Brief Report: AA Amyloidosis Complicating the Hereditary Periodic Fever Syndromes

Authors


Abstract

Objective

AA amyloidosis is a life-threatening complication of the hereditary periodic fever syndromes (HPFS), which are otherwise often compatible with normal life expectancy. This study was undertaken to determine the characteristics, presentation, natural history, and response to treatment in 46 patients who had been referred for evaluation at the UK National Amyloidosis Centre.

Methods

Disease activity was monitored by serial measurement of serum amyloid A. Renal function was assessed by measurement of serum creatinine and albumin levels, the estimated glomerular filtration rate, and proteinuria from 24-hour urine collections. The amyloid load was measured by serum amyloid P scintigraphy.

Results

Twenty-four patients had familial Mediterranean fever, 12 patients had tumor necrosis factor receptor–associated periodic syndrome, 6 patients had cryopyrin-associated periodic syndromes, and 4 patients had mevalonate kinase deficiency. The median age at onset of HPFS was 5 years; median age at presentation with AA amyloidosis was 38 years. Diagnosis of an HPFS had not been considered prior to presentation with AA amyloidosis in 23 patients (50%). Eleven patients (24%) had end-stage renal failure (ESRF) at presentation; of these, 3 had received transplants prior to referral. A further 13 patients developed ESRF over the followup period, with 10 undergoing renal transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (interquartile range [IQR] 2–8), with a median time to transplant of 4 years (IQR 3–6). Eleven patients (24%) died. The median survival in the entire cohort was 19 years from diagnosis of AA amyloidosis. Of the 37 patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression, 14 (38%) showed a stable amyloid load, and 2 (5%) showed increased amyloid deposition over the followup period.

Conclusion

AA amyloidosis remains a challenging and serious late complication of HPFS; however, outcomes are excellent when HPFS is diagnosed early enough to allow effective treatment, thus preventing or retarding further amyloid deposition and organ damage.

Hereditary periodic fever syndromes (HPFS) are rare genetic autoinflammatory disorders characterized by recurrent episodes of fever and acute multisystem inflammation in the absence of an infectious or autoimmune stimulus. The most widely described of these are familial Mediterranean fever (FMF), tumor necrosis factor receptor–associated periodic syndrome (TRAPS), cryopyrin-associated periodic syndromes (CAPS), and mevalonate kinase deficiency (MKD). The syndromes are characterized by a marked acute-phase response, with some patients experiencing a 100-fold or more increase in the circulating concentration of the acute-phase protein serum amyloid A (SAA). When adequately suppressed, these diseases are associated with normal life expectancy, but a proportion of patients develop the life-threatening complication AA amyloidosis, with SAA acting as the amyloidogenic precursor protein. The period of latency between the onset of inflammation and clinical presentation with AA amyloidosis is variable and may be prolonged, but amyloidosis progression can be rapid. Renal dysfunction is the predominant presenting feature, and poor outcomes are associated with inadequate suppression of the underlying inflammation (1). We sought to study the presentation, phenotype, and outcome of disease in patients with HPFS-associated AA amyloidosis in a single national referral center.

PATIENTS AND METHODS

Patients and diagnosis.

From our database of 854 patients with a sequence variant in a gene associated with HPFS and 545 patients with (confirmed or probable) AA amyloidosis, we identified a cohort of 46 patients with AA amyloidosis associated with an HPFS. This comprised all patients referred to our center in the 21 years leading up to September 2011 in whom an HPFS was diagnosed based on a combination of clinical presentation, medical history, genetic sequencing, and additional investigation, and in whom AA amyloidosis had been confirmed by immunohistochemical analysis or by whole body 123I–serum amyloid P (SAP) scintigraphy and additional investigation. Routine investigation and assessment at each visit included clinical evaluation, electrocardiography and echocardiography, and measurements of hepatic and renal function, including 24-hour urinary protein excretion. Patients underwent comprehensive clinical assessment at baseline and were followed up every 3–6 months. Ethical approval was obtained for this retrospective study (Riverside Research Ethics Committee reference no. 06/Q0501/42).

Genetic analysis.

Genomic DNA was isolated from patients' peripheral blood as described by Talmud et al (2). Sequence variants were identified by polymerase chain reaction (PCR) and direct sequencing of the appropriate exons of the gene in question. Genes and exons analyzed were as follows: MEFV exons 2 and 10; TNFRSF1A exons 2 and 3 including intron 2, exons 4 and 5 including intron 4, and exons 6 and 7 including intron 6; NLRP3 exon 3; and MVK exons 9 and 11. Analysis was extended to other exons where necessary. PCR results were validated by gel electrophoresis.

Histologic and immunohistochemical assessment.

The presence of amyloid in tissue sections was confirmed by a modified version of the alkaline-alcoholic Congo red method described by Puchtler et al (3). Formalin-fixed deparaffinized tissue sections, 6–8 μm thick, were stained and viewed in brightfield and under cross-polarized light. Positive controls were obtained from a known Congo red–positive composite block and were always processed in parallel. Immunohistochemical staining of formalin-fixed deparaffinized 2-μm sections of amyloidotic tissue was performed using commercial monoclonal antibodies against SAA protein (Euro-Diagnostica) and κ and λ amyloid L (Dako) to determine the amyloid fibril type (4). Positive and negative controls were used in each run.

SAP scintigraphy.

We performed SAP scintigraphy, a nuclear medicine technique that involves the intravenous injection of a highly purified SAP, which has been radiolabeled with the gamma-emitting isotope 123I; radiolabeled SAP localizes rapidly and specifically to visceral amyloid deposits in proportion to the amount of amyloid present (5). This technique has 100% diagnostic sensitivity in patients with systemic AA amyloidosis (6).

C-reactive protein (CRP), SAA, and renal function testing.

CRP was measured in the serum using a high sensitivity automated latex microparticle–enhanced immunoturbidimetric assay (Cobas Mira; Roche). The lower limit of detection was 0.2 mg/liter, with an interassay coefficient of variation (CV) of 4.2% at 4 mg/liter and 6.3% at 1 mg/liter. SAA was measured in serum by latex nephelometry (BNII autoanalyser; Dade Behring). The lower limit of detection was 0.7 mg/liter, with an interassay CV of 2.6% at 15 mg/liter and 3.7% at 80 mg/liter. Standardization of both CRP and SAA assays was based on the respective 1987 World Health Organization international reference standards. Renal function was measured by monitoring creatinine levels, albumin levels, and estimated glomerular filtration rate from serum, and proteinuria from 24-hour urine collections.

Renal replacement therapy and renal transplantation.

Renal replacement therapy and renal transplantation were performed at the patients' local centers according to local protocols.

RESULTS

Characteristics of the entire cohort.

Gene mutations, ethnic origins, and age at onset of disease for all patients in the cohort are shown in Table 1. The median age at diagnosis of AA amyloidosis was 38 years (interquartile range [IQR] 27–47). Thirty-seven patients had a clinical history compatible with an HPFS. The median age at symptom onset was 5 years (IQR 2–13), and the median latency between symptom onset and presentation with AA amyloidosis was 23 years (IQR 17–34). Eight patients reported having no history of overt inflammatory symptoms, and complete clinical data were unavailable for 1 patient. In 23 patients (50%), HPFS was diagnosed at our center following presentation with AA amyloidosis. Renal presentation of amyloidosis predominated; however, 3 patients also had liver amyloidosis diagnosed by scintigraphy, and 1 patient had cardiac amyloidosis, which was diagnosed postmortem.

Table 1. Mutations, ethnic origins, sex, and clinical characteristics of the 46 patients with AA amyloidosis complicating HPFS*
PatientEthnicitySexSequence variants/mutationsAttack symptomsAge at HPFS onset, yearsAge amyloidosis diagnosed, yearsLatency period, years
  • *

    HPFS = hereditary periodic fever syndromes; F = fever; A = abdominal pain; P = pleuritic chest pain; NA = not applicable; J = joint pain/arthralgia/swelling; R = rash; Ft = fatigue/malaise; H = headache; N = nausea; V = vomiting; G = gastrointestinal disturbance; M = myalgia; L = lymphadenopathy; E = red/swollen eyes; S = sweats; Ri = rigors; O = oral ulcers; St = sore throat.

  • Mutations in MEFV in familial Mediterranean fever (FMF), in TNFRSF1A in tumor necrosis factor receptor–associated periodic syndrome (TRAPS), in NLRP3 in cryopyrin-associated periodic syndromes (CAPS), and in MVK in mevalonate kinase deficiency (MKD).

FMF       
 1Northern EuropeanFM694del/E148QF, A, P105949
 2Northern EuropeanFK695R homoAsymptomaticAsymptomatic61NA
 3Northern EuropeanMM694delF, A, P104535
 4Northern EuropeanMM694V hetAsymptomaticAsymptomatic78NA
 5Northern EuropeanMM694V/E148QAsymptomaticAsymptomatic63NA
 6TurkishFM694V homoF, A, J32724
 7TurkishMM694V hetAsymptomaticAsymptomatic45NA
 8TurkishFM694V homoF, A, J15249
 9TurkishMM694V/E148QF, A, J, R, Ft72720
 10TurkishMM694V homoF, A, P172619
 11ArabicFV726A/M694IF, A73629
 12ArabicMM694V homoA, J13196
 13ArabicFV726A/ M694VF, A, J306232
 14ArabicMM694I/ E148QF, A415817
 15ArabicFM694V/M680IF, H103525
 16GreekMM694V hetF, A, P243814
 17GreekMV726A/F479LF, A, J31916
 18GreekMV726A/E167D/F479LAsymptomaticAsymptomatic67NA
 19EgyptianMM694V/V726AA, J214221
 20EgyptianMM680I homoF, A, P, N, V254116
 21ArmenianFM680I/V726AF, A, P435815
 22ArmenianFV726A/ M694VF, A, P, H, N374
 23Jewish-SephardiFM694V homoF, A, P, J, G63226
 24South AsianFS154P hetAsymptomaticAsymptomatic37NA
TRAPS       
 25Northern EuropeanFD42delF, A, P, R, J52015
 26Northern EuropeanFH22QF, A, P, R, J, M, L, EUnknown30Unknown
 27Northern EuropeanMT50MF, A, R, J, E<13130
 28Northern EuropeanMT37IA, M, F, R, Ft22826
 29Northern EuropeanFC33YA, M, E, R22422
 30Northern EuropeanMD42delF, A, M, J, R64438
 31Northern EuropeanFR92PF, A, S184628
 32Northern EuropeanFC33YF, A, M, R, S, Ft, Ri34239
 33Northern EuropeanMT50MA, S, M, Ri33936
 34Northern EuropeanFD42delF, A, P, R, J, G, Ri44642
 35Northern EuropeanMC33YF, A, P, R, J, E14645
 36Northern EuropeanFY38SF, R, J, M, E47571
CAPS       
 37Northern EuropeanMA439VAsymptomaticAsymptomatic52NA
 38Northern EuropeanMT348MR, F, M, J12928
 39Northern EuropeanMT348MR, E, F,<11514
 40Northern EuropeanMR260WR, M<12322
 41South AsianMR260WR, E, F, J102919
 42South AsianFR260WR, E, F, J74538
MKD       
 43Northern EuropeanML234P/V337IF, L, V, G, A, H<12322
 44Northern EuropeanMI268T/V377IF, L, V, G, N, O, J, Ft11514
 45Northern EuropeanFI268T/V377IF, L, G, R, J, St<12625
 46South AsianMS52N/D386NAsymptomaticAsymptomatic47NA

Patients with FMF.

Of the 24 patients with FMF, 79% were born outside of Europe; the majority of patients were born in the eastern Mediterranean region. The median age at diagnosis of AA amyloidosis was 41 years (IQR 28–58). Six patients had a family history of FMF, and only 1 had a family history of AA amyloidosis. Two patients were untreated: 1 was asymptomatic with normal levels of inflammatory markers, and 1 died of metastatic cholangiocarcinoma almost immediately after the diagnosis of AA amyloidosis and genetic testing. Colchicine treatment was initiated in the remaining 22 patients, with complete remission achieved in 19 and partial remission in 1. Two patients did not tolerate the treatment: 1 continued to take low daily doses (<1 mg) despite severe gastrointestinal side effects until she died of progressive cardiac amyloidosis 5 years later; the other remains untreated, receiving long-term dialysis. Followup data were available for 18 patients, for a median followup period of 11 years. Two patients were receiving dialysis at presentation through last followup. Of the rest, 7 patients experienced improvement of proteinuria; however, only 3 had stabilization of chronic kidney disease (CKD). Eight patients showed amyloid regression on SAP scan, and the remainder showed a stable load over time. Two patients underwent renal transplantation.

Patients with TRAPS.

Ten of the 12 patients with TRAPS had a family history of the disease, and 9 (from 4 known kindreds) had a family history of AA amyloidosis. The median age at diagnosis of AA amyloidosis was 41 years (IQR 29–47). Six patients were treated with the anti–tumor necrosis factor agent etanercept: 1 patient did not tolerate the treatment, 1 achieved partial remission, and 4 had only a transient response and were subsequently switched to anakinra treatment, which was successful. A further 4 were successfully treated with anakinra initially. Four patients have died. Two of those patients had never received definitive treatment for TRAPS: 1 died of progressive AA amyloidosis at age 49 years, and the other died of sepsis following a second renal transplant at age 60 years. Of the 2 remaining patients, 1 patient who was receiving dialysis died of disseminated tuberculosis after receiving long-term anticytokine treatment for immunosuppression, and the other patient died of cervical cancer at age 43 years, several years after receiving renal transplant.

Followup data are available for the 8 patients who received an anti–interleukin-1 (anti–IL-1) agent. The median treatment duration was 23 months; 2 patients developed end-stage renal failure (ESRF) and underwent renal transplantation before switching to anti–IL-1 treatment. Of the others, 3 patients experienced improvement in proteinuria and stable or improved CKD, and 3 had worsening CKD over a median followup period of 65 months, although dialysis was required in only 1.

Patients with CAPS.

Of the 6 patients with CAPS, 4 were of northern European ancestry from separate kindreds and 2 were cousins of south Asian ancestry. Three of the 6 patients had a family history of CAPS, and only the south Asian cousins had a family history of AA amyloidosis. The median age at diagnosis of AA amyloidosis was 31 years (IQR 25–42). Four patients were treated with anti–IL-1 agents, with dramatic clinical and laboratory improvement. The 2 other patients died before the role of IL-1 in CAPS was recognized; 1 patient was treated with colchicine and steroids without benefit and the other was untreated, CAPS having been diagnosed posthumously. Of the 4 patients treated with anti–IL-1 agents, 1 had received a renal transplant prior to initiation of this treatment. All of the remaining 3 patients have had resolution of proteinuria over the followup period. Three of the 4 patients have had stable CKD, and disease in 1 patient progressed from CKD stage 1 to stage 2 over the 11-year followup period, although his SAP scan showed amyloid regression.

Patients with MKD.

Of the 4 patients with MKD, only 1 had a family history of MKD, with a sibling subsequently diagnosed, and none had a family history of AA amyloidosis. The median age at diagnosis of AA amyloidosis was 25 years (IQR 22–32). Of note, all 4 patients were diagnosed as having MKD after presentation at our center with AA amyloidosis, and none of those patients had received previous treatment. Three patients had suggestive symptoms with onset in early childhood, but the diagnosis of HPFS had never been considered; the fourth patient reported nonspecific malaise only. Three patients presented with incipient ESRF, and the fourth had severe nephrotic syndrome and developed dialysis-dependent renal failure within months of being diagnosed as having AA amyloidosis. Prior to diagnosis, 1 patient underwent cadaveric renal transplantation, and 2 patients received renal grafts from their mothers. Three patients were treated with various anticytokine agents over the followup period, and 1 received renal transplant–associated immunosuppressive agents only, with modest benefit.

Of the patients who received anticytokine treatment, 1 appears to have sustained 7-year partial remission with etanercept. Partial remission was achieved in 1 patient with IL-1 blockade, but the patient developed an anaphylactic reaction; he failed to respond to etanercept but a therapeutic trial of tocilizumab has been successful. The third patient failed to respond to anakinra, but a 14-month complete remission was sustained with tocilizumab, and regression of amyloid was seen on SAP scan (Figure 1). One patient died at age 45 years, with transplant rejection due to chronic allograft nephropathy after 7 years. In another patient, graft rejection occurred after 6 years due to recurrent AA amyloidosis.

Figure 1.

Serial 123I–serum amyloid P scans obtained before (left) and after (right) treatment of mevalonate kinase deficiency with the anti–interleukin-6 agent tocilizumab, demonstrating amyloid regression following treatment.

Renal function in the overall cohort.

Twenty patients (49%) developed ESRF. Eleven (24%) had ESRF at presentation, and disease progressed to ESRF in a further 9 patients (20%) over the followup period. Thirteen patients in the cohort underwent renal transplantation; 3 of these were prior to referral to our center. Disease progressed to ESRF in a further 13 patients over the followup period, with 10 undergoing transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (IQR 2–8), with a median time to transplant of 4 years (IQR 3–6). Table 2 summarizes the characteristics of patients who received kidney transplants. Of the entire cohort, 11 patients (24%) experienced improvement in proteinuria, as defined by consensus criteria (7), with a median decrease in urine protein of 4.8 gm/24 hours (IQR 2.9–5.7) over the followup period. Five of these patients showed regression of amyloid on SAP scintigraphy, and 6 showed a stable amyloid load. Nine experienced complete remission in response to treatment of the HPFS, and 2 were untreated.

Table 2. Characteristics of and outcome in the 13 patients who underwent renal transplantation*
PatientHPFSTreatmentTreatment responseESRF at presentationTime to ESRF from onset of HPFS, yearsTime to ESRF from diagnosis of amyloidosis, yearsTime to transplant from amyloidosis diagnosis, yearsGraft survival, yearsReason for graft failureCause of patient death
  • *

    CMV = cytomegalovirus; TNF = tumor necrosis factor; IL-1 = interleukin-1 (see Table 1 for other definitions).

  • Patient developed end-stage renal failure (ESRF) and received a transplant prior to diagnosis of AA amyloidosis.

7FMFColchicineCompleteNo262.626.788.13NANA
12FMFColchicineCompleteNo4111.8715.030.04Patient deathCMV sepsis posttransplant
17FMFColchicinePartialNo1746.004.96NANA
24FMFColchicineCompleteYes22−3.59−2.313.61NANA
25TRAPSUntreatedNARenal transplant prior to presentation1524.0020.9Patient deathCervical cancer
28TRAPSUntreatedNAYesUnknown02.0017Patient deathRenal failure secondary to recurrent amyloid in graft
30TRAPSAnti-TNFCompleteRenal transplant prior to presentation2604.0016.25NANA
31TRAPSAnti–IL-1CompleteNo295.685.926.38NANA
37TRAPSAnti-TNFIntolerantNo471.662.838.13Patient deathSepsis post-second renal transplant
41CAPSAnti–IL-1CompleteRenal transplant prior to presentation18.2503.384.73NANA
45MKDAnti-TNFCompleteYes24.711.873.875.54NANA
46MKDAnti–IL-1PartialNo16.1202.056.08Recurrent amyloid in graftNA
47MKDUntreatedNAYes2827.007Patient deathUnknown

Survival of the overall cohort.

Eleven patients (24%) died (1 patient with CAPS, 4 patients with TRAPS, 1 patient with MKD, and 5 patients FMF). Survival of the cohort was calculated using Kaplan-Meier analysis. Median survival of the entire cohort was 19 years from diagnosis of AA amyloidosis; the median age at death was 67 years, with no deaths occurring before age 43 years.

Thirty-seven patients (80%) experienced a complete or partial response to treatment of the underlying HPFS: 20 FMF patients, 9 TRAPS patients, 5 CAPS patients, and 3 MKD patients. Of these patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression and 14 (38%) showed a stable amyloid load over the followup period. Four (11%) did not have a repeat SAP scan, and 2 (5%) showed increased amyloid deposition over the followup period.

DISCUSSION

The risk of developing AA amyloidosis in the hereditary periodic fever syndromes is difficult to characterize based on this cohort, for several reasons. First, much of the data are historical, dating back to when many of the effective treatments in current use were unavailable. Second, increasing age is a known risk factor for AA amyloidosis; presentation in childhood is exceedingly rare, and as such, including pediatric patients will result in a prevalence underestimation. Furthermore, as the HPFS are generally newly described entities, many adults were not diagnosed in earlier decades and are now lost to followup, so current cohorts are heavily biased toward children. In this case series of adults (age >18 years), the 24 patients with FMF represented 6%, the 12 patients with TRAPS represented 18%, the 6 patients with CAPS represented 10%, and the 4 patients with MKD represented 18%, of all adult FMF, TRAPS, CAPS, and MKD patients, respectively, under our care.

Early diagnosis and initiation of treatment of the HPFS is important in preventing the development of AA amyloidosis. Early diagnosis can be problematic, as these diseases are rare, and a high index of suspicion is required. Furthermore, clinical features of the HPFS overlap with those of other more common diseases. Broad and inconstant phenotypes combined with variable penetrance add further diagnostic challenges. Finally, recognition of asymptomatic patients with subclinical inflammation (17% of this cohort) before they develop devastating complications is difficult as it relies on serendipitous detection of abnormal inflammatory marker levels and recognition of the importance of this finding.

Further difficulties include the expense and time associated with sequencing multiple genes and exons. Where the capacity to perform such testing is unavailable, attempts to narrow the differential diagnosis clinically can be worthwhile. We routinely monitor disease activity using a combination of patient diaries and serial measurement of serum inflammatory markers. In those with suggestive symptoms accompanied by elevated CRP and SAA levels, a trial of therapy can be very revealing. Responses to colchicine, corticosteroids, or biologic agents can help to establish a definitive diagnosis. In addition, a successful therapeutic trial can allow effective management of both symptoms and complications in cases where the disease etiology remains unknown even after extensive genetic investigation.

This series demonstrates that even in patients with established AA amyloidosis, effective treatment of the underlying HPFS can lead to improved renal function and regression of amyloid, as long as renal impairment is not too advanced at time of diagnosis. Outcome of renal transplantation in these patients is good, and for those who reach ESRF, this should certainly be considered as an option. However, the aim of treatment has to be the complete prevention of this devastating complication, which has negative effects on quality and length of life.

AUTHOR CONTRIBUTIONS

All authors were involved in drafting the article or revising it critically for important intellectual content, and all authors approved the final version to be published. Dr. Lachmann had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study conception and design. Lane, Hawkins, Lachmann.

Acquisition of data. Lane, Loeffler, Rowczenio, Gilbertson, Bybee, Russell, Gillmore, Wechalekar, Hawkins, Lachmann.

Analysis and interpretation of data. Lane, Lachmann.

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