Prolonged sirolimus administration after allogeneic hematopoietic cell transplantation is associated with decreased risk for moderate-severe chronic graft-versus-host disease

Effective pharmacological strategies employed in allogeneic hematopoietic cell transplantation should prevent serious chronic graft-versus-host disease and facilitate donor-recipient immune tolerance. Based on demonstrated pro-tolerogenic activity, sirolimus (rapamycin) is an agent with promise to achieve these goals. In a long-term follow-up analysis of a randomized phase II trial comparing sirolimus/tacrolimus versus methotrexate/tacrolimus for graft-versus-host disease prevention in matched sibling or unrelated donor transplant, we examined the impact of prolonged sirolimus administration (≥ 1 year post-transplant). Median follow-up time for surviving patients at time of this analysis was 41 months (range 27–60) for sirolimus/tacrolimus and 49 months (range 29–63) for methotrexate/tacrolimus. Sirolimus/tacrolimus patients had significantly lower National Institutes of Health Consensus moderate-severe chronic graft-versus-host disease (34% vs. 65%; P=0.004) and late acute graft-versus-host disease (20% vs. 43%; P=0.04). While sirolimus/tacrolimus patients had lower prednisone exposure and earlier discontinuation of tacrolimus (median time to tacrolimus discontinuation 368 days vs. 821 days; P=0.002), there was no significant difference in complete immune suppression discontinuation (60-month estimate: 43% vs. 31%; P=0.78). Prolonged sirolimus administration represents a viable approach to mitigate risk for moderate-severe chronic and late acute graft-versus-host disease. Further study of determinants of successful immune suppression discontinuation is needed.     

High-risk HLA alleles for severe acute graft-versus-host disease and mortality in unrelated donor bone marrow transplantation

HLA molecules play an important role for immunoreactivity in allogeneic hematopoietic stem cell transplantation. To elucidate the effect of specific HLA alleles on acute graft-versus-host disease, we conducted a retrospective analysis using 6967 Japanese patients transplanted with T-cell-replete marrow from an unrelated donor. Using unbiased searches of patient and donor HLA alleles, patient and/or donor HLA-B*51:01 (patient: HR, 1.37, P<0.001; donor: HR, 1.35, P<0.001) and patient HLA-C*14:02 (HR, 1.35, P<0.001) were significantly associated with an increased risk of severe acute graft-versus-host disease. The finding that donor HLA-C*14:02 was not associated with severe acute graft-versus-host disease prompted us to elucidate the relation of these high-risk HLA alleles with patient and donor HLA-C allele mismatches. In comparison to HLA-C allele match, patient mismatched HLA-C*14:02 showed the highest risk of severe acute graft-versus-host disease (HR, 3.61, P<0.001) and transplant-related mortality (HR, 2.53, P<0.001) among all patient mismatched HLA-C alleles. Although patient HLA-C*14:02 and donor HLA-C*15:02 mismatch was usually KIR2DL-ligand mismatch in the graft-versus-host direction, the risk of patient mismatched HLA-C*14:02 for severe acute graft-versus-host disease was obvious regardless of KIR2DL-ligand matching. The effect of patient and/or donor HLA-B*51:01 on acute graft-versus-host disease was attributed not only to strong linkage disequilibrium of HLA-C*14:02 and -B*51:01, but also to the effect of HLA-B*51:01 itself. With regard to clinical implications, patient mismatched HLA-C*14:02 proved to be a potent risk factor for severe acute graft-versus-host disease and mortality, and should be considered a non-permissive HLA-C mismatch in donor selection for unrelated donor hematopoietic stem cell transplantation.     

Outcomes after related and unrelated umbilical cord blood transplantation for hereditary bone marrow failure syndromes other than Fanconi anemia

Background

Allogeneic stem cell transplantation is the only curative option for patients with hereditary bone marrow failure syndromes. Umbilical cord blood is an alternative source of stem cells for allogeneic transplantation.

Design and Methods

This multicenter, retrospective study is based on data reported to the Eurocord Registry about patients with hereditary bone marrow failure syndrome who underwent umbilical cord blood transplantation.

Results

Sixty-four patients with hereditary bone marrow failure syndromes were transplanted from related (n=20) or unrelated donors (n=44). Diagnoses were Diamond-Blackfan anemia (21 patients), congenital amegakaryocytic thrombocytopenia (16 patients), dyskeratosis congenita (8 patients), Shwachman-Diamond syndrome (2 patients), severe congenital neutropenia (16 patients) and unclassified (1 patient). In the group of patients who received grafts from related donors, all patients but one received an HLA-matched sibling transplant. The median number of total nucleated cells infused was 5×10⁷/kg. The cumulative incidence of neutrophil recovery at 60 days was 95%. Two patients had grade II–IV acute graft-versus-host disease, while the 2-year cumulative incidence of chronic graft-versus-host disease was 11%. The 3-year overall survival rate was 95%. In the group of patients who received grafts from unrelated donors, 86% had HLA-mismatched grafts and three received two umbilical cord blood units. The median number of total nucleated cells infused was 6.1×10⁷/kg. The cumulative incidence of neutrophil recovery at day 60 in this group was 55%. The 100-day cumulative incidence of grade II–IV acute graft-versus-host disease was 24%, while the 2-year cumulative incidence of chronic graft-versus-host disease was 53%. The 3-year overall survival rate was 61%; better overall survival was associated with age less than 5 years (P=0.01) and 6.1×10⁷/kg or more total nucleated cells infused (P=0.05).

Conclusions

In patients with hereditary bone marrow failure syndromes, related umbilical cord blood transplantation is associated with excellent outcomes while increasing cell dose and better HLA matching might provide better results in unrelated umbilical cord blood transplantation.     

The combination of sirolimus plus tacrolimus improves outcome after reduced-intensity conditioning,unrelated donor hematopoietic stem cell transplantation compared with cyclosporine plus mycofenolate

Different types of graft-versus-host disease prophylaxis have been proposed in the setting of reduced intensity and non-myeloablative allogeneic stem cell transplantation. An alternative combination with sirolimus and tacrolimus has recently been tested although comparative studies against the classical combination of a calcineurin inhibitor and mycophenolate mofetil or methotrexate are lacking. We describe the results of a prospective, multicenter trial using sirolimus + tacrolimus as immunoprophylaxis, and compare this approach with our previous experience using cyclosporine + mycophenolate in the setting of unrelated donor transplantation setting after reduced-intensity conditioning. Forty-five patients received cyclosporine + mycophenolate between 2002 and mid-2007, while the subsequent 50 patients, who were transplanted from late 2007, were given sirolimus + tacrolimus. No significant differences were observed in terms of hematopoietic recovery or acute graft-versus-host disease overall, although gastrointestinal acute graft-versus-host disease grade ≥2 was more common in the cyclosporine + mycophenolate group (55% versus 21%, respectively, P=0.003). The 1-year cumulative incidence of chronic graft-versus-host disease was 50% versus 90% for the patients treated with the sirolimus- versus cyclosporine-based regimen, respectively (P<0.001), while the incidence of extensive chronic disease was 27% versus 49%, respectively (P=0.043). The 2-year non-relapse mortality rate was 18% versus 38% for patients receiving the sirolimus- versus the cyclosporine-based regimen, respectively (P=0.02). The event-free survival and overall survival at 2 years were 53% versus 29% (P=0.028) and 70% versus 45% (P=0.018) among patients receiving the sirolimus- versus the cyclosporine-based regimen, respectively. In conclusion, in the setting of reduced intensity transplantation from an unrelated donor, promising results can be achieved with the combination of sirolimus + tacrolimus, due to a lower risk of chronic graft-versus-host disease and non-relapse mortality, which translates into better event-free and overall survival rates, in comparison with those achieved with cyclosporine + mycophenolate. This trial was registered at www.clinicaltrials.gov as 2007-006416-32 by GEL-TAMO/GETH.     

Risks and benefits of sex-mismatched hematopoietic cell transplantation differ according to conditioning strategy

Sex-mismatched hematopoietic cell transplantation is linked to increased graft-versus-host disease and mortality in myeloablative conditioning. Here we evaluated outcomes of 1,041 adult transplant recipients at two centers between 2006 and 2013 and investigated how the effect of sex-mismatching differed in myeloablative, reduced-intensity, and non-myeloablative total lymphoid irradiation with anti-thymocyte globulin conditioning. Among patients who underwent myeloablative conditioning, male recipients with female donors had increased chronic graft-versus-host disease (hazard ratio 1.83, P<0.01), increased non-relapse mortality (hazard ratio 1.84, P=0.022) and inferior overall survival (hazard ratio 1.59, P=0.018). In contrast, among patients who received reduced-intensity conditioning, male recipients with female donors had increased acute graft-versus-host disease (hazard ratio 1.96, P<0.01) but no difference in non-relapse mortality or overall survival. Among the patients who underwent total lymphoid irradiation with anti-thymocyte globulin, male recipients with female donors showed no increase in graft-versus-host disease or non-relapse mortality. Notably, only in the cohort receiving total lymphoid irradiation with anti-thymocyte globulin were male recipients with female donors significantly associated with reduced relapse (hazard ratio 0.64, P<0.01), and allo-antibody responses against H-Y antigens were predictive of reduced relapse. In the cohort given total lymphoid irradiation with anti-thymocyte globulin, the graft-versus-leukemia effect resulted in superior overall survival in recipients of sex-mismatched grafts (HR 0.69, P=0.037). In addition, only in the cohort treated with total lymphoid irradiation with anti-thymocyte globulin were female recipients with male donors associated with reduced relapse (hazard ratio 0.59, P<0.01) and superior survival (hazard ratio 0.61, P=0.014) compared with sex-matched pairs. We conclude that the risks and benefits of sex-mismatched transplants appear to differ according to conditioning strategy and this could affect donor selection.     

The global severity of chronic graft-versus-host disease, determined by National Institutes of Health consensus criteria, is associated with overall survival and non-relapse mortality

Background

The 2005 National Institutes of Health Consensus Development Conference on chronic graft-versus-host disease proposed major changes in the classification and grading of severity of chronic graft-versus-host disease.

Design and Methods

We aimed to study the association of the proposed chronic graft-versus-host disease classification and global severity with transplantation outcomes among a consecutive series of patients who received pharmacokinetically-targeted doses of intravenous busulfan and fludarabine conditioning followed by transplantation of allogeneic peripheral blood stem cells.

Results

From a total cohort (n = 242) of patients surviving more than 100 days after hematopoietic stem cell transplantation, 181 (75% of those at risk) had some manifestations of graft-versus-host disease after day 100. Of these, at onset 13 (7%) had late acute graft-versus-host disease, 62 (34%) had classic chronic graft-versus-host disease, and 106 (59%) had the overlap subtype of chronic graft-versus-host disease. The global severity of the chronic graft-versus-host disease was mild in 25% of cases, moderate in 46%, and severe in 29%. Multivariable modeling demonstrated the independent association of global severity of chronic graft-versus-host disease with overall survival (moderate/severe versus mild; HR 2.9, 95% CI 1.8–4.7, P<0.0001) and non-relapse mortality (moderate versus mild; HR 3.86, 95% CI 1.17–12.73, P=0.03, and severe versus mild (HR 10.06, 95% CI 3.07–32.97, P<0.001). The type of onset of progressive chronic graft-versus-host disease and the platelet count at the time of diagnosis of the disease were significantly associated with overall survival. The occurrence and severity of chronic graft-versus-host disease was also significantly associated with primary disease relapse.

Conclusions

Patients with moderate to severe chronic graft-versus-host disease, as determined by National Institutes of Health Consensus criteria, have an inferior overall survival and worse non-relapse mortality. Clinical and research advances are needed to improve the outcomes of affected patients.     

Recipient and donor cells in the graft-versus-solid tumor effect: It takes two to tango

Allogeneic hematopoietic stem cell transplantation (alloHSCT) produces –similar to the long-established graft-versus-leukemia effect– graft-versus-solid-tumor effects. Clinical trials reported response rates of up to 53%, occurring mostly but not invariably in association with full donor chimerism and/or graft-versus-host disease. Although donor-derived T cells are considered the principal effectors of anti-tumor immunity after alloHSCT or donor leukocyte infusion (DLI), growing evidence indicate that recipient-derived immune cells may also contribute. Whereas the role of recipient-derived antigen-presenting cells in eliciting graft-versus-host reactions and priming donor T cells following DLI is well known, resulting inflammatory responses may also break tolerance of recipient effector cells towards the tumor. Additionally, mouse studies indicated that post-transplant recipient leukocyte infusion produces anti-leukemia and anti-solid-tumor effects that were exclusively mediated by recipient-type effector cells, without graft-versus-host disease. Here, we review current preclinical and clinical evidence on graft-versus-solid-tumor effects and growing evidence on the effector role of recipient-derived immune cells in the anti-tumor effect of alloHSCT.     

High pre-transplant serum nitrate levels predict risk of acute steroid-refractory graft-versus-host disease in the absence of statin therapy

Steroid-refractory graft-versus-host disease is a life-threatening complication after allogeneic stem cell transplantation. Evidence is accumulating that steroid-refractory graft-versus-host disease is associated with endothelial distress. Endothelial cell homeostasis is regulated by nitric oxide, and serum nitrates are derived from nitric oxide synthase activity or dietary sources. In this retrospective study based on 417 patients allografted at our institution we investigated whether quantification of serum nitrates could predict steroid-refractory graft-versus-host disease. Elevated pre-transplant levels of serum nitrates (>26.5 μM) predicted steroid-refractory graft-versus-host disease (P=0.026) and non-relapse mortality (P=0.028), particularly in combination with high pre-transplant angiopoietin-2 levels (P=0.0007 and P=0.021, respectively). Multivariate analyses confirmed serum nitrates as independent predictors of steroid-refractory graft-versus-host disease and non-relapse mortality. Differences in serum nitrate levels did not correlate with serum levels of tumor necrosis factor or C-reactive protein or expression of inducible nitric oxide synthase in blood cells. Patients with high pre-transplant nitrate levels had significantly reduced rates of refractory graft-versus-host disease (P=0.031) when pravastatin was taken. In summary, patients at high risk of developing steroid-refractory graft-versus-host disease could be identified prior to transplantation by serum markers linked to endothelial cell function. Retrospectively, statin medication was associated with a reduced incidence of refractory graft-versus-host disease in this endothelial high-risk cohort.     

Impact of donor-specific anti-HLA antibodies on graft failure and survival after reduced intensity conditioning-unrelated cord blood transplantation: a Eurocord,Société Francophone d’Histocompatibilité et d’Immunogénétique (SFHI) and Société Fran?aise de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) analysis

Graft failure is a major complication after unrelated cord blood transplantation. Presence of HLA-antibodies before cord blood transplantation may impact graft failure. To analyze the effect of anti-HLA antibodies on unrelated cord blood transplantation outcomes, we analyzed 294 unrelated cord blood transplant recipients after reduced intensity conditioning regimen. The majority of the patients (82%) were transplanted for malignancies, 60% with double-unrelated cord blood transplant, 63% were HLA mismatched. Retrospectively, pre-unrelated cord blood transplant serum was tested for HLA-Ab using Luminex™ platform. Results were interpreted as mean fluorescence intensity (MFI) against donor-specific mismatch. Among 62 recipients (23%) who had anti-HLA antibodies before unrelated cord blood transplant, 14 patients had donor specific anti-HLA antibodies (DSA) (7 were donor-specific anti-HLA antibodies for single unrelated cord blood transplant and 7 for double unrelated cord blood transplant). Donor specific anti-HLA antibodies threshold ranged from 1620–17629 of mean fluorescence intensity (MFI). Cumulative incidence of Day-60 neutrophil engraftment was 76%: 44% for recipients with donor specific anti-HLA antibodies and 81% in those without donor specific anti-HLA antibodies (P=0.006). The cumulative incidence of 1-year transplant related mortality was 46% in patients with donor specific anti-HLA antibodies and 32% in those without antibodies (P=0.06). The presence of donor specific anti-HLA antibodies was associated with a trend for decreased survival rate (42% vs. 29%; P=0.07). Donor specific anti-HLA antibody in recipients of unrelated cord blood transplant is associated with graft failure and decreased survival. Patient’s screening for donor specific anti-HLA antibodies before unrelated cord blood transplantation is recommended before choosing an HLA mismatched cord blood unit. Whenever possible it is important to avoid selecting a unit for which the patient has donor specific anti-HLA antibodies.     

Outcome of aplastic anemia in adolescence: a survey of the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation

We analyzed the outcome of 537 adolescents (age 12–18 years) with idiopathic aplastic anemia included in the database of the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation comparing: i) matched family donor hematopoietic stem cell transplantation performed as first-line treatment with ii) front-line immunosuppressive therapy not followed by subsequent transplant given for failure and with iii) hematopoietic stem cell transplantation performed after failed front-line immunosuppressive therapy. Overall survival was 86% in the matched family donor hematopoietic stem cell transplantation group, 90% in patients given front-line immunosuppressive alone (those who did not fail this treatment and who did not receive subsequent rescue with hematopoietic stem cell transplantation) and 78% in subjects who underwent hematopoietic stem cell transplantation post failed front-line immunosuppressive therapy (P=0.14). Event-free survival in the same groups was respectively 83%, 64% and 71% (P=0.04). Cumulative incidence of rejection was 8% in matched family donor hematopoietic stem cell transplantation and 9% in transplants post failed front-line immunosuppression (P=0.62). Cumulative incidence of acute graft-versus-host disease was 12% in matched family donor transplants and 18% in transplants post failed immunosuppression (P=0.18). Chronic graft-versus-host disease was higher in matched family donor hematopoietic stem cell transplantation (8%) than in transplants post failed immunosuppressive therapy (20%) (P=0.0009). Cumulative incidence of post-therapy malignancies was 0.7% in matched family donor transplantations, 7% in transplantations post failed immunosuppression and 21% after front-line immunosuppression (P=0.0017). In the whole cohort, under multivariate analysis, the diagnosis to treatment interval of two months or under positively affected overall survival whereas up-front immunosuppression alone (with no subsequent rescue transplants) negatively affected event-free survival. In transplanted patients an interval from diagnosis to treatment of 2 months or under, bone marrow as source of cells and first-line matched family donor transplants provided a significant advantage in overall and event-free survival. Aplastic anemia in adolescents has a very good outcome. If a matched family donor is available, hematopoietic stem cell transplantation using bone marrow cells is the first choice treatment. If such a donor is not available, immunosuppressive treatment may still be an acceptable second choice, also because, in case of failure, hematopoietic stem cell transplantation is a very good rescue option.     

Impact of hematopoietic chimerism at day +14 on engraftment after unrelated donor umbilical cord blood transplantation for hematologic malignancies

Background

Cord blood transplant is a feasible treatment alternative for adult patients with hematologic malignancies lacking a suitable HLA-matched donor. However, the kinetics of myeloid recovery is slow, and primary graft failure cannot be detected easily early after transplantation. We investigated the impact of hematopoietic chimerism status from unselected marrow cells 14 days after transplantation on predicting engraftment after a cord blood transplant.

Design and Methods

Seventy-one adult patients with hematologic malignancies undergoing single-unit unrelated donor cord blood transplantation after a myeloablative conditioning regimen were included in the study. All patients received conditioning regimens based on busulfan, thiotepa and antithymocyte globulin. Chimerism status was assessed analyzing short tandem repeat polymorphisms.

Results

The cumulative incidence of myeloid engraftment at 1 month was significantly lower in patients with mixed chimerism than in those with complete donor chimerism (55% vs. 94%; p<0.0001). For patients achieving myeloid recovery, the median time of engraftment was 16 days when donor chimerism at day + 14 was higher than 90%, compared with 24 days when donor chimerism was below this level (p<0.001). A donor chimerism level of 65% was found to be the best cut-off point for predicting primary graft failure, with a sensitivity of 97% and a specificity of 80%. The incidence of primary graft failure was 67% for patients with less than 65% donor chimerism at day +14 as compared to only 2% for those with more than 65% donor chimerism (p<0.001). Patients with mixed chimerism also had a lower cumulative incidence of platelet engraftment than those with complete chimerism (62% vs. 89%; p=0.01).

Conclusions

Donor-recipient chimerism status at day +14 predicts engraftment after a single-unit cord blood transplant in adults.     

Refined HLA-DPB1 mismatch with molecular algorithms predicts outcomes in hematopoietic stem cell transplantation

HLA-DPB1 mismatches between donor and recipient are commonly seen in allogeneic hematopoietic stem cell transplantation from an unrelated donor. HLA-DPB1 mismatch, conventionally determined by the similarity of the T-cell epitope (TCE), is associated with an increased risk of acute graft-versus-host disease (GVHD) and a decreased risk of disease relapse. We investigated the clinical impact of HLA-DPB1 molecular mismatch quantified by mismatched eplets (ME) and the Predicted Indirectly Recognizable HLA Epitopes Score (PS) in a cohort of 1,514 patients receiving hematopoietic stem cell transplants from unrelated donors matched at HLA-A, -B, -C, -DRB1/3/4/5, and - DQB1 loci. HLA-DPB1 alloimmunity in the graft-versus-host direction, determined by high graft-versus-host ME/PS, was associated with a reduced risk of relapse (hazard ratio [HR]=0.83, P=0.05 for ME) and increased risk of grade 2-4 acute GVHD (HR=1.44, P<0.001 for ME), whereas high host-versus-graft ME/PS was only associated with an increased risk of grade 2-4 acute GVHD (HR=1.26, P=0.004 for ME). Notably, in the permissive mismatch subgroup classified by TCE grouping, high host-versus-graft ME/PS was associated with an increased risk of relapse (HR=1.36, P=0.026 for ME) and grade 2-4 acute GVHD (HR=1.43, P=0.003 for PS-II). Decision curve analysis showed that graftversus- host ME outperformed other models and provided the best clinical net benefit for the modification of acute GVHD prophylaxis regimens in patients with a high risk of developing clinically significant acute GVHD. In conclusion, molecular assessment of HLA-DPB1 mismatch enables separate prediction of host-versus-graft or graft-versus-host alloresponse quantitatively and allows further refinement of HLA-DPB1 permissiveness as defined by conventional TCE grouping.     

Current outcome of HLA identical sibling versus unrelated donor transplants in severe aplastic anemia: an EBMT analysis

We have analyzed 1448 patients with acquired aplastic anemia grafted between 2005 and 2009, and compared outcome of identical sibling (n=940) versus unrelated donor (n=508) transplants. When compared to the latter, sibling transplants were less likely to be performed beyond 180 days from diagnosis (39% vs. 85%), to have a cytomegalovirus negative donor/recipient status (15% vs. 23%), to receive antithymocyte globulin in the conditioning (52% vs. 61%), and more frequently received marrow as a stem cell source (60% vs. 52%). Unrelated donor grafts had significantly more acute grade II–IV (25% vs. 13%) and significantly more chronic graft-versus-host disease (26% vs. 14%). In multivariate analysis, the risk of death of unrelated donor grafts was higher, but not significantly higher, compared to a sibling donor (P=0.16). The strongest negative predictor of survival was the use of peripheral blood as a stem cell source (P<0.00001), followed by an interval of diagnosis to transplant of 180 days or more (P=0.0005), patient age 20 years or over (P=0.0005), no antithymocyte globulin in the conditioning (P=0.003), and donor/recipient cytomegalovirus sero-status, other than negative/negative (P=0.04). In conclusion, in multivariate analysis, the outcome of unrelated donor transplants for acquired aplastic anemia, is currently not statistically inferior when compared to sibling transplants, although patients are at greater risk of acute and chronic graft-versus-host disease. The use of peripheral blood grafts remains the strongest negative predictor of survival.     

Use of the HLA-B leader to optimize cord blood transplantation

Cord blood transplantation (CBT) can cure life-threatening blood disorders. The HLA-B leader affects the success of unrelated donor transplantation but its role in CBT is unknown. We tested the hypothesis that the HLA-B leader influences CBT outcomes in unrelated single-unit cord blood transplants performed by Eurocord/European Blood and Marrow Transplant (EBMT) centers between 1990 and 2018 with data reported to Eurocord. Among 4,822 transplants, 2,178 had one HLA-B mismatch of which 1,013 were HLAA and HLA-A and -DRB1 matched. The leader (methionine [M] or threonine [T]) was determined for each HLA-B allele in patients and units to define the genotype. Among single HLA-B-mismatched transplants, the patient/unit mismatched alleles were defined as leader-matched if they encoded the same leader, or leader-mismatched if they encoded different leaders; the leader encoded by the matched (shared) allele was determined. The risks of graft-versus-host disease, relapse, non-relapse mortality and overall mortality were estimated for various leader-defined groups using multi-variable regression models. Among the 1,013 HLA-A and -DRB1-matched transplants with one HLA-B mismatch, increasing numbers of cord blood unit M-leader alleles was associated with increased risk of relapse (hazard ratio [HR] for each increase in one Mleader allele 1.30, 95% Confidence Interval [CI]: 1.05-1.60, P=0.02). Furthermore, leader mismatching together with an M-leader of the shared HLA-B allele lowered non-relapse mortality (HR 0.44, 95% CI: 0.23-0.81; P=0.009) relative to leader matching and a shared T-leader allele. The HLA-B leader may inform relapse and non-relapse mortality risk after CBT. Future patients might benefit from the appropriate selection of units that consider the leader.     

Unrelated umbilical cord blood transplant for adult acute lymphoblastic leukemia in first and second complete remission: a comparison with allografts from adult unrelated donors

Allogeneic hematopoietic cell transplantation has an established role in the treatment of adults with acute lymphoblastic leukemia whose survival when recipients of grafts from adult unrelated donors approaches that of recipients of grafts from sibling donors. Our aim was to determine the role of mismatched unrelated cord blood grafts in transplantation for 802 adults with acute lymphoblastic leukemia in first or second complete remission. Using Cox regression we compared outcomes after 116 mismatched single or double cord blood transplants, 546 peripheral blood progenitor cell transplants and 140 bone marrow transplants. The characteristics of the recipients and their diseases were similar except cord blood recipients were younger, more likely to be non-Caucasians and more likely to have a low white blood cell count at diagnosis. There were differences in donor-recipient human leukocyte antigen-match depending on the source of the graft. Most adult donor transplants were matched at the allele-level considering human leukocyte antigens-A, -B, -C and –DRB1. In contrast, most cord blood transplants were mismatched and considered antigen-level matching; 57% were mismatched at two loci and 29% at one locus whereas only 29% of adult donor transplants were mismatched at one locus and none at two loci. There were no differences in the 3-year probabilities of survival between recipients of cord blood (44%), matched adult donor (44%) and mismatched adult donor (43%) transplants. Cord blood transplants engrafted slower and were associated with less grade 2–4 acute but similar chronic graft-versus-host disease, relapse, and transplant-related mortality. The survival of cord blood graft recipients was similar to that of recipients of matched or mismatched unrelated adult donor grafts and so cord blood should be considered a valid alternative source of stem cells for adults with acute lymphoblastic leukemia in the absence of a matched unrelated adult donor.     

A Good Manufacturing Practice procedure to engineer donor virus-specific T cells into potent anti-leukemic effector cells

A sequential, two-step procedure in which T-cell-depleted allogeneic stem cell transplantation is followed by treatment with donor lymphocyte infusion at 6 months can significantly reduce the risk and severity of graft-versus-host disease, with postponed induction of the beneficial graft-versus-leukemia effect. However, patients with high-risk leukemia have a substantial risk of relapse early after transplantation, at a time when administration of donor lymphocytes has a high likelihood of resulting in graft-versus-host disease, disturbing a favorable balance between the graft-versus-leukemia effect and graft-versus-host disease. New therapeutic modalities are, therefore, required to allow early administration of T cells capable of exerting a graft-versus-leukemia effect without causing graft-versus-host disease. Here we describe the isolation of virus-specific T cells using Streptamer-based isolation technology and subsequent transfer of the minor histocompatibility antigen HA-1-specific T-cell receptor using retroviral vectors. Isolation of virus-specific T cells and subsequent transduction with HA-1-T-cell receptor resulted in rapid in vitro generation of highly pure, dual-specific T cells with potent anti-leukemic reactivity. Due to the short production procedure of only 10–14 days and the defined specificity of the T cells, administration of virus-specific T cells transduced with the HA-1-T-cell receptor as early as 8 weeks after allogeneic stem cell transplantation is feasible. (This clinical trial is registered at www.clinicaltrialsregister.eu as EudraCT number 2010-024625-20).     

Bone marrow versus peripheral blood as the stem cell source for sibling transplants in acquired aplastic anemia: survival advantage for bone marrow in all age groups

Background

Bone marrow has been shown to be superior to peripheral blood, as a stem cell source, in young patients (<20 years of age) with acquired aplastic anemia undergoing a matched sibling transplant. The aim of this study was to test whether this currently also holds true for older patients with acquired aplastic anemia.

Design and Methods

We analyzed 1886 patients with acquired aplastic anemia who received a first transplant from a human leukocyte antigen identical sibling between 1999 and 2009, with either bone marrow (n=1163) or peripheral blood (n=723) as the source of stem cells.

Results

In multivariate Cox analysis negative predictors for survival were: patient’s age over 20 years (RR 2.0, P<0.0001), an interval between diagnosis and transplantation of more than 114 days (RR 1.3, P=0.006), no anti-thymocyte globulin in the conditioning (RR 1.6, P=0.0001), a conditioning regimen other than cyclophosphamide (RR=1.3, P=0.008) and the use of peripheral blood as the source of stem cells (RR 1.6, P<0.00001). The survival advantage for recipients of bone marrow rather than peripheral blood was statistically significant in patients aged 1–19 years (90% versus 76% P<0.00001) as well as in patients aged over 20 years (74% versus 64%, P=0.001). The advantage for recipients of bone marrow over peripheral blood was maintained above the age of 50 years (69% versus 39%, P=0.01). Acute and chronic graft-versus-host disease were more frequent in peripheral blood transplants. Major causes of death were graft-versus-host disease (2% versus 6% in bone marrow and peripheral blood recipients, respectively), infections (6% versus 13%), and graft rejection (1.5% versus 2.5%).

Conclusions

This study shows that bone marrow should be the preferred stem cell source for matched sibling transplants in acquired aplastic anemia, in patients of all age groups.     

Mesenchymal stromal cells transiently alter the inflammatory milieu post-transplant to delay graft-versus-host disease

Background

Multipotent mesenchymal stromal cells suppress T-cell function in vitro, a property that has underpinned their use in treating clinical steroid-refractory graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. However the potential of mesenchymal stromal cells to resolve graft-versus-host disease is confounded by a paucity of pre-clinical data delineating their immunomodulatory effects in vivo.

Design and Methods

We examined the influence of timing and dose of donor-derived mesenchymal stromal cells on the kinetics of graft-versus-host disease in two murine models of graft-versus-host disease (major histocompatibility complex-mismatched: UBI-GFP/BL6 [H-2^b]→BALB/c [H-2^d] and the sibling transplant mimic, UBI-GFP/BL6 [H-2^b]→BALB.B [H-2^b]) using clinically relevant conditioning regimens. We also examined the effect of mesenchymal stromal cell infusion on bone marrow and spleen cellular composition and cytokine secretion in transplant recipients.

Results

Despite T-cell suppression in vitro, mesenchymal stromal cells delayed but did not prevent graft-versus-host disease in the major histocompatibility complex-mismatched model. In the sibling transplant model, however, 30% of mesenchymal stromal cell-treated mice did not develop graft-versus-host disease. The timing of administration and dose of the mesenchymal stromal cells influenced their effectiveness in attenuating graft-versus-host disease, such that a low dose of mesenchymal stromal cells administered early was more effective than a high dose of mesenchymal stromal cells given late. Compared to control-treated mice, mesenchymal stromal cell-treated mice had significant reductions in serum and splenic interferon-γ, an important mediator of graft-versus-host disease.

Conclusions

Mesenchymal stromal cells appear to delay death from graft-versus-host disease by transiently altering the inflammatory milieu and reducing levels of interferon-γ. Our data suggest that both the timing of infusion and the dose of mesenchymal stromal cells likely influence these cells’ effectiveness in attenuating graft-versus-host disease.     

Sensitivity of changes in chronic graft-versus-host disease activity to changes in patient-reported quality of life: results from the Chronic Graft-versus-Host Disease Consortium

Background

The 2005 National Institute of Health Chronic Graft-versus-Host Disease Consensus Conference recommended collection of patient-reported outcomes in clinical trials on chronic graft-versus-host disease. We assessed whether changes in chronic graft-versus-host disease severity, determined using National Institute of Health criteria, clinicians’ assessment or patients’ self-evaluation, correlated with patient-reported quality of life as measured by the Short Form-36 and Functional Assessment of Cancer Therapy – Bone Marrow Transplant (FACT-BMT) instruments.

Design and Methods

Three-hundred and thirty-six adult patients (median age 52 years; range, 19 – 79) with chronic graft-versus-host disease from six transplant centers contributed baseline and follow-up data (from 936 visits overall).

Results

While the majority of the patients had stable chronic graft-versus-host disease, improvement or worsening was noted in approximately 40% of follow-up visits. Multivariable analysis demonstrated no association between change in chronic graft-versus-host disease severity evaluated by National Institute of Health criteria and change in quality of life, while clinician-reported changes in severity were associated with changes in some quality of life measures. Patient-reported changes in the severity of chronic graft-versus-host disease were associated with changes in all quality of life measures. Comparison of the Short Form-36 and the FACT-BMT suggested that the data collected in the Functional Assessment of Cancer Therapy – General (FACT-G) core survey are sufficient without the need for the Short Form-36 or the FACT–BMT subscale.

Conclusions

We conclude that serial National Institute of Health and clinician-reported chronic graft-versus-host disease severity assessments cannot substitute for patient-reported outcomes in clinical trials. Collection of just the FACT-G instead of the Short Form-36 and the full FACT-BMT will decrease respondent burden without compromising quality of life assessment.