Unrelated Donor Hematopoietic Stem Cell Research Articles

Risk factors and outcome of graft failure after HLA matched and mismatched unrelated donor hematopoietic stem cell transplantation: a study on behalf of SFGM-TC and SFHI

Graft failure remains a severe complication of hematopoietic stem cell transplantation (HSCT). Several risk factors have already been published. In this study, we re-evaluated them in a large cohort who had the benefit of the recent experience in HSCT (2006-2012). Data from 4684 unrelated donor HSCT from 2006 to 2012 were retrospectively collected from centers belonging to the French Society for Stem Cell Transplantation. Among the 2716 patients for whom HLA typing was available, 103 did not engraft leading to a low rate of no engraftment at 3.8%. In univariate analysis, only type of disease and status of disease at transplant for malignant diseases remained significant risk factors (P=0.04 and P<0.0001, respectively). In multivariate analysis, only status of disease was a significant risk factor (P<0.0001). Among the 61 patients who did not engraft and who were mismatched for 1 HLA class I and/or HLA-DP, 5 donor-specific antibodies (DSAs) were detected but only 1 was clearly involved in graft failure, for the others their role was more questionable. Second HSCT exhibited a protective although not statistically significant effect on OS (hazard ratio=0.57 [0.32-1.02]). In conclusion, only one parameter (disease status before graft) remains risk factor for graft failure in this recent cohort.

Evolving hematopoietic stem cell transplantation strategies in severe aplastic anemia.

Significant improvements in unrelated donor hematopoietic stem cell transplantation (HSCT) in recent years have solidified its therapeutic role in severe aplastic anemia (SAA) and led to the evolution of treatment algorithms, particularly for children. Advances in understanding the genetics of inherited bone marrow failure syndromes (IBMFS) have allowed more confidence in accurately diagnosing SAA and avoiding treatments that could be dangerous and ineffective in individuals with IBMFS, which can be diagnosed in 10-20% of children presenting with a picture of SAA. Additionally long-term survival after matched sibling donor and matched unrelated donor HSCT now exceed 90% in children. Late effects after HSCT for SAA are minimal with current strategies, and compare favorably to late effects after upfront immunosuppressive therapy, except for patients with chronic graft versus host disease. Careful assessment for signs or symptoms of IBMFS, along with genetic screening for these disorders, is of major importance. Matched sibling donor HSCT is already considered the standard of care for upfront therapy and some groups are evaluating matched unrelated donor HSCT as primary therapy. Ongoing studies will continue to challenge treatment algorithms and may lead to an even more expanded role for HSCT in SAA.

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.

Low Socioeconomic Status, Adverse Gene Expression Profiles, and Clinical Outcomes in Hematopoietic Stem Cell Transplant Recipients.

Low socioeconomic status (SES) is associated with adverse outcomes among unrelated donor hematopoietic stem cell transplant (HCT) recipients, but the biologic mechanisms contributing to this health disparity are poorly understood. Therefore, we examined whether social environment affects expression of a stress-related gene expression profile known as the conserved transcriptional response to adversity (CTRA), which involves upregulation of proinflammatory genes and downregulation of genes involved in type I IFN response and antibody synthesis. We compared pretransplant leukocyte CTRA gene expression between a group of 78 high versus low SES recipients of unrelated donor HCT for acute myelogenous leukemia in first remission. Post hoc exploratory analyses also evaluated whether CTRA gene expression was associated with poor clinical outcomes. Peripheral blood mononuclear cells collected pre-HCT from low SES individuals demonstrated significant CTRA upregulation compared with matched HCT recipients of high SES. Promoter-based bioinformatics implicated distinct patterns of transcription factor activity, including increased CREB signaling and decreased IRF and GR signaling. High expression of the CTRA gene profile was also associated with increased relapse risk and decreased leukemia-free survival. Low SES is associated with increased expression of the CTRA gene profile, and CTRA gene expression is associated with adverse HCT clinical outcomes. These findings provide a biologic framework within which to understand how social environmental conditions may influence immune function and clinical outcomes in allogeneic HCT.

Highlights of This Issue

Low socioeconomic status (SES) is associated with adverse outcomes among unrelated donor hematopoietic stem cell transplant (HCT) recipients, but the biological mechanisms contributing to this health disparity are poorly understood. Knight and colleagues found that low-SES HCT recipients show up-regulation of a conserved transcriptional response to adversity (CTRA) gene expression profile at pretransplant testing. Up-regulated CTRA gene expression was also associated with increased relapse and decreased leukemia-free survival. These results suggest new strategies for mitigating social disparities in cancer treatment outcomes through targeted pharmacologic intervention in the signaling pathways that drive CTRA gene expression.Hatzis and colleagues developed a statistical model to help design the next generation of clinical trials for breast cancer that simultaneously test drug activity in the preoperative (neoadjuvant) treatment setting and the impact on patient survival. Neoadjuvant chemotherapy often completely eradicates the cancer from the breast and lymph nodes, but does not always result in improved survival. The team found higher expected survival benefit for cancers with high risk of recurrence when treated with more effective novel therapies, highlighting the importance of assessing novel treatments in patients that have high risk for recurrence despite current best therapies.Combinations of ibrutinib with anti-CD20 monoclonal antibodies (mAbs) are being evaluated in clinical trials; however, in vitro data identified potentially negative interactions between the two drugs. Skarzynski and colleagues provide conclusive evidence that ibrutinib leads to CD20 downregulation on chronic lymphocytic leukemia (CLL) cells in vivo, resulting in decreased complement-dependent cytotoxicity. Yet, concurrent CD55 (complement inhibitor) downregulation and partial inhibition of mAb-mediated shaving of CD20 from CLL cells by effector cells (trogocytosis) could enhance mAb activity. These positive and negative interactions between ibrutinib and anti-CD20 mAbs could determine the overall therapeutic efficacy of combination therapy and should be investigated further.The site of recurrence affects prognosis in metastatic breast cancer, but the events underlying organ-specificity of metastases are elusive. The authors explored the global transcriptional landscape of clinical breast cancer metastases, unraveling a liver metastasis-selective signature enriched for stromal genes that were predominantly downregulated in liver metastases. Downregulation of the signature was predictive of poor outcome in early breast cancer, with the strongest independent prognostic value within the luminal A subtype. This signature identifies patients with ER-positive breast cancer requiring closer disease monitoring who may be amenable to enrolment into clinical trials investigating novel therapeutics targeting features other than proliferation.

Post-Transplantation High Dose Cyclophosphamide As Gvhd Prophylaxis in 9/10 HLA-Matched Unrelated Donors Hematopoietic Stem Cell Transplantation

Background: Post-transplantation cyclophosphamide (PTCy) is an effective strategy to prevent GVHD after haploidentical or HLA-matched related or unrelated donor hematopoietic stem cell transplantation (HSCT). Our study aim was to determine its efficacy in HLA-mismatched unrelated donor (MMUD) HSCT.Methods: We included 113 consecutive adult patients with high risk hematological malignancies who underwent one-antigen MMUD (9/10-matched) bone marrow (BM) or peripheral blood (PB) HSCT after myeloablative or reduced-intensity conditioning at our institution from 2009-2013. Outcomes were compared between (a) conventional GVHD group (n=71) that received in-vivo T-cell depletion with ATG, tacrolimus and methotrexate and (b) PTCy group (n=41) that received PTCy (50 mg/kg/day IV on days 3 and 4) with tacrolimus and MMF. After exclusion of 29 patients with isolated HLA-DQ mismatches, a separate analysis was performed in 84 patients with 7/8 HLA-MUD HSCT; 38 patients received PTCy while 46 patients received conventional prophylaxis.Results: Patients in the conventional group were marginally older (median 54 years; range 19-74) than those in the PTCy group (median 50 years; range 20-64). PB was used more frequently as a graft source in the conventional group (38% vs 17%, p=0.02). PTCy group included more patients with HLA class-I mismatches (87.8%) compared to conventional group (56.9%). There were no other differences between the groups.Incidence of grade II-IV (37% vs 36%, p=0.8) or grade III-IV (17% vs 12%, p=0.5) acute GVHD at day 100 post-transplant was not different between the groups. [Figure 1] Incidence of grade II-IV acute GVHD at day 30 was significantly lower after PTCy compared with conventional prophylaxis (0% vs 15%, p <0.001). Correspondingly, incidence of grade III-IV GVHD at day 30 was 0% in the PTCy group and 8% in the conventional group (p=0.08). Cumulative incidence of chronic GVHD was similar between the two groups at 6 months (20% vs 15%), 1-year (30% vs 31%) or 2-years (30% vs 42%). Risk factors analysis showed that use of PTCy was the sole independent predictor of lower risk of grade II-IV acute GVHD at day 30 (p=0.01). None of the risk factors evaluated, including PTCy use, were shown to predict the rate of grade II-IV acute GVHD within day 100. Two-year cumulative incidences of NRM (35% vs 25%), disease progression (20% vs 31%), DFS (42% vs 38%) and OS (52% vs 40%) were similar in the PTCy and the conventional groups, respectively. [Figure 1] Median times to neutrophil (18 vs. 12 days, p<0.001) and platelet (25.5 vs. 18 days, p=0.05) engraftment were prolonged in PTCy group. Disease recurrence/persistence was the leading cause of death in both groups, accounting for about 46% of all deaths. Subgroup analysis restricting to patients with BM grafts produced similar findings.In patients with HLA class-I mismatch, PTCy was associated with significantly reduced risk of grade II-IV, but not grade III-IV, acute GVHD at day 30 (p=0.01). However, there were no differences in acute grade II-IV GVHD (HR 1.1, 95% C.I. 0.5-2.5, p=0.7) or acute grade III-IV GVHD (HR 1.5, 95% C.I. 0.4-5.4, p=0.5) by day 100 between the groups.Comparing patients with 7/8-HLA-MUD HSCT, no patient in PTCy group developed acute GVHD at day 30 compared with 8 patients in conventional group (p=0.005). There were no differences in incidence of grade II-IV (HR 1, 95% C.I. 0.5-2.1, p=0.9) or grade III-IV (HR 1.1, 95% C.I. 0.3-3.3, p=0.9) acute GVHD at day 100, chronic GVHD at 6 months (HR 0.8, 95% C.I. 0.2-2.9, p=0.7), 1-year (HR 0.8, 95% C.I. 0.3-2.2, p=0.6) or 2-years (HR 0.7, 95% C.I. 0.2-1.9, p=0.5) between the groups.Conclusion: Our results demonstrate that PTCy, tacrolimus and MMF for GVHD prophylaxis is safe and produced similar results as conventional prophylaxis in patients with one antigen HLA-MMUD HSCT. [Display omitted] DisclosuresAlousi:Therakos, Inc: Research Funding.

Evaluation of the Impact of Non-Inherited Maternal Antigens on the Outcome of HLA Mismatched Unrelated Donor Hematopoietic Stem Cell Transplantation for Hematological Malignancies on Behalf of the ALWP of the EBMT and the CIBMTR

Allogeneic hematopoietic stem cell transplantation (HSCT) offers a potential cure for a variety of hematological malignancies. Patients without an HLA matched sibling donor can turn to unrelated donor registries to identify a suitably HLA matched donor. In the case where a fully HLA-A, -B, -C, -DRB1 and -DQB1 (10/10) matched donor is unavailable, there are often multiple 9/10 matched donors to select from. However, the prioritization and identification of permissive HLA mismatches in the 9/10 matched setting have proven elusive. Fetal exposure to non-inherited maternal antigens (NIMA) imparts lifelong immune modulating effects leading to tolerance to these antigens. Prior studies have found that matching for non-inherited maternal antigens (NIMA) can lead to lower rates of acute graft versus host disease (aGVHD) and lower treatment-related mortality (TRM) in cord blood HSCT (J.J. van Rood et al., Blood 2002; J. J. van Rood et al., PNAS, 2009; V. Rocha et al., BBMT, 2012). Patients undergoing mismatched HSCT with adult unrelated donors could benefit from NIMA matching by introducing maternal HLA testing during confirmatory typing of the donor and using NIMA matching as a criterion for mismatched donor selection.This joint EBMT-CIBMTR retrospective analysis was designed to evaluate the influence of NIMA matching in HSCT with mismatched adult unrelated donors. Matching criteria were based on HLA-A, -B, -C, -DRB1, -DQB1 at high resolution. Included donor-recipient pairs had 5 loci HLA typing and a minimum of one year follow-up recorded at EBMT or CIBMTR and donors were registered with DKMS German Bone Marrow Donor Center. To obtain maternal HLA typing information, DKMS contacted the respective donors by mail to inform about the study and to provide detailed information, a buccal swab kit and an informed consent form to the donor's mother that the donor could send on. SBT-based HLA typing was performed at the DKMS Life Science Lab, Dresden, Germany once signed informed consent and samples were received. A total of 1735 donors were contacted and maternal samples could be retrieved for 803 cases (46%). A total of 50 NIMA matches (6%) were found reflecting the rate expected from previous studies.Multivariate analyses were performed using Cox proportional hazards models adjusting for significant co-variates for overall survival (OS), disease free survival (DFS), relapse, TRM and acute and chronic GVHD comparing NIMA matched to NIMA mismatched cases.The final analysis population was restricted to 9/10 matched cases (N=452) transplanted for acute myeloid leukemia (N=307) and acute lymphoblastic leukemia (N=145) using myeloablative (N=307) or reduced intensity (N=145) conditioning from 1999-2013. The NIMA matched (N=32) and mismatched (N=420) groups were well balanced for all disease, patient, transplant and donor characteristics. The groups differed by mismatched HLA locus with the NIMA matched group skewed towards more HLA-C mismatches (66% vs. 35%). Univariate analyses did not find any significant differences between the NIMA matched and mismatched groups for any outcomes. TRM rates were similar between the groups at 1 year with 23% (95% CI: 10-40%) and 23% (95% CI: 19-28%) in the NIMA matched and mismatched groups, respectively. No significant associations were observed in multivariate analyses of the NIMA matched versus mismatched groups (Table).In contrast to prior studies of NIMA matched HSCT, no significant associations were found between NIMA matching and any outcomes. However, our findings may be due to the fact that the current study was underpowered to detect the expected difference in TRM observed in prior studies. Investigation on a larger cohort or a prospective trial would be needed.We thank Carlheinz Müller from the German unrelated donor registry ZKRD for providing additional HLA information and the donors and their mothers for their cooperation in this study.Table. Multivariate analysis results of NIMA matched versus mismatched (used as reference) HSCT Table 1OutcomeHR95% CIp-valueOS0.890.54-1.480.653DFS0.880.53-1.430.598TRM0.740.35-1.600.447Relapse0.890.45-1.750.737aGVHD II-IV0.970.53-1.800.935aGVHD III-IV0.590.19-1.910.382cGVHD1.770.99-3.160.053 DisclosuresLee:Bristol-Myers Squibb: Consultancy; Kadmon: Consultancy. Nagler:Biokine LTD: Consultancy.

Przyczyny dyskwalifikacji niespokrewnionych dawców krwiotwórczych komórek macierzystych

BackgroundIn the recent years the population of registered unrelated hematopoietic stem cell donors in Poland expanded to over 768 000 in 2014. In parallel the number of hematopoietic stem cell donations rose to over 900 in 2014. So far there are very little data about unrelated hematopoietic stem cell donors in Poland. AimsAnalysis of most common deferral reasons of unrelated hematopoietic stem cell donors at the time of final clearance before transplantation. Methods465 medical records of unrelated donors who underwent final clearance were analyzed. The deferral reasons were analyzed and compared with recent World Marrow Donor Association (WMDA) and National Marrow Donor Program (NMDP) guidelines for donor selection. Results1.5% of donors were permanently deferred at the final clearance – mostly with random medical conditions. 8% of donors (n=38) were temporarily deferred at the final clearance. Among them the deferral causes included: suspicion of recent or ongoing Toxoplasmosis (n=17); autoimmune thyroiditis (n=3); ongoing CMV infection (n=2) and other reasons (n=16). The median time of temporal deferral was 6 weeks. Except for the cases with suspicion of Toxoplasmosis, the temporal deferral over 3 weeks results in very low chances of donation (5%, n=19). ConclusionThe percentages of permanent deferrals are low in Polish donors. The temporal deferrals are mostly based on suspicion of infectious diseases. The temporal deferrals of over 3 weeks in most of the cases effectively block the donation possibility.

Unrelated donor hematopoietic stem cell transplantation for the treatment of non-malignant genetic diseases: An alemtuzumab based regimen is associated with cure of clinical disease; earlier clearance of alemtuzumab may be associated with graft rejection.

Hematopoietic stem cell transplantation (HSCT) with matched unrelated donors (MUD), offers potentially curative therapy for patients with non-malignant genetic diseases. In this pilot study conducted from 2006 to 2014, we report the outcomes of 15 patients with non-malignant genetic diseases who received a myeloablative regimen with a reduced cyclophosphamide dose, adjunctive serotherapy and MUD HSCT [intravenous alemtuzumab (52 mg/m(2) ), busulfan (16 mg/kg), fludarabine (140mg/m(2) ), and cyclophosphamide (105 mg/kg)]. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus/cyclosporine and methylprednisolone. Median (range) time to neutrophil engraftment (>500 cells/µL) and platelet engraftment (>20,000/mm(3) ) were 15 (12-28) and 25 (17-30) days, respectively. At a median follow-up of 2 (0.2-5.4) years, the overall survival (OS) was 93.3% (95% CI: 0.61-0.99) and disease-free survival (DFS) was 73.3% (95% CI: 0.44-0.89). Among this small sample, earlier alemtuzumab clearance was significantly associated with graft rejection (P = 0.047), earlier PHA response (P = 0.009) and a trend toward earlier recovery of recent thymic emigrants (RTE) (P = 0.06). This regimen was associated with durable donor engraftment and relatively low rates of regimen related toxicity (RRT); future alemtuzumab pharmacokinetic studies may improve outcomes, by allowing targeted alemtuzumab clearance to reduce graft rejection and promote more rapid immune reconstitution.

Identification of a novel HLA-B*46:01 variant, HLA-B*46:01:20, in a Taiwanese unrelated hematopoietic stem cell donor.

One nucleotide replacement at residue 528 of HLA-B*46:01:01 results in a new allele, HLA-B*46:01:20.

Donor KIR Genotype BX1 had a negative effect while centromeric B-Specific gene motifs had a positive effect of survival for standard risk AML Patients after unrelated donor hemotopoietic stem cell transplantation

Aim To investigate the impact of donor Killer Immunoglobulin-like Receptors (KIR) genotypes and centromeric motif B (Cen-B) on clinical outcomes after unrelated donor (URD) hematopoietic stem cell transplantation (HSCT) for Chinese population. Method A total of 210 Chinese patients underwent URD-HSCT were investigated in this 4-year retrospective study. KIR genotyping and HLA typing were performed for the population. Results The risk of transplant from Bx1 donors and the benefit of the presence of Cen-B (ignoring the number) were observed for standard risk AML/MDS patients Donor KIR genotype Bx was associated with significant improved OS (P = .026) and RFS (P = .021), and reduced NRM (P = .017) for AML/MDS patients. A much worse survival was observed for transplants from Bx1donors compared to Bx2, Bx3, and Bx4 donors for patients in CR1, ( n = 82; OS: P = .024; RFS: P = .021). Transplant form donors with Cen-B improved OS (HR = .256; 95% CI = .084 to .774; P = .016) and RFS (HR = .252; 95% CI = .084 to .758; P = .014) for AML/MDS patients in CR1. However, the effect did not increase with the number of Cen-B motifs (cB/B vs. cA/B; OS: P = .755; RFS: P = .768). No effect was observed for high risk AML/MDS and ALL/NHL, CML patients. Conclusions Avoiding the selection of HSCT donors with KIR genotype Bx1 is strongly advisable for AML/MDS patients of standard risk. The presence of cen-B motif rather than the number was more important in donor selection for Chinese population.

Anti-HLA antibodies detected before and anti-HLA antibodies detected before and after HLA-12/12 matched unrelated donor of allo-HSCT can negatively impact the outcomes, but HLA-DP loci mismatches have no significance

Aim To investigate the impact of patients with anti-HLA antibodies or with donors mismatched at HLA-DP locus on outcomes after unrelated-donor hematopoietic stem cell transplantation (HSCT). Method We explored the data from 123 patients that received allo-HSCT matched for HLA-A, B, C, DRB1, DQB1, and DQA1 (12/12) from unrelated donors from the CMDP with a 2-year follow up. The examination of anti-HLA antibodies was scheduled at 3 time points: before the start of conditioning treatment and 1 month, 3 months after transplantation. Results The presence of anti-HLA antibodies detected before and 1 month, 3 months after transplantation was 37.4% (46/123), 40.2% (47/117), 22.6% (24/106), respectively. 16.4% (18/110) recipients with donors matched in HLA-DPA1 and HLA -DPB1 loci, and the mismatched rate was 83.6% (92/110). Patients with preformed anti-HLA antibodies had delayed platelet recovery. Anti-HLA antibodies detected before and after transplantation were responsible for increased occurrence of grade 2–4 acute graft-versus host disease (aGVHD) and reduced overall survival (OS), especially in acute myeloid leukemia and myelodysplastic syndrome patients. Pre-existing HLA-Ab was an independent risk factor for the GVHD and OS. Unfortunately, we found that HLA-DP mismatches have nothing to do with outcomes after transplantation. For HLA-Ab negative group, HLA-DP matched subgroup had a modest trend towards a lower rate of aGVHD, and a higher occurrence of OS and DFS compared with HLA-DP mismatched subgroup. Conclusions Our results suggest that anti-HLA antibodies detected before and after transplantation had a negative effect of outcomes, but HLA-DP loci mismatches have no significance after HLA- 12/12 matched unrelated donor of allo-HSCT. Anti-HLA antibodies should be the primary consideration in the setting of HLA 12/12-matched unrelated-donor HSCT, followed by the status of HLA-DP matching.

A novel HLA allele, HLA-DRB1*13:204, detected in a Brazilian unrelated hematopoietic stem cell donor.

The HLA-DRB1*13:204 allele differs from HLA*13:64 by two nucleotide substitutions at positions 181 and 189 in the exon 2.

Suitability Criteria for Adult Related Donors: A Consensus Statement from the Worldwide Network for Blood and Marrow Transplantation Standing Committee on Donor Issues.

The number of allogeneic hematopoietic stem cell (HSC) transplants performed globally each year continues to increase. Advances in HLA typing, better supportive care, and administration of reduced-intensity conditioning regimens allow treatment of older patients with older sibling donors. Pretransplant donor assessment and testing are very important processes affecting the quality and safety of donation. For unrelated HSC donors detailed recommendations for health assessment have been published, allowing donation only if they are unrestrictedly healthy. Eligibility criteria for related donors are less strict and vary significantly between centers. In situations where a family donor does not meet the suitability criteria for unrelated donors, involved physicians often struggle with the decision whether the matched relative is suitable for donation or not. On behalf of the Worldwide Network for Blood and Marrow Transplantation Standing Committee on Donor Issues, we intended to develop a consensus document with recommendations for donor workup and final clearance of family donors who would not be able to serve as unrelated donors because of their age or pre-existing diseases. This article covers different topics intending to support decision-making, with the goal of minimizing medical risk to the donor and protection of the recipient from transmissible diseases.

Detection of a novel variant of HLA-A*02, HLA-A*02:570, in a Taiwanese unrelated hematopoietic stem cell donor.

Two nucleotide changes at residue 142 (G → A) and residue 144 (A → C) of HLA-A*02:01:01:01 result in a novel allele, HLA-A*02:570.

Detection of a novel variant of HLA-B*07, HLA-B*07:249, in a Taiwanese unrelated hematopoietic stem cell donor.

One nucleotide replacement at residue 398 of HLA-B*07:05:01 or HLA-B*07:06 results in a novel allele, HLA-B*07:249.

A novel human leukocyte antigen (HLA) allele, HLA-DRB1*08:71, was found in a Taiwanese unrelated hematopoietic stem cell donor.

One nucleotide substitution at residue 367 of HLA-DRB1*08:03:02 results in a new allele, HLA-DRB1*08:71.

Lower dose anti-thymocyte globulin for GvHD prophylaxis results in improved survival after allogeneic stem cell transplantation.

In vivo T-cell depletion with anti-thymocyte globulin (ATG) can attenuate GvHD but may increase infection and relapse risks. ATG-Fresenius (ATG-F) at a dose of 60 mg/kg was standard GvHD prophylaxis in unrelated donor hematopoietic stem cell transplantation (HSCT) at our institution. We changed to an incremental reduced dose regimen of 35 mg/kg and extended ATG prophylaxis to include older matched-related donor transplants considered to be at higher risk of GvHD. A total of 265 adults with hematological malignancies receiving a first allogeneic HSCT after myeloablative conditioning between 2009 and 2014 were analyzed in this cohort study. Patients had either received higher dose (n=32) or lower dose ATG-F (n=88) or no ATG (n=145). ATG-F was associated with slower engraftment and less chronic GvHD, whereas no effect was noted on acute grade II-IV GvHD and relapse incidence. Transplant-related mortality (TRM) was lower and survival higher with lower dose, but not with higher dose ATG-F. Both ATG-F groups were associated with more viral reactivation, viral disease and bacterial blood stream infection, but not invasive fungal infection, and with slower immune reconstitution. The recently adopted strategy of using lower doses of ATG-F in unrelated and older age-related donor HSCT appears to reduce TRM without increasing disease relapse, leading to slightly enhanced survival.

CMV reactivation drives posttransplant T-cell reconstitution and results in defects in the underlying TCRβ repertoire

AbstractAlthough cytomegalovirus (CMV) reactivation has long been implicated in posttransplant immune dysfunction, the molecular mechanisms that drive this phenomenon remain undetermined. To address this, we combined multiparameter flow cytometric analysis and T-cell subpopulation sorting with high-throughput sequencing of the T-cell repertoire, to produce a thorough evaluation of the impact of CMV reactivation on T-cell reconstitution after unrelated-donor hematopoietic stem cell transplant. We observed that CMV reactivation drove a >50-fold specific expansion of Granzyme Bhigh/CD28low/CD57high/CD8+ effector memory T cells (Tem) and resulted in a linked contraction of all naive T cells, including CD31+/CD4+ putative thymic emigrants. T-cell receptor β (TCRβ) deep sequencing revealed a striking contraction of CD8+ Tem diversity due to CMV-specific clonal expansions in reactivating patients. In addition to querying the topography of the expanding CMV-specific T-cell clones, deep sequencing allowed us, for the first time, to exhaustively evaluate the underlying TCR repertoire. Our results reveal new evidence for significant defects in the underlying CD8 Tem TCR repertoire in patients who reactivate CMV, providing the first molecular evidence that, in addition to driving expansion of virus-specific cells, CMV reactivation has a detrimental impact on the integrity and heterogeneity of the rest of the T-cell repertoire. This trial was registered at www.clinicaltrials.gov as #NCT01012492.

A novel HLA allele, HLA-DRB1*15:116, discovered in a Taiwanese unrelated hematopoietic stem cell donor.

One nucleotide substitution at residue 127 of HLA-DRB1*15:01:01:01 results in a new allele, HLA-DRB1*15:116.