Second transplant with two unrelated cord blood units for early graft failure after haematopoietic stem cell transplantation


Vanderson Rocha, MD, PhD, Hôpital Saint Louis, 1 Av Claude Vellefaux, 75010, Paris, France.


Graft failure (GF) can be a fatal complication following haematopoietic stem cell transplantation (HSCT). We report four patients who developed early GF after unrelated HSCT and who subsequently received a double unrelated cord blood transplant (dUCBT) after reduced-intensity conditioning, at a median 15 d after the decision to perform a second transplant. Neutrophil recovery was observed in all four patients between day +15 and +31 with full donor chimaerism of one unit. Acute GVHD grades II–IV was observed in three patients. Three are alive, between 12 and 25 months after dUCBT. In conclusion, dUCBT is a promising procedure to treat early GF.


Graft failure (GF) is a severe complication following haematopoietic stem cell transplantation (HSCT). Risk factors for GF include human leucocyte antigen (HLA)-disparity, T-cell depletion and low-cell dose (Gluckman et al, 1997; Davies et al, 2000). Haematopoietic growth factors (granulocyte colony-stimulating factor, G-CSF), infusion of cryopreserved autologous stem cells or second allogeneic HSCT preceded by further immunosuppressive conditioning are the main therapeutic options (Grandage et al, 1998;Guardiola et al, 2000). Concerning second transplants, the original donor may be difficult to access or unavailable, mainly in the unrelated HSCT setting. Therefore, unrelated cord blood (UCB) units may be a useful source of stem cells to rescue these patients, considering their greater availability and higher degree of tolerated HLA-mismatches (Barker et al, 2002). To date, the use of multiple umbilical CB units in the setting of GF has not been described. We report four cases of second transplants using two CB units after GF.

Complete details on donor cell and recipient characteristics are given in Table I.

Table I.   Detailed characteristics of patients receiving a double cord blood transplantation for early graft failure after a previous HSCT.
 Patient 1Patient 2Patient 3Patient 4
  1. SAA, severe aplastic anemia; CML, chronic myeloid leukemia; AML, acute myeloid leukaemia UCB, unrelated donor cord blood; BM, bone marrow; Bu, i.v. busulfan; Cy, cyclophosphamide; Flud, fludarabine; FTBI, fractionated total body irradiation; Mel, melphalan; ATG, anti-thymocyte globulin; CsA, ciclosporin A; NA, not available; MMF, mycophenolate mofetil; MP, methylprednisolone CMV, cytomegalovirus; VZV, varicella zoster virus; aGVHD, acute graft-versus-host disease; cGVHD, chronic graft-versus-host disease; RSV, respiratory syncytial virus; PTLD, post-transplant lymphoproliferative disease; a HLA (human leucocyte antigen) typing for cord blood units – serologic for class I; high resolution for class II, b HLA typing for bone marrow donor High resolution for class I and class II; c aGVHD was graded according to Glucksberg criteria (Glucksberg et al, 1974).

Characteristics of first transplants
Monosomy 7
Donor typeUnrelated BMSingle UCBSingle UCBSingle UCB
Number of HLA mismatching (loci)
 Class I1 (C)1 (B)2 (A,B)1 (B)
 Class II01 (DRB1)1 (DRB1)1 (DRB1)
Total nucleated cells at infusion/kg × 10711·53·32·31·9
CD34+ cell dose at infusion/kg × 10594·62·31·50·84
Conditioning regimenCy 120 mg/kgBu 4,8 mg/kgBu 12,8 mg/kgFlud 90 mg/m2
FTBI 12 GyCy 40 mg/kgMel 140 mg/m2Mel 140 mg/m2
 Flud 90 mg/m2ATG 10 mg/kg 
 ATG 10 mg/kg  
GVHD prophylaxisCsACsACsACsA
GVHDaGVHD (grade I)NoNoNo
InfectionsNoCMV, HHV-6ToxoplasmosisCMV
Chimaerism76% donor (D + 27)100% donor (D + 39)NA100% recipient (D + 12)
 100% recipient (D + 40)37% donor (D + 67)NA100% recipient (D + 61)
Time between the decision and the second transplant (days)16142814
Interval between transplants (days)56817576
Characteristics of second transplants
Donor type2 UCB2 UCB2 UCB2 UCB
Number of HLA mismatching (loci) (first unit)
 Class I1 (B)2 (A,B)2 (A,B)2 (A, B)
 Class II  1 (DRB1)1 (DRB1)
Number of HLA mismatching (loci) (second unit)
 Class I1 (B)2 (A,B)2 (A,B)1 (B)
 Class II  1 (DRB1)1 (DRB1)
Total nucleated cells at infusion/kg × 1073,12,95,96,5
CD34+ cell dose at infusion/kg × 1052,21,53,25,7
Conditioning regimenCy 35 mg/kgCy 50 mg/kgCy 35 mg/kgCy 50 mg/kg
Flud 90 mg/m2Flud 90 mg/m2Flud 120 mg/m2Flud 90 mg/m2
ATG 10 mg/kgTBI 2 GyATG 5 mg/kgTBI 2 Gy
GVHD prophylaxisCsACsACsACsA + MMF
Neutrophil (>0·5 × 109/l) and platelets (>20 × 109/l) recovery (days after second transplant)31/12727/11219/4215/NA
Chimaerism (first unit = D1, second unit = D2)
 Day 3080%D1, 20%D2NANA100% D1
 Day 60100% D2NANA
 Day100100% D2100% D2100% D1-
Acute GVHDNoaGVHD grade IIaGVHD grade IIaGVHD grade IV
Chronic GVHDExtensiveLimitedExtensive
Infectious complicationsPTLD (EBV), HSVRSV, CMV, VZVCMVAdenovirus
Survival postsecond transplant25 months12 months12 months46 days

Patient 1

A 38-year-old man, with chronic myeloid leukaemia (CML) after failure of imatinib treatment, was transplanted with an HLA-mismatched (9/10) unrelated bone marrow (BM) after myeloablative conditioning. At D + 27, a BM aspirate showed absence of engraftment with a mixed chimaerism (76% donor). Despite G-CSF, chimaerism at D + 40 confirmed GF, and a second HSCT was programmed. He received 2 UCB units, 56 d after the first transplant. Conditioning consisted of cyclophosphamide (Cy), fludarabine (Flu) and anti-thymocyte globulin (ATG). Chimaerism at D + 17 showed engraftment of the 2 CB units and neutrophil recovery was reached at D + 31. After an Epstein–Barr virus (EBV) reactivation at D + 41, he developed lymphoproliferative disease involving the lungs and brain, which was successfully treated with chemotherapy and rituximab. Twelve months later, he presented with extensive chronic GvHD (cGvHD) that was responsive to steroids. He is now at 25 months after second transplant, in complete remission (CR), with full donor chimaerism of just one CB unit.

Patient 2

A 16-year-old girl, with severe aplastic anaemia, failing two courses of ciclosporin A, ATG and G-CSF, was transplanted with one UCB unit after myeloablative conditioning. At D + 30, she achieved neutrophil recovery with a full donor chimaerism. Secondary pancytopenia appeared with a cytomegalovirus (CMV) reactivation. After infection control and G-CSF, she had no marrow recovery with a mixed chimaerism (37% donor), leading to the decision to perform a second transplantation. Conditioning included Cy, Flu and total body irradiation (TBI). Eighty-one days after the first transplant, she received 2 UCB units, achieving engraftment at D + 27. An acute GvHD (aGvHD) grade-II and limited cGvHD were treated with steroids. She is now 12 months after the second transplant with complete donor chimaerism of one CB unit.

Patient 3

A 13-year-old boy, diagnosed with acute myeloid leukaemia (AML) with monosomy 7, was referred for an UCBT after myeloablative conditioning. At D + 19, a toxoplasmosis infection was diagnosed involving lungs and brain, and treated with sulfadiazine and pyrimethamine. At D + 46, with no signs of myeloid recovery, a BM aspirate confirmed GF, and the decision to perform a second transplant was taken. Following conditioning with Cy, Flu and ATG, 2 UCB units were infused 75 d after the first transplant. Engraftment was achieved on D + 20, with complete donor chimaerism. At D + 40, he developed grade-II aGVHD, which was treated with steroids. Later, a CMV reactivation was controlled with Foscarnet, and an extensive cGvHD responded to steroids. He is now 12 months after the second transplant, in CR and with full donor chimaerism of one CB unit.

Patient 4

A 5-year-old boy underwent a UCBT for a promyelocytic leukaemia t(15;17) in second CR. Considering the history of a previous autologous transplant and a venooclusive disease after gentuzumab, a reduced-intensity conditioning (RIC) was given. At D + 12, he showed an increase in lymphocyte counts, concomitant to CMV infection. Chimaerism performed that day showed 100% of recipient cells, consequently immunosuppression was reduced and stopped. At D + 61, a BM aspirate confirmed GF. Decision was taken for a second HSCT, with conditioning with Flu, Cy and TBI. At D + 76 after the first transplant he received 2 UCB units. Neutrophil recovery was achieved at D + 18, with full donor chimaerism. Concomitantly, he developed grade-II aGVHD, with evolution to a Grade-IV aGVHD, complicated by an adenovirus infection. Despite all immunosuppressive and antiviral treatment, he died on D + 46 after the second transplant.


Second allogeneic transplants using the same or a different donor are alternative treatments for early GF for patients undergoing a previous allogeneic HSCT. Although associated with a high treatment-related mortality, studies that used less intense conditioning regimens were able to reduce its toxicity (Storb et al, 1987; Ohwada et al, 2004). We decided to perform a second transplant using an RIC in our patients with GF. The feasibility of a second transplant also depends on a rapid work up for a second donor. In these situations, CB is easily available when compared with other unrelated HSCT sources and, more importantly, they can be obtained more quickly. Barker et al (2002) found that it took a median of 29 more days to identify an unrelated BM donor than an UCB unit (Barker et al, 2002). Because of the urgent situation for these four patients, a median of 15 d only was taken between the decision to perform a second transplant and the graft infusion. To circumvent the cell dose problem observed with a single CB unit (Gluckman et al, 1997; Gluckman et al, 2004), we used two CB units. In recent years, studies considering the use of two CB units have been published, aiming to increase cell dose mainly in adult patients and so increasing the probability of engraftment (Barker et al, 2005). Whether transplantation of 2 UCB units improves engraftment compared with a single unit is not yet known. Barker et al (2005) showed in a study of 23 patients, that 21 evaluable patients engrafted in a median time of 23 d, which is significantly higher than the reported rate for single CB units. Recent studies showed that stem cells from both CB units initially contribute to engraftment but, in the majority of cases (Weinreb et al, 1998; Ohwada et al, 2004; Barker et al, 2005), engraftment is sustained predominantly by just one unit, as was also found in our patients. The mechanisms leading this phenomenon are not well elucidated, but some authors suggest that there may be an immunological mechanism facilitating this process (Barker et al, 2005; Nauta et al, 2005). In conclusion, second transplant using two cord blood units after RIC to treat early GF seems to be a promising procedure.