapy . Table 2 shows the use of TA in SLE.
Table 2. Therapeutic apheresis (TA) in systemic lupus erythematosus, catastrophic antiphospholipid syndrome, and rheumatoid arthritis
|Systemic lupus erythematosus (severe)||IA, Peptid-GAM, Tryptophan, Dextran sulfate||III||B||TPE||II||2C||1-1.5||Human- albumin- electrolyte solution||Daily or every other day|
|Catastrophic antiphospholipid syndrome||III||C||TPE||III||2C|
|Rheumatoid arthritis||IA, Peptid-GAM||Ib||A||IA||II||2A|
TPE is particularly indicated in severe cases, such as:
- Rapid progression despite immunosuppressive therapy
- Renal involvement, e.g., proliferative glomerulonephritis and nephrotic syndrome [47, 48]
- Extremely acute generalized vasculitis 
- Thrombocytopenia and leukopenia
- Pulmonary, cardiac, and cerebral involvement
- Pancreatitis .
Prolonged treatments have been reported, but their rationale and efficacy are questionable . According to Clark et al., TPE with 4 L once per month probably modulates the immune response and thus intervenes beneficially in the course of the disease . This observation is also confirmed by many years of experience by Bambauer et al.
Cyclosporin is a well known immunosuppressive drug that has been used successfully for many years to delay organ transplant rejection in particular. Cyclosporin A seems to be promising in the management of autoimmune diseases, and via a similar mechanism of immune suppression as observed in animal experiments and in vitro studies. Routine implementation of cyclosporin A in chronic SLE presents new therapeutic possibilities due to selective inhibition of T cell activity at a very early stage . The prognosis for SLE with varying organ manifestations has been considerably improved in recent years due in part to very aggressive therapy schemes .
Antiphospholipid syndrome (APS) is an autoimmune hypercoaguable state caused by antibodies against cell membrane phospholipids that provoke thrombosis in the arteries and veins. Antiphospholipid antibodies can be detected by measuring lupus anticoagulant and anticardiolipin antibodies . Antiphospholipid antibodies are implicated in vascular thrombosis, thrombocytopenia, and recurrent fetal loss in patients with SLE. The etiology of thrombosis of the small and large vessels is not completely understood. Involvement of the kidneys in APS is possible. In addition to thrombosis of the great arteries and veins, microscopic thrombotic microangiopathy is typically observed on kidney histology. High levels of antiphospholipid antibodies in patients with SLE increase the risk of venous and arterial thrombosis, adverse cerebrovascular events, recurrent fetal loss, and other arterial thrombotic and embolic complications, such as superior mesenteric artery thrombosis and thrombocytopenia. While APS can exist without SLE, it should also be considered in non-SLE patients when classical symptoms, such as recurrent thrombosis of unknown etiology, are present. TA can be considered life-saving in patients with severe APS .
Catastrophic antiphospholipid syndrome (CAPS) is an acquired hypercoagulable state, an unusual variant of APS. CAPS is defined as the acute onset of multiple thrombosis in at least three organ systems over a period of days or weeks, in patients with serologic evidence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies, and/or anti-β2 glycoprotein I). The most commonly affected sites are small vessels of kidneys, lungs, brain, heart, and skin, although large vessel thrombosis can also be present .
The exact mechanism by which TPE exerts an effect in CAPS is not known, but removal of pathologic antiphospholipid antibodies, as well as cytokines, tumor necrosis factor-α (TNF-α), and complement, is thought to play an important role. In most reports in which the replacement fluid transfusion of natural anticoagulants such as protein C, protein S, and antithrombin is given, this may contribute to the overall benefit of this procedure. However, it has not been established if plasma transfusion alone would have similar benefits because this option has not been tested. The category III for TPE is assigned based on a paucity of data (Table 2) .
The optimal treatment of CAPS is still debatable given that the condition is rare and there have been no relevant prospective studies. However, the therapeutic approach has to have three aims:
- To treat any precipitating factors, e.g., infection, organ necrosis
- To prevent and to control ongoing thrombosis
- To suppress excessive cytokine production .
Espinosa and Cervera concluded that first-line therapies from retrospective study data should always include the combination of anticoagulation against thrombosis, glucocorticoids plus TA, and/or intravenous immunoglobulins in the treatment of CAPS .
If CAPS is associated with a flare of SLE, cyclophosphamide is also used. In combination with infection parenteral antibiotics should be administered . A minimum of 3–5 TPEs are recommended. Discontinuation is based on the patient's clinical response. Some patients have been treated for weeks.
TPE and IA are valuable treatment strategies in patients with refractory disease manifestations and in pregnancy. IA seems to have a favorable side-effect spectrum compared to TPE. There is a clear need to perform randomized controlled trial to evaluate efficacy, safety and tolerability of both treatment strategies in the treatment of SLE and CAPS [53, 54].
Rheumatoid arthritis (RA) is an autoimmune disease that affects approximately 1–3% of the population and results in considerable morbidity and debility . A typical characteristic of rheumatoid arthritis is that the joints are affected, with accompanying extra-articular manifestations, such as vasculitis as well as spleen and lymph node involvement. Recent evidence supports a central role for activated T cells in its pathogenesis. In the inflamed joints of patients with rheumatoid arthritis, activated T lymphocytes accumulate as activated cells . The etiology and pathogenesis of rheumatoid arthritis are still unclear for the most part. It is known that treatment of this disease is very difficult and even controversial. Most drugs have only limited efficacy.
In RA, which is a chronic multisystem autoimmune disease, the most characteristic feature is an inflammatory synovitis, it can be relapsing or persistent, usually involving peripheral joints in a symmetric distribution. In about 20% of the patients, there are extra-articular features, too. The role of antibodies to cyclic citrullinated peptides in the pathogenesis and diagnosis has been increasing attention .
A positive rheumatoid factor can be serologically detected in about 80% of patients; antinuclear antibodies, circulating immune complexes, cryoglobulins, and hypergammaglobulins may also be present. The rheumatoid factors belong to the IgM and IgG group. The immune complexes can activate the complement system and, via subsequent activation of mononuclear and polymorphonuclear cells, cause tissue damage through release of proinflammatory cytokines, particularly TNF . RA has significant systemic effects, with associated morbidity and mortality. The role of humoral versus immune activity in the resulting disease process is not completely understood. T cells are activated by an unknown initiating process, resulting in production of interleukin-1 and TNF-α, which have been shown to have a significant role in the inflammatory process. It is believed that autoantigens develop after initiation, perpetuating T cell activity and the disease process .
The goals of therapy for rheumatoid arthritis are: relief of pain; reduction of inflammation; protection of articular structures; maintenance of function; control of systemic involvement; healing of bone erosions.
None of the current therapeutic interventions is curative, and all must be viewed as palliative, aimed primarily at relieving the signs and symptoms of the disease . Medical management of RA can be divided conveniently into five groups of medications: Aspirin, other nonsteroidal anti-inflammatory drugs, and simple analgesics; low-dose oral glucocorticoids; disease-modifying antirheumatic drugs (e.g., methotrexate); cytokine-neutralizing agents (i.e., anti-TNF, anti-IL-1); immunosuppressive, and cytotoxic drugs, and novel and effective biologic agents like rituximab .
Because both cellular and humoral mechanisms are involved in the pathogenesis of rheumatoid arthritis, in recent years TPE, cryofiltration, lymphoplasmapheresis, and leukocytapheresis have been implemented in addition to immunosuppressive therapy in particularly severe cases [57-59]. The clinical results of cryofiltration, double filtration, IA, and leukocytapheresis are very encouraging; these methods could be a regular therapy for rheumatoid arthritis, particularly in those patients with poorly controlled disease on immune suppressive or anti-TNF therapy [60, 61].
After the guidelines of the AAC of the ASFA, RA has for immunoadsorption with protein A category II, (Table 2) . The rationale for using staphylococcal protein A column is that protein A has a high affinity for Fc portion of IgG and for high molecular weight IgG and IGM complexes . IgG antibodies and CICs can be selectively removed from the blood by perfusion of patient plasma through the columns. The removal or alteration of CICs by IA, could be immunomodulatory and potentially beneficial for patients with RA. Only small amounts of immunoglobulin are removed by IA (1–3% of total serum Igs) and their concentration is unchanged, as are plasma levels of CICs. An indirect immunomodulatory mechanism is suggested in IA-induced therapeutic responses in RA . The usual treatment course is 12 weeks. In most studies, clinical improvement was delayed for up to a few weeks after completing the procedures.
The current management and treatment of rheumatoid arthritis is first to use the abovementioned five groups of medications with aspirin and other nonsteroidal anti-inflammatory drugs, and lastly, immunosuppressive and cytotoxic drugs. A new class of drugs the biological agents can be used to target specific cells and cytokines. These drugs have been shown to reduce inflammation significantly and to retard the progression of joint damage in rheumatoid arthritis, thereby reducing symptoms and improving function . Early clinical results of monotherapy using tocilizumab, anti-interleukin-6 receptor antibody, in rheumatoid arthritis were excellent . Therefore, TA is only indicated in severe cases of rheumatoid arthritis if all five groups of drugs have failed. The excellent results mentioned previously may be one reason why production of Staphylococcal protein A agarose (Immunosorba; Fresenius HemoCare GmbH, Germany, Germany) and Staphylococcal A silica (Prosorba; Fresenius HemoCare GmbH) columns was discontinued in the United States in December 2006. However, these devices are available in other countries .
Inflammatory eye disease
When conventional therapy with cortisone or immunosuppressive drugs fails or is inadequate in the treatment of immune-mediated inflammatory eye disease with an auto immunologic pathogenesis, TA may be indicated and is increasingly being implemented with success.
Severe uveitis is potentially associated with visual impairment or blindness in young patients . In posterior uveitis, progredient inflammatory processes can lead to morphologic changes in the chorioidea and retina, contributing to functional deterioration. In uveitis intermedia, inflammatory processes in the peripheral retina and in the area of the ciliary body require primary attention and aggressive treatment. In both cases, secondary destructive changes in the vessels can occur, causing reduced perfusion of the retina and chorioidea. Primary inflammatory vascular changes may lead to secondary morphologic chorioretinal changes, which may then further impair function. The inflammatory process and/or the reduced chorioretinal perfusion are important. Therefore, an anti-inflammatory/immunomodulatory therapy, a hemorheologic therapy, or a combination of both treatments, should bring about improvement of the condition, insofar as no other specific therapy is indicated .
Detection of immune complexes or autoantibodies in uveitis is problematic. First, indications for the existence and possible pathomechanism of pathogenic substrates to retinal S antigen were found in patients with uveitis and in animal studies. Both improvement and deterioration in the condition can be regarded as an indication of elimination of a pathogenic substrate.
The improvement in hemorheologic parameters could contribute considerably to the therapeutic success in autoimmune eye diseases accompanied by primary or secondary vascular changes. With improved microcirculation, the damaged tissue can recover. In addition, other mechanisms, such as elimination of a pathogenic substrate or immunomodulatory effects of the exchange medium, probably contribute to the success of this therapy. The immunomodulating mechanism of TA, which favors a prompter elimination of inflammation, increases ocular function, and reduces recurrence, has been clarified.
In recent years, the anti-TNF-α antibodies, infliximab and adalimumab, and others demonstrated significant efficacy in controlling uveitis associated with seronegative spondyloarthropathies and juvenile idiopathic arthritis . The majority of reports of biologic therapies in posterior uveitis have been uncontrolled or retrospective studies in patients with uveitis resistant to immunosuppression.
Biologic therapies have increased the treatment options for sight-threatening uveitis. Despite an experimental rationale, the lack of evidence from randomized controlled studies limits our understanding of when to commence therapy, which agent to choose, and how long to continue treatment. Additionally, the high cost and potential side-effects of the biologic agents have limited their current use to uveitis refractory to immunosuppression. Further controlled randomized multicenter studies of TPE and/or immunosuppression versus biologics are necessary to clarify efficacy, side-effects, and costs.
Dermatologic immune mediated diseases represent a heterogenous group of disorders associated with circulating autoantibodies against distinct adhesion molecules of the skin and/or mucosa. According to the level of split formation, the disorders can be divided in the intraepidermal blistering pemphigus, such as pemphigus vulgaris (PV), pemphigus foliaceus, and paraneoplastic pemphigus, and the subepidermal blistering pemphigoid diseases, such as bullous pemphigoid (BP), pemphigoid gestations, and dermatitis herpetiformis . The new developed sensitive and specific assays for circulating autoantibodies in these dermatological diseases now enable a serological diagnosis in about 90% of cases.
The incidences of autoimmune blistering skin diseases in Germany has doubled in the last 10 years, to about 25 new cases per million humans per year, because of improved diagnostic techniques as well as the aging of the population . There are an estimated 2000 new cases of autoimmune blistering skin diseases per year. The incidence of pemphigus in Europe is one to two cases per million humans per year, and 80% have PV. BP is the most common type of subepidermal autoimmune blistering skin disease in Europe, with an incidence of about 13 cases per million humans per year. The next common types are mucous membrane pemphigoid and pemphigoid gestationis .
The standard of diagnostic testing for autoimmune blistering skin diseases is the direct immunofluorescence (IF) microscopy to demonstrate tissue-bound autoantibodies and/or C3 in the patients' skin or mucous membranes. The direct IF microscopy of the patient's serum can be used as a screening test for circulating antibodies. The diagnostic assessment of autoimmune blistering skin diseases can be expected to improve in the near future as new serological testing systems are developed that employ recombinant forms of the target antigens. But the treatments in use still need to be validated by prospective, controlled trials . An example for intradermal blistering pemphigus is PV.
Pemphigus vulgaris (PV) is a severe, chronic disease of the skin and mucous membranes with poor prognosis, dissecting, acantholytic blisters and erosion, characterized by the presence of antibodies against epidermal intercellular substance. PV is the classic example of autoantibody-induced immune dermatosis, which can be recurrent or relapsing. The specific IgG fraction of the pemphigus serum initiates acantholysis without complement. It is surmised that enzymatically induced destruction with plasminogen activator and pemphigus acantholysis factor occurs after binding of the pemphigus antibody to the surface of the epidermal cell .
Both genders are equally affected with the mean age of onset in the sixth and seventh decade of life, and the patients present with skin lesions, typically flaccid blisters . On the entire body surface as well as on the mucous membranes of the mouth, the blisters can be located. A large amount of skin can be affected at any given point leading to situations akin to severe burns. PV is characterized by the deposition of an autoantibody on the keratinocytes cell surface. This antibody is typically directed against a 130-kDa protein (desmoglein 3). Additional autoantibodies against desmoglein 1 have been detected. Histology reveals the presence of a suprabasilar intraepidermal split with acantholysis, and there are deposits of IgG and C3 on the corticokeratinocyte cell surface in the mid and lower or entire epidermis of perilesional skin or mucosa. The titers of IgG4 antikeratinocyte antibodies can be correlated with disease activity .
Pemphigus vulgaris was associated with a high morbidity and mortality. Introduction of corticosteroids reduced the mortality rate from 70 to 100% to a mean of 30% . However, long-term administration of high doses of corticosteroids can be associated with severe effects. Other therapeutic options include dapsone, gold, and systemic antibiotics. They are often used in combination with other immunosuppressant agents such as azathioprine, methotrexate, and cyclophosphamide. Recently newer therapeutic modalities such as TPE, ECP, mycophenolate mofetil, chlorambucil, dexamethasone-cyclophosphamide, IVIg therapy, and rituximab, anti-CD20 monoclonal antibody, have been investigated .
The rationale for introducing TPE in the treatment of PV is based on the presence of circulating pathogenic autoantibodies. TPE has been used in patients with severe symptoms who either received high doses of conventional agents and/or had an aggressive and rapidly progressive disease. TPE was used in patients in all age groups (13–80 years old). The duration of disease prior to using TPE ranged between 1 month and 25 years. The goal of TPE is to reduce the level of autoantibodies with subsequent improvement in clinical symptoms. The decline in autoantibody titers, anti-keratinocytes cell surface antibodies and anti-desmoglein 3, correlated with clinical response in many patients .
The antiepidermal antibodies, which usually belong to the IgG category, can be easily eliminated with TPE. The success rate of a combined therapy of immunosuppression with steroids and TPE is then over 95% . Standard therapy for PV is based on a combined administration of high-dosed glucocorticoids and immunosuppressive drugs. In patients with severe, life-threatening, or recalcitrant PV, stronger therapeutic options should be considered, such as “pulse-therapy” with discontinuous intravenous infusion of mega doses of immunosuppressive drugs over a short-time, TPE, and IA of pathogenic autoantibodies using the extracellular domain of the PV main antigen (desmoglein 3) produced by baculovirus or, more recently, a tryptophan-linked polyvinyl alcohol adsorber .
IA has been successfully applied in patients with severe atopic dermatitis and high total serum IgE levels . In recent years various immunoadsorption systems and immunosuppressive protocols have been used to reduce the circulating autoantibodies. With a single IA procedure, between 50 and 75% of the specific pemphigus anti-desmoglein IgG autoantibodies can be eliminated by different adsorbers . For obtaining durable effects of rapid decrease in circulating autoantibodies and immune complexes, IA must be combined with immunosuppressant treatment. The complication rates and side-effects are low and comparable with those of the other extracorporeal circulations.
In recent years ECP has also been applied to patients with serious cases of pemphigus with considerable success . The clinical response in patients who underwent ECP was observed after two to seven sessions (two daily procedures per cycle). The total number of cycles received varied from 2 to 48. The follow-up ranged between 4 and 48 months, and the disease was controlled in most patients .
Therapeutic plasma exchange protocols used in PV vary widely and have been usually based on the observed clinical response after each treatment. In the guidelines on the use of TA of the AAC of the ASFA, pemphigus vulgaris has category III for TPE, IA, and ECP with the recommendation grade 2 B and 2 C respectively (Table 3) .
Table 3. Therapeutic apheresis (TA) in dermatological diseases with immunologic origin
|Intraepidermal blistering pemphigus||1-1.5||human-albumin-electrolyte solution||daily or every other day|
|Pemphigus vulgaris||TPE, IA||+||TPE, IA, ECP||III||2B, 2C|
|Subepidermal blistering pemphigus|
|Bullous pemphigoid||TPE, IA||+||–||–||–|
|D-penicillinamine induced pemphigus||TPE, IA||+||–||–||–|
|Progressive scleroderma||TPE||+||TPE, ECP||III, III||2C|
Another form of subepidermal blistering pemphigus is the rare bullous pemphigoid (BP). BP frequently involves a premonitory stage with pruritic urticarial erythema and eczematous lesions followed by the classical bullous stage with tense blisters, erosions and crusts . BP is a chronic dermatosis often associated with acute exacerbations, with formation of bullae blisters usually on inflamed skin, subepidermal blister formation, and antibodies against the epidermal basal membrane. The pathophysiology is regarded as being a consequence of the combined effect of antigen, antibody, complement, and inflammatory cells, whereby lyosomal enzymes actually destroy the basal membrane zone and induce subepidermal blistering . It is still unclear whether bullous pemphigoid can be provoked by medication or ultraviolet light rays. It is also possible that destruction of the basal membrane zone with release of basal membrane antigens can cause a direct immunological response in predisposed people. Thus, BP can also occur in combination with other autoimmune disorders. IgG autoantibodies against it are present in about 85% of patients with BP [72, 73]. Most BP patients also develop IgA and IgE antibodies against BP 180 (immunodominant region of BP 180), and 60 to 70% of BP patients have circulating autoantibodies against BP230, but the presence of these antibodies is much less specific than that of anti-BP-180 antibodies for the diagnosis of BP and is not correlated with disease activity .
However, because the clinical disease is not as potentially life threatening as other autoimmune diseases, the course of this pemphigus disorder is not as dramatic as other forms of the disease, with good response to high-potency corticosteroids, which are usually combined with dapsone, doxycycline, methotrexate or azathioprine . BP has an annual incidence of about 13 to 42 new cases per 1 million in central Europe and UK. Only a few cases have been treated with TPE up to now.
Immunoadsorption has been successfully applied in patients with severe BP and can be performed either with different single use or reusable adsorbers. The latter are much more effective than the former, enabling a 75% reduction of autoantibodies in a single IA and 95% reduction when IA is performed on three consecutive days [66, 75]. Various protocols for the use of IA in BP have been tested in combination with immunosuppression [66, 69]. In all studies, the introduction phase consisted of three or four IA treatments on consecutive days, usually with high-affinity adsorbers. All patients benefitted from the treatment. The main advantages of IA is its rapid clinical effect, often resulting in the healing of all lesions within a few days.
Because the pathogenic relevance of autoantibodies was clearly demonstrated in the majority of autoimmune bullous diseases, removal of autoantibodies, therefore, appears to be a rational therapeutic approach for these patients. Immunoadsorption has been shown to effectively lower the antibody levels and leads to rapid clinical responses in patients with immuno bullous disorders . Meanwhile, IA and rituximab have been established as further therapeutic options [75, 76].
D-penicillamine-induced steroid-resistant pemphigus should also be mentioned. This foliaceus-type disease with its high mortality rate, which can occur as a side-effect in long-term penicillamine therapy, is a particular indication for TPE . The functioning mechanism by which this drug induces acantholysis of the epidermis has still not been clarified. It is generally believed that similar immunological processes are involved to those in pemphigus vulgaris. The final step in anti-Dsg induced acantholysis is the response of the keratinocytes to autoantibodies binding via downstream signaling events and eventual keratin filament retraction and apoptosis, as many signaling pathways have been implicated in anti-Dsg induced acantholysis .
In drug-induced pemphigus, it was demonstrated that autoantibodies have the same antigenic specificity, on a molecular level, as autoantibodies from other pemphigus patients . The chance of acquiring pemphigus after penicillinamine intake of least 6 months is 7%. More medications have been reported since then to evoke pemphigus, such as penicillin, ampicillin, rifampicin, pyrazolon derivates, a combination of aspirin and indomethacin, and a combination of propanol and mepbromate . Drugs “at risk” for pemphigus are sulfhydryl (SH)-group containing drugs, known as thiol-drugs (i.e., captopril). Drug-induced and drug-triggered pemphigus are considered to be separate entities. In drug-triggered pemphigus, the drug only stimulates a predisposition to develop active autoimmune disease. It seems that penicillamine and SH-containing drugs actually induce pemphigus, whereas other drugs only trigger a disimmune mechanism previously programmed and ready to be set off. Drug-triggered pemphigus is known to be refractory to therapy if the offending drug is not stopped immediately .
Immunosuppressive therapy is directed at preventing or slowing the rebound of antibody and immune complex formation after TA so as to sustain the therapeutic effect, given that suppression of a rebound through renewed antibody synthesis is very important for the further course of the disease. In recent years only case reports of D-penicillamine-induced pemphigus treated successfully with TA were reported. It is generally recommended to combine TA with immunosuppression. This time-consuming treatment has to be repeated in short time intervals (Table 3).
IA is the more specific therapeutic option, in which only the pathogenic IgG is depleted in the patient's plasma. IgG autoantibodies are adsorbed on anti-human IgG affinity agarose column. Resynthesis of IgG autoantibodies was inhibited by postapheresis IVIg, therefore the additional effect of IA is difficult to observe since IVIg has also an immunomodulatory potency . A combination of IA and rituximab showed rapid and long-lasting response of concomitant immunosuppressive medication . Rituximab is almost given as an adjuvant drug, i.e., in addition to another type of immunosuppressive treatment. Complications of rituximab in patients with autoimmune blistering skin diseases include infections, deep venous thrombosis of the lower limbs, pulmonary embolism, long-term hypogammaglobulinemia, and neutropenia with an overall mortality of 4%. The indications, contraindications and dosage of rituximab treatment for autoimmune blistering skin diseases has been established as well as the variables that should be monitored over the course of treatment, and the criteria for discontinuing rituximab .
Other Forms of Dermatosis
Scleroderma or systemic sclerosis is a rare generalized autoimmune disease. Scleroderma is characterized by vascular abnormalities, fibrosis, inflammatory changes, and late stage atrophy/obliterative vasculopathy. Localized scleroderma forms show a longitudinal or circumscribed skin involvement . The effectiveness of TPE in progressive scleroderma and dermatomyositis is still disputed (Table 3).
Pyoderma gangrenosum (PG) is a rare, polyetiological syndrome based on a pathological immune reaction . In over 40% of cases, this disease occurs together with ulcerative colitis. In the vessel walls of vasculitic lesions, granular IgG, C3, complement, and IgM deposits have been observed. PG is a noninfectious neutrophilic dermatosis that usually starts with sterile pustules, which rapidly progress to painful ulcers of variable depth and size with undermined violaceous borders. In 17 to 74% of cases, PG is associated with an underlying disease, most commonly inflammatory bowel disease, rheumatological or hematological disease or malignancy. Diagnosis of PG is based on a history of underlying disease, typical clinical presentation and histopathology, and exclusion of other diseases that would lead to a similar appearance. PG is characterized by painful, enlarging necrotic ulcers with bluish undermined borders surrounded by an advancing zone of erythema; its clinical variants include: ulcerative or classic, pustular, bullous or typical, vegetative, peristomal, and drug-induced. Subcorneal pustular dermatosis is an uncommon relapsing symmetric pustular eruption that involves flexural and intertriginous areas; it can be idiopathic or associated with cancer, infections, medications, and systemic diseases [84, 85]. Because the incidence of PG is low, no prospective randomized controlled trials and only a few studies with case numbers of more than 15 patients have been published. To date no guidelines for treatment of PG have been established .
Therapeutic efficacy of systemic treatment with corticosteroids and cyclosporine A is documented in the literature for disseminated as well as for localized disease and should be considered first-line therapy. In cases refractory to this treatment, alternative therapeutic procedures (e.g., systemic corticosteroids, and mycophenolate mofetil; mycophenolate mofetil and cyclosporine; tacrolimus; infliximab, or TPE) are recommended . Despite recent advances in therapy, the prognosis of PG remains unpredictable.
Henoch-Schönlein purpura (HSP) is a systemic vasculitis that affects vessels of a small caliber. The vascular purpura is usually confined to the lower limbs and is associated, at varying degrees, with joint, gastrointestinal and renal involvement. It is a systemic disease where antigen-antibody (IgA) complexes activate the alternate complement pathway, resulting in inflammation and small vessel vasculitis .
In 1990, the American College of Rheumatology defined HSP by the presence of two or more of the following criteria: age of disease onset (20 years or younger); palpable purpura; acute abdominal pain and granulocytic infiltration in the walls of arterioles or venules . Focusing on the pathogenic role of IgA immune complexes in HSP, the Chapel Hill Consensus Group view the diagnosis as a small vessel vasculitis with predominant IgA vascular deposits. All patients develop palpable purpura. In the skin, these deposits lead to subepidermal hemorrhage and small vessel necrotizing vasculitis producing the purpura . IgG autoantibodies directed at mesangial antigens may also play a role in pathogenesis. In other organs, necrotizing vasculitis leads to organ dysfunction or hemorrhage. Nonetheless, the precise role of IgA or antibodies to it in the pathogenesis of the disease remains unclear .
In the ASFA guidelines on the use of TPE, the crescentic form and severe extrarenal manifestations of the HSP has category III with the recommendation grade 2 C for TPE (Table 3) . Prospective randomized clinical studies proving treatment efficacy are still lacking. Spontaneous recovery even in patients with severe clinical and histologic presentation and of late evolution to chronic kidney disease in patients with mild initial symptoms renders it difficult for treatment protocols. Prospective international multicenter studies looking at determinants of clinical and histopathological evolution as well as possible circulating and urinary markers of progression are necessary .
Other dermatological diseases such as necrotic xanthogranuloma, scleromyxedema, or epidermal necrolysis are not mentioned due to the oncological treatment or due to a lack of clinical data.
As noted by Malchesky , every effort should be made to delay the progression of chronic diseases. Therapeutic apheresis is clearly and important tool in the treatment of many complex conditions now and in the near future.
All mentioned therapeutic apheresis methods are still technically complicated and very expensive. A reduction in costs is a valid demand in view of the scarce resources available in the healthcare system. Commissions consisting of physicians, administration specialists and representatives of the health insurance funds and others nowadays decide at a “round table” who will be granted medical facilities and who will not; this is a clinical routine adopted only in Germany. Physicians are committed to helping all of the patients entrusted to them to the best of their knowledge, and this means that medical treatment–and particularly the apheresis processes–must become affordable. This represents a great demand to physicians, politicians, health organizations, and above all, to the manufacturers. Industry constantly justifies the high costs with the extensive research and development required. All those involved in healthcare must intensify their cooperation in this respect.
Nevertheless, medical processes are advancing and will not be stopped. Since the introduction of hollow fiber membranes, exceptional efforts in research and development have been undertaken in the apheresis sector alone, enabling, for example, the introduction of selective separation techniques into everyday clinical practice–techniques that were unthought of at the beginning of the 1980s. This is reflected in the numerous national and international specialist congresses, which take place each year.