Donor and recipient plasma follistatin levels are associated with acute GvHD in Blood and Marrow Transplant Clinical Trials Network 0402

Follistatin is an angiogenic factor elevated in the circulation after allogeneic hematopoietic cell transplantation (HCT). Elevations in follistatin plasma concentrations are associated with the onset of and poor survival after acute graft versus host disease (aGVHD). Using data from the Blood and Marrow Transplant Clinical Trials Network 0402 study (n=247), we sought to further quantify the longitudinal associations between plasma follistatin levels in transplant recipients, as well as baseline HCT donor follistatin levels, and allogeneic HCT outcomes. Higher recipient baseline follistatin levels were predictive of development of aGVHD (P=0.04). High donor follistatin levels were also associated with the incidence of aGVHD (P<0.01). Elevated follistatin levels on day 28 were associated with the onset of grade II–IV aGVHD prior to day 28, higher one-year non-relapse mortality, (NRM), and lower overall survival (OS). In multivariate analyses, individuals with follistatin levels >1088 pg/mL at day 28 had a four-fold increased risk for NRM (RR=4.3, 95% CI 1.9–9.9, P<0.01) and a nearly three-fold increased overall risk for mortality (RR=2.8, 95% CI 1.5–5.2, P<0.01). Given the multiple roles of follistatin in tissue inflammation and repair, and the confirmation that this biomarker is predictive of important HCT outcomes, the pathobiology of these relationships need further study.

Upper GI GVHD: similar outcomes to other grade II graft-versus-host disease

The significance of upper gastrointestinal tract (UGI) acute GVHD (aGVHD) compared with other grade II aGVHD is not clearly defined. We compared the outcomes of patients with grade II aGVHD with or without biopsy-proven UGI involvement in three groups: grade II aGVHD without UGI (n=178), grade II aGVHD with UGI and other sites (n=102) and isolated UGI aGVHD (n=32). The overall response (ORR) to steroids at day 28 differed among the three groups (76, 67 and 91%, respectively, P=0.01), but was only marginally different in direct comparison with those without or with UGI aGVHD (P=0.07) or with isolated UGI aGVHD (P=0.06). In multivariate analysis, as compared with grade II aGVHD patients without UGI involvement, those with UGI involvement and those with isolated UGI aGVHD had similar risks of chronic GVHD, relapse and non-relapse mortality and similar disease-free survival and overall survival. Our data suggest that patients with UGI aGVHD have similar outcomes as those without UGI involvement, supporting the view that UGI aGVHD should still be included as a grade II-defining event.

CD56dimCD57+NKG2C+ NK cell expansion is associated with reduced leukemia relapse after reduced intensity HCT

We have recently described a specialized subset of human natural killer (NK) cells with a CD56^dimCD57⁺NKG2C⁺ phenotype that expand specifically in response to cytomegalovirus (CMV) reactivation in hematopoietic cell transplant (HCT) recipients and exhibit properties characteristic of adaptive immunity. We hypothesize that these cells mediate relapse protection and improve post-HCT outcomes. In 674 allogeneic HCT recipients, we found that those who reactivated CMV had lower leukemia relapse (26% [17–35%], p=0.05) and superior disease-free survival (DFS) (55% [45–65%] p=0.04) 1 year after reduced intensity conditioning (RIC) compared to CMV seronegative recipients who experienced higher relapse rates (35% [27–43%]) and lower DFS (46% [38–54%]). This protective effect was independent of age and graft-versus-host disease (GvHD) and was not observed in recipients who received myeloablative (MA) regimens. Analysis of the reconstituting NK cells demonstrated that CMV reactivation is associated with both higher frequencies and greater absolute numbers of CD56^dimCD57⁺NKG2C⁺ NK cells, particularly after RIC HCT. Furthermore, expansion of these cells at 6 months post-transplant independently trended toward a lower 2-year relapse risk. Together, our data suggest that the protective effect of CMV reactivation on post-transplant relapse is in part driven by adaptive NK cell responses.

Hemorrhagic cystitis after allogeneic hematopoietic cell transplantation: risk factors, graft source and survival

Although hemorrhagic cystitis (HC) is a common complication of allogeneic hematopoietic cell transplantation (alloHCT), its risk factors and effects on survival are not well known. We evaluated HC in a large cohort (n=1321, 2003-2012) receiving alloHCT from all graft sources, including umbilical cord blood (UCB). We compared HC patients with non-HC (control) patients and examined clinical variables at HC onset and resolution. Of these 1321 patients, 219 (16.6%) developed HC at a median of 22 days after alloHCT. BK viruria was detected in 90% of 109 tested HC patients. Median duration of HC was 27 days. At the time of HC diagnosis, acute GVHD, fever, severe thrombocytopenia and steroid use were more frequent than at the time of HC resolution. In univariate analysis, male sex, age <20 years, myeloablative conditioning with cyclophosphamide and acute GVHD were associated with HC. In multivariate analysis, HC was significantly more common in males and HLA-mismatched UCB graft recipients. Severe grade HC (grade III-IV) was associated with increased treatment-related mortality but not with overall survival at 1 year. HC remains hazardous and therefore better prophylaxis, and early interventions to limit its severity are still needed.

Association between genetic variants in adhesion molecules and outcomes after hematopoietic cell transplants

Allogeneic hematopoietic cell transplant (HCT) is associated with a high morbidity and mortality. Adhesion molecules play an important role in endothelial activation and initiation of inflammatory response. We hypothesized that single nucleotide polymorphisms (SNPs) in the endothelial molecules may contribute to heterogeneity in HCT outcomes. We evaluated the association of 4 SNPs in ICAM1 (rs5498), PECAM1 (rs668 and rs1131012) and SELL (rs2229569) genes with acute and chronic graft-versus-host disease (GvHD) and those experiencing transplant-related mortality (TRM) within 1 year among 425 allogeneic HCT recipient-donor pairs. Using a Fine and Gray proportional hazards model to evaluate the association between genetic variants and clinical outcomes, after adjustment for recipient age, race, diagnosis, disease status, gender mismatch, cytomegalovirus serostatus, gender, donor type, conditioning regimen and year of transplant, only rs5498 in the ICAM1 gene among both recipients and donors was associated with a decreased risk of TRM (P ≤ 0.02). None of the SNPs were associated with acute or chronic GvHD risk. These findings suggest that genetic variants in the vascular adhesion molecules may be used to identify patients at high risk for TRM.

Factors predicting single-unit predominance after double umbilical cord blood transplantation

Double umbilical cord blood transplantation (dUCBT), developed as a strategy to treat larger patients with hematologic malignancies, frequently leads to the long-term establishment of a new hematopoietic system maintained by cells derived from a single UCB unit. However, predicting which unit will predominate has remained elusive. This retrospective study examined risk factor associated with unit predominance in 262 patients with hematologic malignancies who underwent dUCBT with subsequent hematopoietic recovery and complete chimerism between 2001–2009. Dual chimerism was detected at day 21–28, with subsequent single chimerism in 97% of cases by day +100 and beyond. Risk factors included nucleated cell dose, CD34+ and CD3+ cell dose, colony forming units-granulocyte macrophage dose, donor-recipient human leukocyte antigen (HLA) match, sex and ABO match, order of infusion, and cell viability. In the myeloablative setting, CD3+ cell dose was the only factor associated with unit predominance (OR 4.4, 95%CI, 1.8–10.6; p<0.01), but in the non-myeloablative setting, CD3+ cell dose (OR 2.1, 95%CI, 1.0–4.2; p=0.05) and HLA match (OR 3.4, 95%CI, 1.0–11.4; p=0.05) were independent factor associated with unit predominance. Taken together, these findings suggest that immune reactivity plays a role in unit predominance and should be considered during graft selection and graft manipulation.

Reduced-intensity hematopoietic cell transplantation in older patients with AML/MDS: umbilical cord blood is a feasible option for patients without HLA-matched sibling donors

Umbilical cord blood (UCB) has increased access to hematopoietic cell transplantation (HCT) for patients without HLA-matched sibling donors (MSD). We compared outcomes of HCT using MSD (N=38) or UCB (N=60) among older patients (age ≥ 55 years) with AML or myelodysplastic syndromes (MDS). All patients received a reduced intensity regimen consisting of CY, fludarabine and 200 cGy TBI. Median age at HCT was 63 years for MSD and 61 years for UCB recipients. Among UCB recipients, 95% received two UCB units and 88% received 1-2 locus HLA-mismatched units to optimize cell dose. OS at 3-years was 37% for MSD and 31% for UCB recipients (P=0.21). On multivariate analysis, donor source (MSD vs UCB) did not impact risks of OS, leukemia-free survival and relapse or treatment-related mortality. UCB is feasible as an alternative donor source for reduced-intensity conditioning HCT among older patients with AML and MDS who do not have a suitable MSD.

Health behaviors and cancer screening practices in long-term survivors of hematopoietic cell transplantation (HCT): a report from the BMT Survivor Study

Patients undergoing HCT are at increased risk of chronic health conditions, including second malignant neoplasms and cardiovascular disease. Little is known about health behaviors and cancer screening practices among HCT survivors that could moderate the risk of these conditions. The BMTSS examined health behaviors and cancer screening practices in individuals who underwent HCT between 1976 and 1998, and survived 2+ years. Health behavior was deemed high-risk if an individual was a current smoker and if they reported risky alcohol intake (≥4 drinks/day [males], ≥ 3 drinks/day [females]) on days of alcohol consumption. Cancer screening assessment was per American Cancer Society recommendations. There were 1040 survivors: 42.7% underwent allogeneic HCT; 43.8% were female; median time from HCT: 7.4 years (range 2.0–27.7 years). Median age at study participation: 43.8 years (range 18.3–73.0 years). Multivariate regression analysis revealed younger age (<35 years) at study participation (Odds Ratio [OR]=4.7; p<0.01) and lower education (<college: OR=2.1; p<0.01) to be significantly associated with high-risk behavior. Survivors were significantly less likely to report high-risk behavior (OR=0.5; p<0.01), and more likely to have had a screening mammogram (OR=2.8; p=0.05) when compared to gender-matched sibling controls (N=309).

Comparative analysis of BU and CY versus CY and TBI in full intensity unrelated marrow donor transplantation for AML, CML and myelodysplasia

We retrospectively compared clinical outcomes in 1593 T-replete unrelated donor (URD) marrow transplant recipients with AML, MDS and CML who received myeloablative conditioning regimens of either BU and CY (BuCy), standard-dose Cy/TBI (1000-1260 cGy) or high-dose Cy/TBI (1320-1500 cGy). Subjects were drawn from patients transplanted between 1991 and 1999 facilitated by the National Marrow Donor Program. Patients who received high-dose Cy/TBI regimens were slightly younger, more likely to receive a mismatched transplant and to have intermediate or advanced disease compared with patients in the BuCy or standard-dose TBI group. Neutrophil recovery was significantly higher in the standard-dose CY/TBI group compared with the high-dose Cy/TBI or BuCy group. Patients who received the high-dose Cy/TBI regimen had an increased risk of developing grades III-IV aGVHD when compared with the control group who received BuCy (P = 0.011). OS, disease-free survival (DFS), TRM and relapse were not significantly different between any of the regimens. We conclude that BuCy, standard-dose and high-dose Cy/TBI regimens have equivalent efficacy profiles for OS, DFS, TRM and relapse risk in patients undergoing T-replete URD marrow transplantation for AML, CML and MDS.

Allogeneic hematopoietic cell transplant for multiple myeloma: Comparative results of planned therapy versus salvage therapy

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Background: Despite advances in therapy for multiple myeloma, the disease remains incurable using chemotherapy or immune-modulating agents alone. Several newer hematopoietic cell transplant (HCT) strategies including tandem HCT, and non- myeloablative (NMA) regimens have reported encouraging results. However, the appropriate timing for utilizing these strategies is not clear. Methods: We report outcomes in 51 patients with multiple myeloma who received an allogeneic HCT; either as salvage therapy (after failing a prior autologous HCT), n= 15 or as planned therapy, n= 36, between the years 1996 and 2008 at University of Minnesota. Results: Patients in salvage therapy group were significantly older than in planned therapy group (median age 58 versus 49 years) and had a longer interval from diagnosis to transplant (median 47 versus 10 months). Forty four patients received a HCT from a HLA-identical sibling. Five received umbilical cord blood (four in salvage therapy, one in planned therapy group) and two received unrelated donor HCT (one in each group). Thirteen patients in planned therapy group underwent a tandem transplant (planned autologous followed by NMA sibling HCT). All patients in salvage therapy group, and 50% in planned therapy group received NMA HCT. Patients in salvage therapy group were more heavily pre-treated, all having failed a prior autologous HCT. Complete response was seen in 34% versus 47% of recipients in the two groups, respectively. After a median follow-up of 24 and 41 months, similar relapse was seen, but transplant related mortality (TRM) was significantly higher in salvage therapy group, leading to significantly lower two year survival and disease free survival (DFS) in salvage group. Conclusions: Good overall survival and low transplant related mortality was seen in patients undergoing a planned allogeneic transplant. In heavily pre-treated patients, receiving allogeneic HCT as salvage therapy, despite lower relapse, the high TRM led to lower survival.

[Table: see text]

No significant financial relationships to disclose.

Allo-hematopoietic cell transplantation for Ph chromosome-positive ALL: impact of imatinib on relapse and survival

The utility of imatinib in either the pre- or post-transplant period for Ph chromosome-positive (Ph+) ALL is uncertain. In addition, there have been recent concerns regarding imatinib and cardiac toxicity. We investigated the outcome of 32 patients with Ph+ ALL who received an allo-hematopoietic cell transplant (HCT) at the University of Minnesota between 1999 and 2006. The median age at HCT was 21.9 years (range: 2.8-55.2). All patients were conditioned with CY and TBI. GVHD prophylaxis was CsA based. Of the 32 patients, 15 received imatinib therapy pre- or post-HCT (imatinib group) and 17 patients received either no imatinib (n=11) or only after relapse (n=6) (non-imatinib group). Overall survival, relapse-free survival and relapse at 2 years was 61, 67 and 13% for the imatinib group as compared with 41, 35 and 35% for the non-imatinib group (P=0.19, 0.12 and 0.20, respectively). Cardiac toxicity and TRM at 2 years were similar between groups. Thus, patients treated with imatinib in either the pre- or post-transplant setting had trends toward improved outcomes and no increase in cardiac toxicity. We suggest that imatinib be included in the peri-transplant management of all patients with Ph+ ALL.

Hematopoietic cell transplantation (HCT) for acute lymphoblastic leukemia (ALL): 25-year experience at the University of Minnesota

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Background: HCT is frequently used for management of ALL. Methods: We reviewed the records of 623 consecutive patients (63% male, median age 13 years) treated with myeloablative TBI-containing conditioning and either autologous or allogeneic transplantation between 1980 and 2005 at the University of Minnesota. Donor types were autologous (34%), related (45%), unrelated (16%) or cord (11%). Disease status at transplant was CR1 (24%), CR2 (50%), CR3 (18%) and relapse (8%). Univariate and multivariate analyses were performed for clinical endpoints including overall survival (OS), progression free survival (PFS), relapse, treatment-related mortality (TRM), and Grades II-IV acute and chronic graft versus host disease (GVHD). Results: Median follow-up among survivors was 8.3 years (1.0–22.9). The estimated incidence of acute GVHD was 42% and chronic GVHD was 16%. At 5 years, OS, PFS, and relapse were estimated at 29%, 26%, and 43% respectively. 5-year OS for each group: autologous (17%, 12–22%), related (35%, 29–41%), matched unrelated (42%, 29–55%), mismatched unrelated (21%, 11–33%), and cord blood (46%, 33–59%). TRM at 2 years was 28%. Multivariate analysis for OS, PFS, relapse and TRM for donor type is shown ( Table ). Acute GVHD was more frequent with unrelated donors (p<0.01) but similar for related donors and cords. Presence of acute GVHD led to improved PFS (RR 0.6, 0.4–0.7, p<0.01) and decreased relapse (RR 0.5, 0.3–0.8, p<0.01) at 1 year. 5-year OS improved significantly from 1980–1984 (28%, 20–37%) to 2000–2005 (45%, 33–56%), p < 0.01. Conclusions: Allogeneic HCT results in a durable PFS, although TRM is increased with unrelated mismatched donors. As expected, autologous HCT results in increased relapse rates. Despite significant mismatch, umbilical cord HCT led to similar OS, PFS, relapse, TRM and chronic GVHD compared to related donor HCT. Development of acute GVHD decreases relapse, resulting in improved PFS.

No significant financial relationships to disclose.

[Table: see text]

Difficult stem cell mobilization despite adequate CD34+ cell dose predicts shortened progression free and overall survival after autologous HSCT for lymphoma

Hematopoietic growth factors alone or in combination with myelosuppressive chemotherapy are used to mobilize peripheral blood stem cells for autologous transplantation. To identify characteristics of successful mobilization with granulocyte colony-stimulating factor (G-CSF) alone and to study the impact of immediate chemotherapy mobilization following G-CSF mobilization, we treated 175 chemotherapy sensitive lymphoma patients with G-CSF (G) mobilization and leukapheresis followed by chemotherapy plus G-CSF (CG) mobilization and leukapheresis and then autologous transplantation. Patients with stage I/II disease at diagnosis and < or =5 years from diagnosis were more likely to mobilize successfully with G-CSF alone (G). CG mobilization led to superior stem cell yields compared to the preceding mobilization with G (median 2.37 vs 1.37 ( x 10(6)CD34+ cells/kg); P<0.0001). Patients (n=58, 33%) with successful G-CSF mobilization (> or =2 x 10(6) CD34+ cells/kg) had quicker platelet recovery and improved progression free and overall survival compared to patients who had adequate collection only after chemotherapy mobilization or to those who failed to collect an adequate graft with either type of mobilization. The poor clinical outcome of patients with difficult mobilization using either method identifies them as a high-risk group who might benefit from alternative therapies.

Fludarabine vs cladribine plus busulfan and low-dose TBI as reduced intensity conditioning for allogeneic hematopoietic stem cell transplantation: a prospective randomized trial

Purine analogs are often used for conditioning preceding allogeneic hematopoietic stem cell transplantation (HCT). We prospectively tested fludarabine (Flu) 40 mg/m(2)/day x 5 days vs cladribine (Clad) 10 mg/m(2)/day x 5 days plus oral busulfan (1 mg/kg q6 h x 2 days) and total body irradiation 200 cGy in 32 recipients of matched sibling and unrelated donor (URD) HCT. Patients were similar in age (median 52 years), diagnosis, extensive pre-HCT therapy (56 vs 63%), and high-risk disease status (81 vs 93%). Neutrophil engraftment was prompt (median 11 vs 12 days), but early graft failure using Clad halted randomization. Platelet recovery was prompt (median Flu 18 vs Clad 24 days). Graft-versus-host disease (GVHD) after Flu vs Clad was similar; (acute grade II/IV 56 vs 69%, P=0.26; chronic 50 vs 31%, P=0.27). Nonrelapse mortality (Flu 25 vs Clad 38%, P=0.47) and progression-free survival at 3 years were similar as well. Multivariate analyses showed slightly, but not significantly lower relative risk (RR) of neutrophil engraftment with Clad (RR 0.6 (95% CI 0.2-1.3) P=0.16) and with URD RR 0.4 (0.2-1.0) P=0.04). Older patients with advanced hematologic malignancies achieve satisfactory outcomes using either of these reduced intensity conditioning regimens.

Alveolar hemorrhage following allogeneic hematopoietic cell transplantation using reduced-intensity conditioning

Allogeneic hematopoietic cell transplantation (HCT) using reduced-intensity conditioning (RIC) has lower morbidity and mortality compared to transplantation using myeloablative conditioning (MAC). The syndrome of alveolar hemorrhage, a life-threatening pulmonary complication of HCT, has not been well described after RIC HCT. We reviewed prospectively collected data on 206 RIC and 1112 MAC HCT performed between 1995 and 2004 to study the impact of conditioning regimen on the clinical features and outcome of alveolar hemorrhage. Alveolar hemorrhage occurred in 18 RIC HCT recipients (cumulative incidence 8% (95% confidence intervals (CI), 5-11%)) and 85 MAC HCT recipients (cumulative incidence 7% (95% CI, 6-8%), P = 0.56). The clinical presentation of hemorrhage in both cohorts was similar. Survival at 60 days from the onset of hemorrhage was 28% (95% CI, 7-49%) for RIC group compared to 26% (95% CI, 17-35%) after MAC HCT (P = 0.56). Reducing the intensity of preparative regimen does not protect against post transplant alveolar hemorrhage. Alveolar hemorrhage occurring after RIC or MAC HCT has similar incidence, clinical presentation, and associated high mortality.

Prevalence of conception and pregnancy outcomes after hematopoietic cell transplantation: report from the Bone Marrow Transplant Survivor Study

We conducted a retrospective study to describe the magnitude of compromise in reproductive function and investigate pregnancy outcomes in 619 women and partners of men treated with autologous (n=241) or allogeneic (n=378) hematopoietic cell transplantation (HCT) between 21 and 45 years of age, and surviving 2 or more years. Median age at HCT was 33.3 years and median time since HCT 7.7 years. Mailed questionnaires captured pregnancies and their outcomes (live birth, stillbirth, miscarriage). Thirty-four patients reported 54 pregnancies after HCT (26 males, 40 pregnancies; eight females, 14 pregnancies), of which 46 resulted in live births. Factors associated with reporting no conception included older age at HCT (> or =30 years: odds ratio (OR)=4.8), female sex (OR=3.0), and total body irradiation (OR=3.3). Prevalence of conception and pregnancy outcomes in HCT survivors were compared to those of 301 nearest-age siblings. Although the risk for not reporting a conception was significantly increased among HCT survivors (OR=36), survivors were not significantly more likely than siblings to report miscarriage or stillbirth (OR=0.7). Although prevalence of conception is diminished after HCT, if pregnancy does occur, outcome is likely to be favorable. Patients should be counseled prior to transplant regarding strategies to preserve fertility.

Results of autologous and allogeneic hematopoietic cell transplant therapy for multiple myeloma

We compared the results of autologous and allogeneic peripheral blood hematopoietic cell transplant (HCT) in 87 patients with multiple myeloma using myeloablative preparative regimen. Autologous transplant (n=70) led to a lower 100-day transplant-related mortality (TRM) of 4% [0-9%] compared to 18% [0-36%] in allogeneic recipients (P=0.02). More frequent complete responses were seen in allogeneic recipients (64% [37-91%] vs 34% [23-45%] in autologous recipients, P=0.09). In autologous recipients, survival at 1 year was 86% [80-95%] and, it fell to 50% [47-75%] at 4 years, whereas in allogeneic recipients, survival at 1 and 4 years remained at 64% [40-87%]. In patients surviving more than one year, 4-year survival was superior in allogeneic (100%) vs autologous recipients (58% [41-75%], P=0.02). A trend toward higher relapse was seen in autologous transplant patients (73% [55-90%] vs 37% [11-63%] in allogeneic transplant patients, P=0.1). We observed good tolerance of myeloablative conditioning regimen followed by either autologous or allogeneic transplant. Although autologous HCT is associated with lower TRM, allogeneic HCT has acceptable TRM, and is more likely to provide a sustained response. Allogeneic HCT may be suitable in younger patients, soon after diagnosis, and in those with chemosensitive disease.

Autologous stem cell transplantation in multiple myeloma patients <60 vs >/=60 years of age

The role of autologous stem cell transplantation (AuSCT) in older multiple myeloma patients is unclear. Using data from the Autologous Blood and Marrow Transplant Registry, we compared the outcome of 110 patients >/=the age of 60 (median 63; range 60-73) years, undergoing AuSCT with that of 382 patients <60 (median 52; range 30-59) years. The two groups were similar except that older patients had a higher beta(2)-microglobulin level at diagnosis (P=0.016) and fewer had lytic lesions (P=0.007). Day 100 mortality was 6% (95% confidence interval 4-9) and 1-year treatment-related mortality (TRM) was 9% (6-13) in patients <60 years, compared with 5% (2-10) and 8% (4-14), respectively, in patients >/=60 years. The relapse rate, progression-free survival (PFS) and overall survival (OS) in the two groups were also similar. Multivariate analysis of all patients identified only an interval from diagnosis to AuSCT >12 months and the use of two prior chemotherapy regimens within 6 months of AuSCT as adverse prognostic factors. Our results indicate that AuSCT can be safely performed in selected older patients: the best results were observed in patients undergoing AuSCT relatively early in their disease course.

IL-2-based immunotherapy after autologous transplantation for lymphoma and breast cancer induces immune activation and cytokine release: a phase I/II trial

We determined the safety, immune activating effects, and potential efficacy of i.v. infusion of ex vivo interleukin-2 (IL-2) activated natural killer (NK) cells (part I) or IL-2 boluses (part II) during daily s.c. IL-2 administration following hematopoietic recovery from autologous transplantation. In all, 57 patients with relapsed lymphoma (n=29) or metastatic breast cancer (n=28) were enrolled. In part I of the study, 34 patients were enrolled at three dose levels of ex vivo IL-2-activated NK cells. Lymphaphereses were performed on days 28 and 42 of s.c. IL-2 administration. Following overnight ex vivo IL-2 activation of the pheresis product, the cells were reinfused the following day. In part II, 23 patients were enrolled at three dose levels of supplemental i.v. IL-2 bolus infusions, given on days 28 and 35 during s.c. IL-2 administration. Toxicities were generally mild, and no patient required hospitalization. Lytic function was markedly enhanced for fresh peripheral blood mononuclear cells (PBMNCs) obtained 1 day postinfusion of either IL-2-activated cells or IL-2 boluses. IL-2 boluses transiently increased the levels of IL-6, IFN-gamma, TNF-alpha and IL1-beta, with increases in IL-6 and IFN-gamma being dose dependent. A total of 37 patients (19 patients with lymphoma, 18 with breast cancer) treated with an optimum dose of post-transplant immunotherapy (defined as having received 1.75 x 10(6) IU/m(2)/day of s.c. IL-2 plus at least one of the planned ex vivo IL-2-activated cell infusions/IL-2 boluses) could be matched with controls from the Autologous Blood and Marrow Transplant Registry database. The matched-pairs analysis demonstrated no improvement in disease outcomes of survival and relapse. We conclude that IL-2-activated cells/IL-2 boluses can be safely administered, generate PBMNCs with enhanced cytotoxicity against NK-resistant targets, and increase cytokine levels. With this dose and schedule of administration of IL-2, no improvement in patient disease outcomes was noted. Alternative strategies will be needed to exploit the immunotherapeutic potential of IL-2-activated NK cells.

Cytomegalovirus enteritis among hematopoietic stem cell transplant recipients

Cytomegalovirus (CMV) is a cause of enteritis associated with hematopoietic stem cell transplantation (HSCT), but the natural history is rarely studied and hence poorly understood. CMV infection at this end-organ site is notably less frequent than is pneumonitis. To evaluate the spectrum of CMV enteritis after HSCT, we reviewed the database spanning 11.5 years of 2240 University of Minnesota transplantation patients for cases of gastrointestinal CMV. We identified 46 case-patients. The incidence of CMV enteritis at 2 years following HSCT averaged 2% over the 11.5-year study interval. The median time to diagnosis of CMV enteritis after HSCT was 91 days (range, 17-527 days). The methods used in diagnosis included histopathology (58%) and virology (61%). Viremia was detected in two thirds of patients with CMV prior to the diagnosis of enteritis. Most treatment regimens included ganciclovir. The overall survival rate was 35% at 2 years following the onset of enteritis.

Randomized clinical trial of ganciclovir vs acyclovir for prevention of cytomegalovirus antigenemia after allogeneic transplantation

Cytomegalovirus (CMV) disease remains a major cause of morbidity following allogeneic stem cell transplantation (SCT). In a prospective randomized trial, we tested prophylactic therapy with ganciclovir or acyclovir for patients at high risk of disease. Ninety-one CMV seropositive recipients of related (n = 53) and unrelated (n = 38) donor transplants were enrolled. All patients received intravenous (i.v.) ganciclovir 5 mg/kg every 12 h days -7 to -2, followed by acyclovir 10 mg/kg i.v. every 8 h from day -1 until neutrophil engraftment. Patients were then randomly assigned to either ganciclovir (n = 45) or acyclovir (n = 46) until day 100 post transplant. Any degree of antigenemia was treated with ganciclovir 5 mg/kg i.v. twice a day for 2 weeks, followed by 5 mg/kg i.v. each weekday for 6 weeks. At day 100, the cumulative incidence of antigenemia was 31% (95% CI 17-45%) for ganciclovir and 41% (95% CI 26-56%) (P = 0.22) for acyclovir prophylaxis, respectively. The assigned prophylaxis cohort did not predict for CMV antigenemia. The cumulative incidence of CMV disease at 12 months was 13% (95% CI 3-23%) and 17% (95% CI 6-28%) (P = 0.59) for the ganciclovir- and acyclovir-treated groups, respectively. An absolute neutrophil count (ANC) <or=1500 x 10(6)/l at randomization (P < 0.01) and grade II-IV acute graft-versus-host-disease (P = 0.01), but not the assigned prophylaxis cohort (P = 0.62), were independent risk factors for CMV disease. The incidence of fungal infections and renal insufficiency was similar across treatment groups; however, bacterial infections and secondary neutropenia occurred more frequently in the ganciclovir group. With our study powered to detect a 60% reduction in antigenemia with ganciclovir prophylaxis, we did not find a statistically significant difference between ganciclovir and acyclovir when used as part of an overall strategy for prevention of CMV antigenemia and disease in SCT, although fewer side-effects occurred with acyclovir treatment.

Acquired factor VII deficiency in hematopoietic stem cell transplant recipients

Acquired factor VII (FVII) deficiency in the absence of vitamin K deficiency, oral anticoagulant therapy, synthetic liver dysfunction, or DIC is rare, with only a handful of cases thus far reported. In the period from 1990 to 1996 we identified eight patients with acquired FVII deficiency, all of whom presented with prolongation of the prothrombin time (PT) in the first 2 weeks following stem cell transplantation (SCT). The mean plasma FVII clotting activity (FVII:c) was 22% (range 8-35%) with an approximately equivalent reduction in FVII antigen (FVII:Ag) level. Mean plasma levels of fibrinogen and factors II, V, IX, and X were normal. Protein C activity was significantly depressed in only one of the three patients in whom it was measured. Several patients experienced bleeding complications, and hemorrhage directly accounted for death in two cases. Veno-occlusive disease of the liver developed in three patients. We conclude that FVII deficiency should be considered in the differential diagnosis of prolonged PT in patients who have recently undergone SCT. The mechanism of this acquired deficiency state remains to be defined.

Low incidence of Epstein-Barr virus-associated posttransplantation lymphoproliferative disorders in 272 unrelated-donor umbilical cord blood transplant recipients

Umbilical cord blood (UCB) is being increasingly used for transplantation, but the ability of neonatal T cells to regulate Epstein-Barr virus (EBV)-associated lymphoproliferation is unknown. Because UCB transplantation (UCBT) is associated with a relatively low infused dose of donor T cells, frequent donor-recipient HLA disparity, and use of antithymocyte globulin during conditioning, we hypothesized that the risk of EBV-associated posttransplantation lymphoproliferative disorders (EVB-PTLD) after UCBT may be increased. To investigate the incidence of EBV-PTLD after UCBT, we analyzed 272 unrelated-donor UCBTs performed from August 1993 to December 1999 at Duke University Medical Center and the University of Minnesota. Five cases of EBV-PTLD were identified, with a cumulative incidence of 2% (95% confidence interval, 0.3%-3.7%) at 2 years. EBV-PTLD affected UCB recipients aged 1 to 49 years (median, 8 years), with 4 patients undergoing transplantation for leukemia and 1 for immunodeficiency. Patients received UCB grafts that were HLA matched (n = 1) or mismatched at 1 (n = 1) or 2 (n = 3) HLA loci. Diagnoses occurred at 4 to 14 months (median, 6 months) after UCBT, with 4 of 5 patients having preceding grade II to IV acute graft-versus-host disease and 1 being diagnosed at autopsy. Treatment of 4 patients consisted of withdrawal of immunosuppressive treatment and administration of rituximab, with 2 of 4 patients responding. Thus, the incidence of EBV-PTLD after unrelated-donor UCBT appears similar to that observed after transplantation using unrelated bone marrow (BM) and compares favorably with unrelated-donor T-cell-depleted BM transplantation. Because adoptive immunotherapy with donor lymphocytes is not an available option for recipients of unrelated-donor UCBT, new therapeutic strategies are needed, and rituximab appears promising.

Infections during mobilizing chemotherapy and following autologous stem cell transplantation

Autologous peripheral blood stem cells (PBSC), for transplantation following high-dose chemotherapy, are collected using regimens containing cytokines with or without chemotherapy. The added period of neutropenia prior to stem cell transplantation (SCT) in patients receiving chemotherapy mobilization may increase the risk of infections following transplantation. We studied the incidence of culture-positive infections in 107 consecutive patients who were divided into three groups, according to whether they experienced extended neutropenia during chemotherapy for stem cell mobilization as well as post autotransplant. All the patients received antibiotic prophylaxis and hematopoietic growth factors during neutropenia. The total duration of pre-transplant neutropenia differed among the three mobilization schemes (growth factors alone; one cycle; or two cycles of chemotherapy plus growth factor for mobilization) at 0, 6 and 18 days, respectively (median). However the post-autograft time to myeloid engraftment was similar at 10 days (median). The incidence of culture-proven infections in all three groups was similar. Using fluconazole for yeast prophylaxis, 40% patients developed gastrointestinal colonization with yeast, and the majority of speciated isolates were Candida glabrata. Bacteremia developed in 22% and 9% of patients with S. epidermidis and Gram-negative organisms, respectively, while 11% developed C. difficile-associated diarrhea. In conclusion, treatment using none, one or two cycles of mobilizing chemotherapy pre-transplant does not influence the overall incidence of infections among autologous SCT recipients. However, although post-transplant neutropenia is brief, infections remain a significant cause of morbidity.

Serious cardiac complications during bone marrow transplantation at the University of Minnesota, 1977-1997

Cardiac complications may result from high-dose chemotherapy or irradiation administered during the conditioning phase of bone marrow and blood stem cell transplantation (BMT). To assess the frequency of clinically serious cardiac toxicity related to the acute phase of BMT, we retrospectively examined life-threatening or fatal cardiotoxicity identified using the complications records of our transplant center clinical database. All serious cardiac toxicity events within 100 days of BMT except those attributable to septic shock, pneumonitis or multi-organ failure were reviewed. Of 2821 BMT patients at the University of Minnesota between 1977 and 1997, 26 were identified as having suffered major or fatal (n = 13) cardiotoxicity (0.9%, 19 adults and seven children). Rapidly progressive heart failure resulted in death of 11 patients, one patient had fatal pericardial tamponade, and one had an acute ventricular fibrillation arrest. The remaining 13 patients (50%) had life-threatening cardiotoxicity including four patients with pericardial tamponade and nine patients with cardiac arrhythmias. Overall, we observed that acute, major cardiotoxic events attributable to BMT are uncommon, occurring with a frequency of <1%. These data suggest that with appropriate pre-transplant clinical evaluation, high-dose cyclophosphamide and irradiation in the BMT preparative phase does not result in frequent, clinically relevant short-term cardiac toxicity.

Survival after transplantation of unrelated donor umbilical cord blood is comparable to that of human leukocyte antigen-matched unrelated donor bone marrow: results of a matched-pair analysis

Umbilical cord blood (UCB) is being increasingly used for hematopoietic stem cell transplantation and has been associated with a reduced incidence of severe graft-versus-host disease (GVHD). To further investigate the relative merits of unrelated donor UCB versus bone marrow (BM), a matched-pair analysis comparing the outcomes of recipients of 0 to 3 human leukocyte antigen (HLA)-mismatched UCB and HLA-A, B, DRB1-matched BM was performed. UCB patients, who received cyclosporine (CSA) and methylprednisolone (MP), were matched for age, diagnosis, and disease stage with BM patients, who received either methotrexate (MTX) and CSA (26 pairs) or T-cell depletion (TCD) and CSA/MP (31 pairs). Patients were predominantly children (median age, 5 years) undergoing transplantation for malignancy, storage diseases, BM failure, and immunodeficiency syndromes between 1991 and 1999. Although neutrophil recovery was significantly slower after UCB transplantation, the probability of donor-derived engraftment at day 45 was 88% in UCB versus 96% in BM-MTX recipients (P =.41) and 85% in UCB versus 90% in BM-TCD recipients (P =.32), respectively. Platelet recovery was similar in UCB versus BM pairs. Furthermore, incidences of acute and chronic GVHD were similar in UCB and BM recipients, with 53% of UCB versus 41% of BM-MTX recipients alive (P =.40) and 52% of UCB versus 56% of BM-TCD recipients alive at 2 years (P >.80), respectively. These data suggest that despite increased HLA disparity, probabilities of engraftment, GVHD, and survival after UCB transplantation are comparable to those observed after HLA-matched BM transplantation. Therefore, UCB should be considered an acceptable alternative to HLA-matched BM for pediatric patients.

Equivalent outcomes in patients with chronic myelogenous leukemia after early transplantation of phenotypically matched bone marrow from related or unrelated donors

PURPOSE

To determine if the favorable outcomes after transplantation of matched sibling donor bone marrow in patients with chronic myelogenous leukemia can be achieved using bone marrow from an HLA-A,B/DRB1-matched unrelated donor.

SUBJECTS AND METHODS

Between April 1983 and December 1997, 141 patients with chronic myelogenous leukemia in its first chronic phase received a bone marrow transplant from a matched sibling donor (n = 96) or an HLA-A,B/DRB1-matched unrelated donor (n = 45). The median age of matched sibling donor recipients was 38 years (range, 8 to 56 years) and of unrelated donor recipients was 35 years (range, 3 to 53 years; P = 0.03). The median follow-up was 6 years (range, 1 to 15 years) in matched sibling donor recipients and 5 years (range, 2 to 10 years) in unrelated donor recipients.

RESULTS

There was no significant difference in the 5-year survival rates of matched sibling donor recipients [58%; 95% confidence interval (CI), 48% to 68%] and unrelated donor recipients (53%; 95% CI, 39% to 67%; P = 0.4). Among patients who underwent transplantation within 1 year after diagnosis, the 5-year survival rate of matched sibling donor recipients (76%; 95% CI, 65% to 87%) was not significantly different (P = 0.5) from that of unrelated donor recipients (70%; 95% CI, 52% to 88%). In multiple regression analysis, longer time from diagnosis to transplantation, T-cell depletion, and grades III or IV graft versus host disease were independently associated with poorer survival. Transplantation of unrelated donor bone marrow was not associated with mortality (relative risk, 1.1; 95% CI, 0.6 to 2.1; P = 0.7).

CONCLUSIONS

Transplantation of bone marrow from a matched sibling donor or an HLA-A,B/DRB1-matched unrelated donor produces equivalent outcomes in patients with chronic myelogenous leukemia, particularly if the transplant takes place within 1 year after diagnosis.

Non-leukemic autologous reconstitution after allogeneic bone marrow transplantation for Ph-positive chronic myelogenous leukemia: extended remission preceding eventual relapse

Autologous reconstitution is the recovery of autologous hematopoietic function after failure of an allogeneic graft to establish sustained hematopoiesis either with or without preceding donor engraftment. We reviewed 9 years experience of the University of Minnesota and identified 10 of 291 patients who underwent allogeneic BMT for Ph-positive CML and developed non-leukemic autologous reconstitution. All patients received the same preparative regimen with cyclophosphamide and total body irradiation. Eight patients had a 6/6-antigen matched donor. Eight patients received their graft from an unrelated donor. In five cases the graft was T cell-depleted. Non-malignant autologous reconstitution initially manifested as mixed chimerism in nine of 10 patients and lasted for a median of 11 (3-41) months. Eight patients have relapsed and four are still alive. The two relapse-free patients have died 24 and 48 months post transplant. Of the four surviving patients, two are in interferon-induced cytogenetic remission at 53+ and 101+ months of follow-up. Autologous non-leukemic reconstitution is uncommon, but appears to be a distinct clinical syndrome, perhaps occurring more frequently after unrelated donor BMT. Although usually followed by relapse, relapse-free survival may be prolonged.

CMV antigenemia following bone marrow transplantation: risk factors and outcomes

Cytomegalovirus (CMV) infection remains a major problem in blood and bone marrow transplant (BMT) recipients. Recent efforts have been directed at prevention, early diagnosis, and treatment of CMV disease following BMT. Assay for CMV early antigen pp65 on circulating leukocytes has been shown to be sensitive, and specific in detecting early CMV infection. We examined the frequency, risk factors, and outcomes of a positive CMV antigen assay in 118 consecutive BMT patients. Forty-three (36%) of the 118 patients developed CMV antigenemia a median of 26 days post-BMT (range, -6 to 209 days). The incidence of antigenemia in autologous, related donor, and unrelated donor BMT recipients was 15%, 50%, and 48%, respectively (P < .01) and was lower in CMV-seronegative patients (19% versus 51% in seropositive patients; P < .01). Patients with grade II to IV acute graft-versus-host disease (GVHD) had 2.2 times the risk of antigenemia of patients with no or only limited GVHD (P = .03). Age at transplantation, underlying disease, CMV prophylaxis regimen, and GVHD prophylaxis regimen did not affect the risk of CMV antigenemia. Ten of the 43 antigenemic patients, all CMV-seropositive allogeneic BMT (alloBMT) recipients, developed CMV organ disease a median of 101 days (range, 28-283 daya) post-BMT. These data suggest that CMV-seropositive alloBMT patients are at highest risk for CMV antigenemia and for organ disease as well. CMV disease may occur before antigenemia is detectable in leukopenic patients and may also develop late post-BMT, even in patients still receiving antiviral prophylaxis. In high-risk groups, intensive surveillance continuing for more than 6 months after BMT may be indicated.

Matched-pair analysis of peripheral blood stem cells compared to marrow for allogeneic transplantation

We performed a case-control analysis of 42 patients with advanced leukemia or MDS comparing peripheral blood stem cell (PBSC) with marrow grafts (BMT) from HLA-matched sibling donors. PBSC were mobilized with G-CSF (7.5 microg/kg/day) and yielded a median of 6.7 x 10(6) CD34+ cells/kg (range, 1.6-15.0) and 2.7 x 10(8) CD3+ cells/kg (range, 1.1-7.1) vs marrow grafts with a median of 2.0 x 10(8) nucleated cells/kg (range, 1.8-2.2). Recovery was significantly faster after PBSCT compared to BMT, with a median of 17 (range, 12-26) vs 26 (range, 16-36) days, respectively, to neutrophils >0.5 x 10(9)/l (P < 0.01), and 22 (range, 12->60) vs 42 (range, 18->60) days, for platelet recovery (P < 0.01). Transplantation of >/=7 x 10(6) CD34+ cells/kg accelerated recovery to >20 x 10(9) l platelets; median 17 days (range, 12-19) vs 23 days (range, 17-36) for those receiving <7 x 10(6)/kg (P = 0.01). PBSC and marrow recipients had similar risks of grades II-IV or III-IV acute GVHD or extensive chronic GVHD (all P > 0.3). At 1 year after PBSCT and BMT, the risk of relapse was 41% and 32%, respectively (P = 0.47), and the probability of survival was 46% and 48%, respectively (P = 0.70). HLA-matched sibling PBSCT resulted in faster neutrophil and platelet engraftment compared to BMT, with no subsequent differences in acute or chronic GVHD, relapse or survival. A minimum of 7 x 10(6) CD34+ cells/kg in PBSC grafts may be required for very rapid platelet engraftment. Bone Marrow Transplantation (2000) 26, 723-728.

Response to thalidomide therapy in refractory chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) refractory to standard immunosuppressive therapy remains a major cause of morbidity and mortality after allogeneic bone marrow transplantation (BMT). Thalidomide may be effective in some patients with high-risk or refractory chronic GVHD. We report a single-institution study of thalidomide in 37 BMT patients with extensive chronic GVHD refractory to standard immunosuppressive therapy. Acute GVHD occurred in 34 (91%) of patients and evolved progressively into chronic GVHD in 23 (62%) patients. Thalidomide was added to standard immunosuppressive therapy a median of 11 months (range 0-105 months) after the diagnosis of chronic GVHD. Fourteen of 37 (38%) patients responded after introduction of thalidomide (one complete, 13 partial). Ten of 21 (46%) children and four of 16 (25%) adults responded. Responses were seen in eight of 17 (47%) recipients of related donor marrow and six of 20 (30%) recipients of unrelated donor marrow. Eight of 23 (34%) patients with progressive onset of chronic GVHD showed a response. There were no deaths among the responders. The remaining 23 patients (62%) did not respond and of these only two survive, one with progressive scleroderma, and the other with bronchiolitis obliterans. Chronic GVHD with associated infection (most commonly disseminated fungal infection) was a major contributor to mortality in all cases. Overall, after initiation of thalidomide, the 2-year Kaplan-Meier survival was 41% (95% C.I. 24%-59%). We conclude that thalidomide is a useful and well-tolerated therapy for patients with previously treated refractory chronic GVHD, including those with progressive onset of chronic GVHD, recipients of unrelated donor marrow, and children. Earlier introduction of thalidomide as an adjunct to standard immunosuppressive therapy may lead to more frequent responses and possible better survival.

The spectrum of Malassezia infections in the bone marrow transplant population

A consecutive series of 3044 patients who underwent BMT at the University of Minnesota over a 25 year period were reviewed for the post-transplant occurrence of infection caused by the yeast Malassezia furfur. Six patients, ranging in age from 1 to 54 years, developed Malassezia infections at a median of 59 days post transplant. Five patients were allogeneic transplant recipients; the remaining patient had undergone autologous transplantation. A spectrum of clinical manifestations of Malassezia infection was seen in these patients, including infections of mucosal surfaces and the skin, in addition to catheter-related fungemia. Unlike many of the other more common opportunistic fungal infections in immunocompromised patients, neutropenia and the use of broad-spectrum antimicrobials do not appear to be significant risk factors for Malassezia infections in the BMT population. In addition, disseminated fungal infection despite the presence of fungemia is uncommon. Lastly, the outcome of Malassezia infections in these patients, whether folliculitis, mucosal infection, or fungemia, appears to be quite favorable, in contrast to the poorer outcome with many other fungal infections in BMT patients. Catheter removal and discontinuation of intravenous lipids are important for a successful outcome in fungemic cases.

Increasing incidence of diffuse alveolar hemorrhage following allogeneic bone marrow transplantation: cryptic etiology and uncertain therapy

Diffuse alveolar hemorrhage (DAH) is a non-infectious pulmonary complication of bone marrow transplantation (BMT) with resultant high mortality. It reportedly occurs primarily in autologous recipients. We examined the incidence of DAH in our center in order to assess potential risk factors and develop preventive strategies. Between 1991 and 1997, 23 cases of DAH occurred in 922 adult patients (2.5%) receiving BMT for hematological malignancy. Strikingly, 12 cases occurred in 1997 with the majority in recipients of allogeneic matched sibling donor stem cells. Treatment with high-dose steroids, 250 mg to 2 g/day, in 15 patients led to transient improvement in 10 patients, but 21 of the 23 patients required mechanical ventilation. Mortality was high with 17 patients (74%) dying a median of 39 days (range 22-47) post transplant; a median of 17 days post onset of DAH (range 5-34). Six patients are alive with a median follow-up of 18 months (range 12-60). No recognizable alteration in supportive care, conditioning regimen, GVHD prophylaxis or cytokine usage was associated with this striking increase in the frequency of DAH after allografting. Further follow-up is required to establish whether this increase in the incidence of DAH in allogeneic transplantation is an isolated occurrence or an ongoing problem. If indeed there is a real increase in the incidence of this complication, then efforts need to be directed towards elucidating a possible cause or risk factors. We offer the possibility that a new unidentified infection, undetected by current microbiological tests might contribute to this striking increase in DAH. These data, while not establishing a cause, suggest a markedly augmented risk of DAH in allogeneic BMT. In addition, high-dose corticosteroids have only limited efficacy as therapy for DAH after allotransplantation. Further investigation into the pathogenesis of this syndrome is essential as is prompt and immediate consideration of DAH in all patients with respiratory compromise early after BMT.

Haematopoietic cell transplantation in patients with Fanconi anaemia using alternate donors: results of a total body irradiation dose escalation trial

Allogeneic haematopoietic cell transplantation (HCT) is the only therapeutic modality capable of correcting the haematologic manifestations of Fanconi anaemia (FA). However, HCT from alternative donors has been associated with poor survival. Between June 1993 and July 1998, 29 FA patients (median age 12.1 years; range 3.7-48.5 years) were enrolled in a prospective phase I-II dose escalation study. All patients were treated with cyclophosphamide 40 mg/kg, total body irradiation (TBI) 450 cGy or 600 cGy and antithymocyte globulin (ATG), followed by HCT from an alternative donor. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin A for 6 months, short course methylprednisolone (2 mg/kg/day) between days +5 and +19 and marrow T-cell depletion by counterflow elutriation. The probability of developing grade III-IV toxicity was 17% (95% CI 3-31%). For the 25 marrow recipients, the probability of neutrophil engraftment (ANC 0.5 x 109/l by day 45) was 63% (95% CI 42-82%). Probabilities of grade II-IV acute GVHD and chronic GVHD were 32% (95%CI 10-54%) and 0% respectively. With a median follow-up of 18 months, the probability of survival for the entire cohort at 1 year was 34% (95% CI 17-51%). The presence of lymphocyte somatic mosaicism [i.e. the presence of diepoxybutane (DEB)-insensitive cells] was associated with a significantly increased risk of graft failure. Disappointingly, the use of higher dose TBI and post-transplant ATG did not improve engraftment. More effective peritransplant immunosuppression, especially in FA patients with somatic mosaicism, was required to overcome the barrier of graft rejection. New conditioning regimens adapted to each individual's alkylator sensitivity are needed to improve the outcome of alternative donor HCT for FA.