HLA-mismatched Unrelated Donors Research Articles

Meta-Analysis of HLA-Mismatched Compared to HLA-Matched Hematopoietic Stem Cell Transplantation

Background: Mismatched unrelated donor (MMURD) transplantation is widely accepted as an alternative donor source in patients who lack a matched unrelated donor (MUD). The magnitude of risk of adverse outcomes associated with HLA mismatching in the unrelated donor setting is not known. We performed a systematic review and meta-analysis to assess the difference in outcomes of MUD transplants with those of MMURD transplants in adults with hematologic malignancies.Methods: A comprehensive search of Medline and EMBASE was performed through April 2014. Studies eligible for inclusion were published manuscripts that reported overall survival of adult patients with hematologic malignancies who underwent MUD (10 out of 10 matched at HLA-A, B, C, DRB1, and DQB1) or MMURD transplants (9 out of 10 single antigen or allele mismatch). Study selection, data extraction and quality assessment were completed independently by two reviewers, and disagreements were resolved by a third reviewer. The pooled relative risks (RR) from hazard ratios and risk ratios and 95% confidence intervals (CI) were estimated using a random-effects model (DerSimonian and Laird method). Heterogeneity was tested using the I2 statistic and Cochran Q test, and the sources of heterogeneity were evaluated using univariate meta-regression. Analysis of publication bias, sensitivity analysis, and cumulative meta-analysis were used to test reliability. Statistical analyses were performed using Stata version 13.1.Results: There were 10 studies eligible for inclusion for the primary analysis of overall mortality. Single allele or antigen MMURD transplants were associated with significantly higher risk of overall mortality compared to MUD transplants (RR 1.32, 95% CI 1.17–1.49, p<0.001). There was substantial heterogeneity across studies (I2= 59.8%, p=0.006). None of the predefined covariates, including publication year, follow-up duration, age, sex, graft source, conditioning regimen, T-cell depletion, and geographical region of study were shown to be significantly contributing to heterogeneity. There was no statistically significant evidence of publication bias by Egger’s test (p=0.082) or funnel plot analysis. Sensitivity analysis omitting each study individually did not substantially change the pooled effect estimate. Cumulative meta-analysis indicated no change in the magnitude of the pooled effect with time.MMURD transplants were associated with significantly lower disease-free survival compared to MUD transplants (n=6; RR 1.20, 95% CI, 1.08–1.33, p=0.001; I2= 0.0%). The pooled effect estimate for acute grade II-IV graft-versus-host disease (GVHD) was borderline significant (n=4; RR 1.23, 95% CI, 0.99–1.53, p=0.061; I2= 0.0%). The pooled effect estimate for chronic GVHD was not significant (n=3; RR 1.08, 95% CI, 0.76–1.54, p=0.679; I2= 32.1%).Conclusion: HLA-mismatched unrelated donor transplants are associated with significantly higher risk of overall mortality compared to HLA-matched unrelated donor transplants. The principal cause of adverse outcomes does not however appear to be completely related to excess GVHD. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Incidence, risk factors and clinical outcome of leukemia relapses with loss of the mismatched HLA after partially incompatible hematopoietic stem cell transplantation.

Genomic loss of the mismatched human leukocyte antigen (HLA) is a recently described mechanism of leukemia immune escape and relapse after allogeneic hematopoietic stem cell transplantation (HSCT). Here we first evaluated its incidence, risk factors and outcome in 233 consecutive transplants from partially HLA-mismatched related and unrelated donors (MMRD and MMUD, respectively). We documented 84 relapses, 23 of which with HLA loss. All the HLA loss relapses occurred after MMRD HSCT, and 20/23 in patients with acute myeloid leukemia. Upon MMRD HSCT, HLA loss variants accounted for 33% of the relapses (23/69), occurring later than their 'classical' counterparts (median: 307 vs 88 days, P<0.0001). Active disease at HSCT increased the risk of HLA loss (hazard ratio (HR): 10.16; confidence interval (CI): 2.65-38.92; P=0.001), whereas older patient ages had a protective role (HR: 0.16; CI: 0.05-0.46; P=0.001). A weaker association with HLA loss was observed for graft T-cell dose and occurrence of chronic graft-versus-host disease. Outcome after 'classical' and HLA loss relapses was similarly poor, and second transplantation from a different donor appeared to provide a slight advantage for survival. In conclusion, HLA loss is a frequent mechanism of evasion from T-cell alloreactivity and relapse in patients with myeloid malignancies transplanted from MMRDs, warranting routine screening in this transplantation setting.

Are Alternative Donors Really Still “Alternative?”

Are Alternative Donors Really Still “Alternative?”

The Influence Of Anti-HLA Antibodies On Engraftment and Donor's Chimerism Following Allogeneic Hematopoietic Stem Cell Transplantation From HLA-Mismatched Unrelated Donors

Introduction Although anti-HLA Antibodies (Abs) are considered an important factor of graft failure in solid organ transplants, their role in allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still undiscovered. Large polymorphism and immunogenicity of HLA-antigens and heterogeneity of anti-HLA Abs warrant the need of such investigation. The purpose of this study was to define the presence of anti-HLA Abs before allo-HSCT from HLA-mismatched unrelated donors and their impact on engraftment and post-transplant full donor’s chimerism. Material and Methods 70 HLA-mismatched donor/recipient pairs entered the study. Indication for allo-HSCT was: ALL, AML, CML, SAA, PNH, MDS and CLL. Preparative regimen was myeloablative in 68pts (97%) and reduced in 2pts (2.3%). Standard GVHD prophylaxis consisted of cyclosporine, methotrexate and pre-transplant anti-thymocyte globulin (69pts) or Alemtuzumab (1pt). HLA A,B,C,DR,DQ alleles were PCR-typed. Single HLA-antigen was mismatched in 46pts, single HLA-allele in 16pts, double antigens or alleles in 2 pts and another 2 pts had combined antigenic/allelic HLA mismatch. Anti-HLA A,B,C,DR,DQ,DP Abs were identified in sera collected prior to the conditioning treatment with use of automated DynaChip assay utilizing microchips bearing purified class I and class II HLA antigens. Post-transplant chimerism was analyzed using STR-PCR method at 30, 100-days and 1-year after allo-HSCT. Results Anti-HLA Abs pre-formed before allo-HSCT were detected in 32pts: against class I, II or both in 13(18.6%), 7(10%) and 12(17.1%) pts. Anti-HLA Abs were detected after allo-HSCT in 49pts: against class I, II or both in 22(32.4%), 7(10.3%) and 20(29.4%) pts, respectively. Anti-HLA Abs directed against the mismatched HLA antigens were observed in 4 pts before allo-HSCT. Although no Abs specific to mismatched HLA alleles were detected, Abs belonging to the same Cross-Reactive Groups (CREGs) were present in 5pts. No graft failure has been observed (graft failure was defined as absence of neutrophil recovery by day 30 after allo-HSCT or loss of donor’s chimerism). The detection of anti-HLA Abs before allo-HSCT was associated with decrease of post-transplant donor’s chimerism (18/31 vs 11/35, p=0.03). Anti-HLA Abs had no significant impact on engraftment of platelets and neutrophils. The median time to neutrophils engraftment was 16.9 days (range 7-31 days) in pts with and 18.9 days (range 13-30 days) in pts without anti-HLA Abs (p=0.188). The median time to platelets engraftment was 16.9 days (range 9-31 days) in patients with and 18.3 days (range 10-32 days) in pts without anti-HLA Abs (p=0.274). Conclusions Our preliminary results indicate, that anti-HLA Abs are present before transplantation in mismatched allo-HSCT recipients. They influence the post-transplant full donor’s chimerism, but they did not influence engraftment and graft failure. Disclosures: No relevant conflicts of interest to declare.

Outcome Of Patients With IPSS Intermediate (int) Or High Risk Myelodysplastic Syndrome (MDS) According To Donor Availability: A Multicenter Prospective Non Interventional Study For The SFGM-TC and GFM

▪ BackgroundAllogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for MDS patients (pts). Due to transplant-related mortality, only pts with short life expectancy are referred to HSCT, usually those with IPSS int-2 or high risk. The aim of this prospective study was to compare outcome in candidates for HSCT according to donor availability: no donor, HLA-matched sibling donor, 10/10 HLA-matched unrelated donor and 9/10 HLA-mismatched unrelated donor. MethodSFGM-TC and GFM centers that had agreed on general recommendations concerning the management of MDS pts participated to the study (16 centers). Transplant indications were int-2 or high IPSS, int-1 with refractory thrombocytopenia or proliferative CMML. Pts were registered in this study if older than 50 years, when they acquired an indication for HSCT and in the absence of comorbidity contraindicating HSCT. A donor research was initiated at registration including HLA-matched sibling donor, HLA-matched unrelated donor (10/10) or mismatched donor for one allele. Other alternative donors (mismatched unrelated cord blood or > 1 mismatched donor) were not accepted. Transplantation was scheduled upfront if bone marrow blasts < 10% at inclusion or after treatment with AML like anthracycline-aracytine chemotherapy (CT) or azacitidine (AZA) if marrow blasts > 10% ideally within 6 months if a donor was identified. Recommended reduced intensity conditioning regimen consisted in fludarabine, busulfan and anti-thymoglobulin with peripheral stem cells (PB) as source of stem cells. Characteristics of pts and disease were compared within 3 groups: no donor, HLA-matched donor (sibling or 10/10), HLA-one mismatched donor (9/10). Overall and disease free survivals (OS, DFS) were compared using Kaplan Meier estimates. Cumulative incidences of complete remission and disease-related mortality were compared using Gray-test. ResultsFrom April 2007 to January 2013, 163 pts were included: 34 (21%) pts had no donor; 115 (71%) pts had an HLA-matched donor (34% sibling and 37% unrelated) and 14 (9%) pts had an HLA mismatched donor. Groups were well-balanced for age, gender, time from diagnosis to inclusion, WHO classification, bone marrow blasts at time of inclusion, cytogenetic (IPSS) and IPSS classification. WHO classification at time of inclusion was: AML post MDS in 12, RAEB1 in 29, RAEB2 in 82, CMML1 or 2 in 20, RCMD in 14 and other MDS in 6 pts. Cytogenetics were favorable in 49 (30%), intermediate in 37 (23%) and poor in 74 (45%) pts. IPSS was int-1 for 8%, int-2 for 69% and high for 23% of pts.Median follow-up was 38 months. 117 pts were treated by AZA and 40 by CT. Bone marrow blasts < 10% were achieved in 68% and 57% for pts without and with donor, respectively. 69% of pts with HLA-identical donor and 57% of those with HLA-mismatched donor were transplanted. Some pts with donors were not transplantation because of excess of marrow blasts in most pts (> 10% in 3, > 20% in 20 pts), comorbidities contraindicating the transplantation acquired after inclusion (9 pts), early deaths (7 pts) and other causes in 3 pts. Four other pts scheduled for transplantation have not been transplanted yet. Probability of complete remission 12 months after inclusion was: 39% (95% CI: 22-55), 49% (95%CI: 40-58) and 46% (95%CI: 17-71) for pts without a donor, with an HLA-compatible donor and with HLA-mismatched donor. Disease-related mortality at 48 months was not significantly different in the 3 groups: 50 % (95%CI: 29-68), 38% (95%CI: 27-49), 51% (95%CI: 17-77). DFS was also not different in 3 groups: 18% (95%CI: 7-44), 25% (95%CI: 16-37) and 9% (95%CI: 1-57). In contrast, OS at 48 months was better in pts with HLA-compatible donor than in pts without donor or those with HLA-mismatched donor: 35% (26-49), 17% (6-43) and 8% (1-55), respectively, p=0.011 (Figure 1). The poor survival observed in pts transplanted with an HLA-mismatched donor may be due to their small number and requires further analysis in a larger cohort. Outcome was not different in pts receiving PB from HLA-matched sibling or from HLA 10/10 matched unrelated donor. [Display omitted] ConclusionIn a prospective study, we observed that int-2 or high risk MDS pts with a HLA-matched donor have an improved life expectancy as compared to pts without donor. This study confirmed that they should be referred to the transplantation before acquisition of comorbidity contraindicating HSCT. Disclosures:No relevant conflicts of interest to declare.

Prognostic Importance Of Thrombocytopenia On Day 60 After Allogeneic Stem Cell Transplantation For Acute Leukemia

BackgroundAlthough thrombocytopenia is a common complication after allogeneic stem cell transplantation (SCT) and is a notable prognostic factor in patients with chronic graft-versus-host disease, the impact of thrombocytopenia in early period after SCT on the outcome is not clearly identified. In this study, we retrospectively assessed the association of thrombocytopenia after SCT with the result of transplantation in patients with acute leukemia. Patients and MethodsThis study included patients with acute leukemia who underwent SCT at our institute between 2000 and 2010. Patients who received repeat transplantation, relapsed, or died within 60 days after the first SCT were excluded. Thrombocytopenia was defined as the level of platelet count < 50 x 109/L on day 60 after SCT. Factors associated with thrombocytopenia were studied and the impact of thrombocytopenia on transplant outcomes was also analyzed in this study. ResultsThere were 182 patients with acute leukemia (119 with acute myeloid leukemia and 63 with acute lymphoblastic leukemia), with median age was 43 years (range: 16-65 years). The disease risk at transplantation was standard risk in 89 patients and high risk in 93. Myeloablative conditioning (MAC) was employed for 139 patients and reduced-intensity conditioning (RIC) was done for 43. Bone marrow (BM) from related or unrelated donors was transplanted in 121 patients, as well as peripheral blood stem cell (PB) from related donors in 29 and cord blood (CB) in 32. Transplantation was done from HLA-matched related donors in 60 patients, HLA-mismatched related donors in 17, HLA-matched unrelated donors in 59, and HLA-mismatched unrelated donors in 46. Cumulative incidence of platelet recovery (≥50 x 109/L) on day 60 by grafts was 70% for BM, 69% for PB, and 50% for CB (p=0.11). Factors significantly associated with thrombocytopenia on day 60 after SCT were unrelated donor (vs related donor: 41% vs 25%, p=0.023), MAC (vs RIC: 38% vs 21 %, p=0.038), HLA-mismatch (vs HLA-match: 51% vs 25%, p<0.001), and cumulative incidence of grade II-IV acute GVHD (vs grade 0-I: 64% vs 42%, p=0.002). On multivariate analysis, older age, MAC, HLA-mismatch, and acute GVHD were significantly correlated with thrombocytopenia. After a median follow-up of 68.2 months (range: 4.7-144 months), 2-year overall survival (OS) was 58%. The cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) at 2 years was 31% and 15% respectively. The 2-year OS, CIR, and NRM at 2 years in patients with and without thrombocytopenia on day 60 were 40% and 68% (p<0.001), 34% and 30% (p=0.921), and 28% and 8% (p<0.001), respectively. Multivariate analysis showed that thrombocytopenia (relative to non-thrombocytopenia: HR 2.27 [95% CI 1.40-3.68], p<0.001) and high disease risk (relative to standard risk: HR 2.80 [95% CI 1.73-4.54], p<0.001) were significantly associated with worse 2-year OS. Furthermore, high disease risk (relative to standard risk: HR 3.41 [95% CI 1.87-6.22], p<0.001) for CIR, and thrombocytopenia (relative to non-thrombocytopenia: HR 2.71 [95% CI 1.23-6.00], p=0.013) and grade II-IV acute GVHD (relative to grade 0-I: HR 2.36 [95% CI 1.12-4.99], p=0.025) for NRM were also independent predictors on multivariate analysis. ConclusionsVarious factors might influence on thrombocytopenia following SCT, but our results suggest that thrombocytopenia on day 60 is a good predictor for complications and survival in patients receiving SCT for acute leukemia. Disclosures:No relevant conflicts of interest to declare.

Prospective Evaluation Of Alternative Donor Availability In 708 Patients: Improved Allograft Access With Enlarging CB Inventory For All Patients Including Racial and Ethnic Minorities

BackgroundAvailability of suitably HLA-matched adult donors is a major barrier to allogeneic transplantation. Cord blood (CB) extends transplant access to many patients including minorities. However, some patients have no suitable unrelated donors (URDs) or CB grafts. Moreover, HLA-match is a critical determinant of URD & CB transplantation (CBT) outcome, & some patients will only have access to mismatched URDs &/or highly HLA-mismatched CB units. We evaluated if URD/ CB access has improved with increased size of URD registries & global CB inventories. MethodsWe prospectively collected ancestry data on patients undergoing searches between 10/2005-6/2013, & analyzed the availability of 9-10/10 HLA-matched URDs or 4-6/6 HLA-A,-B antigen, -DRB1 allele matched CB units by recipient ancestry in patients with hematologic malignancies. 10 HLA-allele matched URDs were given priority if available; otherwise HLA-mismatched URDs or double-unit CB grafts were chosen. Given our minimum CB total nucleated cell (TNC) dose criteria was increased from 1.5 to 2.0 x 107/kg/unit in 2010, this analysis was restricted to units with a cryo. TNC dose ≥ 2.0. Also, as high-resolution typing was performed in all CB units & considered in unit selection since 2012, availability of CB units by 10-allele match was evaluated. Finally, given the global public CB inventory reached 500,000 units in 2011, URD/CB availability was compared between early (10/2005-12/2010) & recent (1/2011-6/2013) periods. Results708 patients were evaluated including 223 (31%) of non-European origins. 511 (72%) patients received an URD transplant, 159 (22%) received a CBT, & 38 (5%) had no graft. URD recipients were predominantly of European ancestry (n = 400, 78%) whereas only 77 (48%) of CBT recipients had European origins. 30/38 (79%) patients without any graft were non-European with over half (n = 20) being of African ancestry. “No graft” patients had a higher weight (median 93 kg, range 50-151) than CBT recipients (median 68 kg, range 8-133), p < 0.001. The availability of grafts for Europeans & non-Europeans during the early versus recent time periods is shown (Table). Patient ancestry distribution was equal during the periods. The majority of Europeans received a 10/10 URD transplant in both periods & very few had no graft (< 1% recently). However, only approximately half of non-Europeans undergoing URD transplant received a 10/10 match. Moreover, of non-Europeans overall, only 29/129 (22%) had a 10/10 URD in the early period, & this has not improved recently [28/94 (30%), p = 0.28]. The percentage of non-Europeans receiving CB units with a ≥ 5/6 donor-recipient HLA-match has not improved (data not shown). However, while only 28% of non-Europeans received a CB graft consisting of ≥ 6/10 HLA-matched units in the early period, this donor-recipient HLA-match rate improved to 69% recently (p < 0.001), a rate similar to that of European patients. The percentage of non-Europeans with no graft has decreased from 17% to 8.5% (p = 0.08). Furthermore, while African patients were the largest group among no graft patients (68% in early period & 63% recently), of African patients without an URD, 16/31 (52%) had a CB graft in the early period versus 15/20 (75%) recently, p = 0.14.TableN in Early Time PeriodN in Recent Time Period(n = 424, 60% of total patients)(n = 284, 40% of total patients)Europeans (n = 485)N = 295N = 190URD: 246 [175/246 (71%) received 10/10]URD: 154 [117/154 (76%) received 10/10]CB: 42 [20/42 (48%) ≥ 6/10]CB: 35 [19/35 (54%) ≥ 6/10]No graft: 7 [7/295 (2%) of Europeans]No graft: 1 [1/190 (0.5%) of Europeans]Non-Europeans (n = 223)N = 129N = 94URD: 61 [29/61 (48%) 10/10]URD: 50 [28/50 (56%) 10/10]CB: 46 [13/46 (28%) ≥ 6/10]CB: 36 [25/36 (69%) ≥ 6/10]No graft: 22 [22/129 (17%) non-Europeans]No graft: 8 [8/94 (8.5%) of non-Europeans] ConclusionVery few Europeans do not have an URD &/or CB graft. However, URDs are a poor donor source for patients with non-European ancestry. By contrast, CB is a critically important stem cell source for minorities, & transplantation of units with higher rates of 10 HLA-allele match is now frequently possible likely due to a bigger inventory & the use of high-resolution matching. Our analysis suggests CB availability in non-Europeans has improved. However, additional measures are required to extend graft access for African ancestry patients. Disclosures:No relevant conflicts of interest to declare.

Pathogenesis of graft-versus-host disease: innate immunity amplifying acute alloimmune responses

In addition to reduced-intensity conditioning, which has expanded the eligibility for hematopoietic cell transplantation (HCT) to older patients, increased availability of alternative donors, including HLA-mismatched unrelated donors, has increased access to allogeneic HCT for more patients. However, acute graft-versus-host disease (GVHD) remains a lethal complication, even in HLA-matched donor-recipient pairs. The pathophysiology of GVHD depends on aspects of adaptive immunity and interactions between donor T-cells and host dendritic cells (DCs). Recent work has revealed that the role of other immune cells and endothelial cells and components of the innate immune response are also important. Tissue damage caused by the conditioning regimen leads to the release of exogenous and endogenous "danger signals". Exogenous danger signals called pathogen-associated molecular patterns and endogenous noninfectious molecules known as damage-associated molecular patterns (DAMPs) are responsible for initiating or amplifying acute GVHD by enhancing DC maturation and alloreactive T-cell responses. A significant association of innate immune receptor polymorphisms with outcomes, including GVHD severity, was observed in patients receiving allogeneic HCT. Understanding of the role of innate immunity in acute GVHD might offer new therapeutic approaches.

Escalating-dose HLA-mismatched DLI is safe for the treatment of leukaemia relapse following alemtuzumab-based myeloablative allo-SCT

Although the feasibility of using HLA-mismatched unrelated donors as an alternate graft source for haematopoietic SCT (HSCT) has been shown, little is known about the safety of HLA-mismatched DLI for the treatment of relapse. We examined the outcome of 58 consecutive leukaemia patients who received escalating-dose DLI for treatment of relapse after alemtuzumab-conditioned myeloablative unrelated donor HSCT at our institution. High-resolution HLA typing on stored DNA samples revealed mismatches in 28/58 patients who were considered HLA-matched at the time of transplantation. Following DLI from HLA-matched (10/10) (n=30) or -mismatched (7-9/10) (n=28) unrelated donors, we found no significant difference in the incidence of acute GVHD (17.2% versus 23.1%, P=0.59), probability of remission at 3 years (62.1% versus 63.9%, P=0.89) or 5-year OS (89.8% versus 77.7%, P=0.22). We conclude that escalating-dose DLI can be safely given to HLA-mismatched recipients following T-depleted myeloablative HSCT.

Mapping MHC haplotype effects in unrelated donor hematopoietic cell transplantation

AbstractLife-threatening risks associated with HLA-mismatched unrelated donor hematopoietic cell transplantation limit its general application for the treatment of blood diseases. The increased risks might be explained by undetected genetic variation within the highly polymorphic major histocompatibility complex (MHC) region. We retrospectively assessed each of 1108 MHC region single nucleotide polymorphisms (SNPs) in 2628 patients and their HLA-mismatched unrelated donors to determine whether SNPs are associated with the risk of mortality, disease-free survival, transplant-related mortality, relapse, and acute and chronic graft-versus-host disease (GVHD). Multivariate analysis adjusted for HLA mismatching and nongenetic variables associated with each clinical end point. Twelve SNPs were identified as transplantation determinants. SNP-associated risks were conferred by either patient or donor SNP genotype or by patient-donor SNP mismatching. Risks after transplantation increased with increasing numbers of unfavorable SNPs. SNPs that influenced acute GVHD were independent of those that affected risk of chronic GVHD and relapse. HLA haplotypes differed with respect to haplotype content of (un)favorable SNPs. Outcome after HLA-mismatched unrelated donor transplantation is influenced by MHC region variation that is undetected with conventional HLA typing. Knowledge of the SNP content of HLA haplotypes provides a means to estimate risks prior to transplantation and to lower complications through judicious selection of donors with favorable MHC genetics.

Successful transplantation of ethnically mismatched cord blood in a boy with atypical chronic myeloid leukemia

In the present study, we describe unrelated umbilical cord blood transplantation (CBT) in a 7-year-old Taiwanese boy with atypical chronic myeloid leukemia (BCR-ABL 1 negative). Physical examination was notable for splenomegaly. Cytogenetic analyses from the bone marrow revealed a t(3;5)(p21;q31) translocation. The patient then underwent CBT from an HLA-mismatched (two loci by serotype, three loci by genotype) unrelated donor of Caucasian origin. Times to neutrophil and platelet engraftment were 21 and 62days post-transplant, respectively. Acute graft-versus-host disease following transplantation was minimal. The patient remains in continuing hematological remission with full donor chimerism 28months after transplantation.

Anti-HLA Antibodies in Allogeneic Hematopoietic Stem Cell Transplantation From HLA-Mismatched Unrelated Donors

AbstractAbstract 4475 Introduction:Anti-HLA Antibodies (Abs) are considered an important factor in solid organ transplants and transfusion medicine, but role of humoral arm of immunological response to HLA antigens in allogeneic hematopoietic stem cell transplantation (allo-HSCT) is unknown. Large polymorphism and immunogenicity of HLA-antigens and heterogeneity of anti-HLA Abs warrant the need of such investigation. The purpose of this study was to define presence and profiles of anti-HLA Abs detected before or after allo-HSCT from HLA-mismatched unrelated donors and their impact on allo-HSCT results. Material and methods:35 HLA-mismatched donor/recipient pairs entered the study. Indication for allo-HSCT was: ALL (7pts), AML(18pts), CML(5pts), SAA(2pts), CLL(1pt), MDS(1pt) and PNH (1pt). Preparative regimen was myeloablative in 33pts (94.3%) and reduced in 2pts (5.7%). Standard GVHD prophylaxis consisted of cyclosporine, methotrexate and pre-transplant anti-thymocyte globulin (34pts) or Alemtuzumab (1pt). HLA A, B, C, DR, DQ alleles were PCR-typed. 21(60%) pts had mismatch of single HLA-antigen: A-4(11.4%), B-1(2.8%), C-13(37%), DQ-3(8,5%); 10(28.5%) pts had mismatch of single HLA-allele: A-3(8.5%), B(11.4%), DQ-3(8.5%); 4 pts had double antigenic (A+C and A+DQ) or combined antigenic/allelic (A/B and C/A) HLA mismatches. Anti-HLA A, B, C, DR, DQ, DP Abs were identified in sera collected before start of the conditioning treatment and +30 days, +100 days and 1 year after allo-HSCT with use of automated DynaChip assay utilizing microchips bearing purified class I and class II HLA antigens. Results:Anti-HLA Abs pre-formed before allo-HSCT were detected in 17(48.5%) pts: against class I, II or both in 6(35%), 4(24%) and 7(41%) pts. Anti-HLA Abs were detected after allo-HSCT in 25(71.4%) pts, against class I, II or both in 9(36%), 3(12%) and 13(52%) pts, respectively. In 7 pts anti-HLA Abs were not detected neither before nor after allo-HSCT. Anti-HLA Abs directed against the mismatched HLA antigens were observed in 4 pts before and in 10 pts after allo-HSCT, no anti-HLA Abs specific against mismatched alleles were detected. Allo-HSCT results obtained in studied subgroups are presented in the Table below:before allo-HSCTafter allo-HSCTpresentabsentpresentabsentAnti-HLA Abs % (number of pts)48.5% (17)51.5% (18)71.4% (25)28.6% (10)Acute GVHD grade III-IV5.8% (1)5.5% (1)4% (1)10% (1)Chronic GVHD extensive29.4% (5)27.7% (5)33% (8)20% (2)100% donor chimerism88% (15)100% (18)96% (24)100% (10)Chimerism decrease <100%41.1% (7)27.7% (5)44% (11)10% (1)Relapse11.7% (2)16.6% (3)16% (4)10% (1)Death29.4% (5)33.3% (6)28% (7)40% (4)Graft failure5.8% (1)000 Conclusions:Our preliminary results indicate that anti-HLA Abs are present pre- or post-transplant in mismatched allo-HSCT recipients and may be potentially responsible for the occurrence of complications, what needs to be further investigated and analyzed. Disclosures:No relevant conflicts of interest to declare.

Risk Factors to Develop Sclerotic Chronic GvHD After Allogeneic HSCT: Preliminary Results of a Multicentre Retrospective study From the Société Française De Greffe De Moelle Et De Thérapie Cellulaire (SFGM-TC)

AbstractAbstract 1947 IntroductionSclerotic cGvHD is one of the most severe complications after allogeneic hematopoietic stem cell transplantation (HSCT). The sclerotic skin manifestations of cGvHD result from inflammation and fibrosis of the dermis, subcutaneous tissue, or muscular fascia, leading to functional disability. Risk factors associated with sclerotic cGvHD remain not well studied. TBI, PBSC, female recipient, and prior severe skin acute GvHD were identified as factors associated with an increased risk of sclerotic cGvHD in a large previous retrospective study from Seattle (n=986 patients) which was presented at the ASH 2011 meeting. ObjectiveIn the aim to validate the previous risk factors in France, we have conducted this retrospective multicentric analysis. We present here the preliminary results from four centers, seven are expected in the next months. Between 2005 and 2010, 437 consecutive patients who received systemic therapy for chronic GvHD after a first allogeneic HSCT were included. Chronic GvHD was diagnosed by the NIH consensus criteria. Sclerotic GvHD was defined by manifestations of cutaneous sclerosis, fasciitis or joint contracture in the medical record. Analyses to determine risk factors included as variable patient and donor age, kind of donor, HLA matching, diagnosis, stem cell source, patient and donor gender, intensity of conditioning regimen, use of total body irradiation (TBI) or antithymocyte globulin (ATG) in the conditioning regimen, and prior acute GvHD. ResultsAll patients had hematological malignancies, the median age is 45 (17–65), 227 patients (52%) had HLA-matched related donors, 125 (29%) had HLA-matched unrelated donors, 48 (11%) had HLA- 9/10 unrelated donors and 37 (8%) had one or two cord blood unit (HLA-4/6 or 5/6 matched). The median time from allogeneic HSCT to chronic GvHD was 6.5 (1.8–41.5) months; 69 patients (15.7%) presented sclerotic features at initial diagnosis or after the onset of chronic GvHD.The cumulative incidence of sclerotic cGvHD was 12% (95%CI, 11–13.5) at 5 years after onset of chronic GvHD (Figure). From the 69 patients who experienced sclerotic cGvHD, 49 patients (71%) had HLA-matched related donors, 19 patients (27.5%) had HLA-matched unrelated donors, and 1 patient (1.5%) had HLA-mismatched unrelated donor. In univariate analysis, we found more sclerotic cGvHD in patients who had multiple myeloma (p=0.018); this effect seems to be associated with the prophylaxis for GvHD with CsA alone. There was no effect of TBI or intensity of conditioning. There was more sclerotic GvHD in female recipient (p=0.032) and for patients who had an unrelated donor (p=0.0028).In multivariate analysis (Table), factors associated with an increased risk of sclerotic cGvHD were female recipient, patients with unrelated donor, and patients with previous aGvHD. Cord blood as stem cell source was associated with a lower risk of sclerotic GvHD. Prophylaxis of GvHD with CsA alone showed a trend to a higher risk. At the last follow-up, of the 69 patients, 51 (74%) were alive and 10 (14.5%) died from cGvHD. ConclusionIn this intermediate analysis, we found that female recipient, unrelated donor, previous aGvHD are risk factors for developing sclerotic cGvHD. Moreover, we found that cord blood as stem cell source is a protector factor. Study of GvHD prophylaxis, ABO matching, type of HLA-mismatching, acute skin GvHD is ongoing on the whole cohort (n= 1587 patients from 7 centers) and results will be communicated later.After the final analysis on the whole cohort we would like to establish a score risk of sclerotic cGvHD in the goal to conduct a prospective study in France with a prophylactic treatment for high risk patients.TableMultivariate analysisHRpStem cells source and conditioning intensityMAC + Bone marrow1.0RIC + Bone marrow2.03 (0.39–10.6).4MAC + Cord blood0.0.00001RIC + Cord blood0.68 (0.02–18.01).82MAC + PBSC0.32 (0.081–1.28).11RIC + PBSC1.15 (0.5–2.5).73HLA and DonorMatched related1.0Matched unrelated0.04 (0.011–0.181).00001Mismatched unrelated0.62 (0.13–2.7).53Patient ageNSDonor ageNSSexmatchingMale to male1.0Female to female2.7 (1.2–6.06).016Female to male1.8 (0.78–4.33).16Male to female1.44 (0.67–3.13).34Disease diagnosisNSATG in conditioningNSTBI in conditioning1.35 (0.69–2.64).38Prior acute GvHD1.8 (0.9–3.36).064NS= not statistically significant. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Influence of Stem Cell Source On GvH and NRM: Comparison of 10/10 HLA-Matched Unrelated Donor (MUD) with 9/10 HLA-Mismatched Unrelated Donor (MMUD) and Unrelated Cord Blood (UCB) Transplants.

AbstractAbstract 3135▪▪This icon denotes a clinically relevant abstract Background:When an HLA-matched donor is not available for allogeneic Hematopoietic Stem Cell Transplantation (HSCT), the use of an alternative HLA-mismatched stem cell source may be considered. In Europe, HLA compatibility for HSCT is calculated for 10 alleles (HLA-A, -B, -C, -DRB1, -DQB1). The aim of this study was to retrospectively compare outcomes after transplantation from 10/10 HLA-MUD, 9/10 HLA-MMUD and UCB performed at the Hospital Saint Louis (Paris, Fr). Methods:Patients receiving a first allogeneic transplantation from a 10/10, 9/10 UD or UCB from 2000 to 2011 were included.High resolution HLA typing was performed by PCR SSO and SSP for HLA loci: A, B, C, DRB1 and DQB1. The following variables were studied as risk factors for transplant outcomes: disease, disease risk (standard/high risk), age at transplant, gender, donor/recipient sex-matching, ABO matching, donor/recipient CMV status, conditioning regimen, and use of anti-thymoglobulin (ATG). Results:355 consecutive patients with hematologic malignancies were analyzed. One hundred and ninety-six were transplanted with MUD, 84 with MMUD (mismatches for HLA-A: 16%, -B: 16%, -C: 39%, -DRB1: 8%, -DQB1: 21%) and 75 with UCB (52% with single and 48% with two UCB unit; 87% of all UCB transplants were 4–6/6 HLA-matched). Median patient age was 31 (range: 5–55). Patient characteristics differed between the 3 groups: (i) median age at transplant: 36 in MUD, 31 in MMUD, 22 in UCB (p<0.0001), (ii) high risk disease: 37%, 51%, 68% (p<0.0001), (iii) CMV negative donor/positive recipient: 31%, 36%, 60% (p<0.0001), (iv) use of ATG: 37%, 64%, 55% (p<0.0001).Cumulative incidences of grade II-IV and grade III-IV acute GvHD disease (aGvHD) were 61% (66% for MUD, 60% for MMUD and 48% for UCB) and 17% (17%, 24% and 15%), respectively. Three-year cumulative incidence of chronic GvHD (cGvHD) was 46% (51% for MUD, 49% for MMUD and 29% for UCB). Three-year NRM was 34% (28% for MUD, 31% for MMUD and 51% for UCB). Graft failure occurred in 15% of UCB patient, 8% in MMUD group and 3% in MUD group (significant difference between UCB and MUD: OR=5.44, 95%CI 1.93–15.3, p=0.001).Multivariate analysis is summarized in table 1. It showed that MMUD tented to have a higher incidence of aGvHD III-IV than MUD and UCB. UCB had a lower incidence of cGvHD than MMUD. No significant effect of HSCT source on NRM was demonstrated. Conclusion:Compared to MMUD, UCB-HSCT induces less cGvHD and non significantly increased NRM. Compared to MUD, MMUD and UCB-HSCT did not result in a clear increase of NRM. UCB and 9/10 HLA-MMUD are both suitable stem cell sources for patients who cannot benefit from 10/10 HLA-MUD transplant.Table 1:Multivariate analysis of outcomesAdjusted HR (p value)aGvHD II-IVaGvHD III-IVcGvHDNRM10/10 MUD11119/10 MMUD0.90 (p=0.54)1.75 (p=0.054)1.30 (p=0.18)1.18 (p=0.50)UCB0.63 (p=0.074)*0.86 (p=0.67)*0.75 (p=0.23)*1.82 (p=0.099)*CMV status D-/R-1D-/R+2.05 (p=0.001)Major ABO incompatibility: no1yes1.40 (p=0.019)ATG: no111yes0.40 (p<0.0001)0.29 (p<0.0001)0.40 (p<0.0001)*UCB vs 9/10 MMUD: HR 0.69 (p=0.22) for aGvHD II-IV, HR 0.49 (p=0.061) for aGvHD III-IV, HR 0.58 (p=0.039) for cGvHD and HR 1.53 (p=0.30) for NRM. Disclosures:No relevant conflicts of interest to declare.

Correlation Between Severity of Oral Mucositis and Both Overall and Gut Acute GvHD After High Intensity Conditioning Hematopoietic Stem Cell Transplantation.

AbstractAbstract 3057We conducted a study to examine potential associations between the maximum severity of oral mucositis (OM) and subsequent peak severity of acute graft-versus-host disease (GVHD) within 100 days after hematopoietic cell transplantation (HCT). Patients and Methods:The study cohort included 1689 consecutive patients who received high-intensity conditioning for treatment of hematological disease between 1995 and 2011 and had at least 2 oral medicine evaluations between days 5 and 15 after HCT with related or unrelated allogeneic bone marrow or growth factor-mobilized blood cells. Severity of OM was assessed prospectively according to the Oral Mucositis Index (OMI) (Schubert, et al, 1984). This index scores oral mucosal changes (atrophy, erythema, and pseudomembranous ulcerations) in 13 areas of the oral cavity. Acute GVHD was graded according to previously described criteria (Leisenring, et al, 2006). The maximum OMI scores between days 5 and 15 were divided into quartiles (0–17, 18–25, 26–39, and 40–89). Maximum OMI total score, and clinical features of erythema and ulceration were considered as a risk factor in the analysis. Survival was estimated by the Kaplan-Meier method. Cumulative incidences (CI) of overall and acute gut GVHD were estimated by standard methods, treating death as a competing risk. Cox regression was used to estimate hazard ratios for events occurring with the first 100 days after HCT, adjusting for other risk factors. Results:The cohort median age was 40 (range, 0–67) years. Of the 1689 patients, 426 (25%) were males recipients with female donors, 971 (57%) had low risk disease (i.e., CML in chronic phase, MDS/RA or MDS/RARS, or acute leukemia in remission) and 718 (43%) had high risk (all others diagnoses). 1011 patients (60%), received TBI-containing conditioning regimens, 1473 (90%) received methotrexate with a calcineurin inhibitor for GVHD prophylaxis, 866 (51%) received bone marrow, and 786 (47%) received mobilized blood cells. 651 patients (39%) had HLA-matched related donors, 552 (33%) had HLA-matched unrelated donors, and 479 (28%) had HLA-mismatched related or unrelated donors. The maximum OMI was 0–17 in 429 (25%) patients, 18–25 in 418 (25%), 26–39 in 434 (26%) and 40–89 in 408 (24%). 946 patients (56%) had grades II-IV acute GVHD, and 383 (23%) had grades III-IV GVHD. 906 patients (54%) had stage 1 gut GVHD, and 224 (13%) had stage 2–4 gut GVHD. The incidence rates of overall and gut acute GVHD according to OMI quartiles are shown in Table 1. Erythema was the clinical feature that most correlated with both acute overall and gut acute GVHD (p<0.0001). Table 2 displays the adjusted* hazard ratios (HR) for acute overall and gut GVHD according to maximum OMI. Higher maximum OMI was associated with increased mortality (p<0.0001). Conclusion:We propose that oropharyngeal injury caused by the pretransplant conditioning regimen reflects tissue injury throughout the gastrointestinal tract. Our results support the hypothesis that tissue injury caused by the conditioning regimen increases the risk of acute GVHD.Table 1:Incidence of acute overall and gut GVHD according to OMI quartileAcute GVHDMaximum Oral Mucositis Index QuartilesP0–1718–2526–3940–89Overall grade II-IV74%76%82%83%<0.0001Overall grade III-IV15%19%24%32%<0.0001Gut stage I-IV62%65%70%70%<0.0001Gut stage II-IV9%12%14%19%<0.0001Table 2:Adjusted* hazard ratios (HR) for acute overall and gut GVHD according to OMI quartileMaximum Oral Mucositis Index Quartiles0–1718–2526–3940–89(Reference)HR (95% CI)HR (95% CI)HR (95% CI)Overall grade II-IV1.01.04 (0.9–1.2)1.06 (0.9–1.2)1.19 (1.0–1.4)Overall grade III-IV1.01.23 (0.9–1.7)1.32 (1.0–1.8)1.73 (1.3–2.4)Gut stage I1.01.07 (0.9–1.3)1.15 (1.0–1.4)1.22 (1.0–1.5)Gut stage II-IV1.01.37 (0.9–2.1)1.39 (0.9–2.1)1.88 (1.2–2.9)*Adjusted for donor/patient gender, conditioning, graft source, donor relation, HLA match, and year of transplant. Disclosures:No relevant conflicts of interest to declare.

The Presence of Anti-HLA Antibodies before and after Allogeneic Hematopoietic Stem Cells Transplantation from HLA-Mismatched Unrelated Donors

Although anti-human leukocyte antigen antibodies (anti-HLA Abs) are important factors responsible for graft rejection in solid organ transplantation and play a role in post-transfusion complications, their role in allogeneic hematopoietic stem cell transplantation (allo-HSCT) has not been finally defined. Enormous polymorphism of HLA-genes, their immunogenicity and heterogeneity of antibodies, as well as the growing number of allo-HSCTs from partially HLA-mismatched donors, increase the probability that anti-HLA antibodies could be important factors responsible for the treatment outcomes. We have examined the incidence of anti-HLA antibodies in a group of 30 allo-HSCT recipients from HLA-mismatched unrelated donors. Anti-HLA Abs were identified in sera collected before and after allo-HSCT. We have used automated DynaChip assay utilizing microchips bearing purified class I and II HLA antigens for detection of anti-HLA Abs. We have detected anit-HLA antibodies against HLA-A, B, C, DR, DQ and DP, but no donor or recipient-specific anti-HLA Abs were detected in the studied group. The preliminary results indicate that anti-HLA antibodies are present before and after allo-HSCT in HLA-mismatched recipients.

Role of HLA in Hematopoietic Stem Cell Transplantation

The selection of hematopoietic stem cell transplantation (HSCT) donors includes a rigorous assessment of the availability and human leukocyte antigen (HLA) match status of donors. HLA plays a critical role in HSCT, but its involvement in HSCT is constantly in flux because of changing technologies and variations in clinical transplantation results. The increased availability of HSCT through the use of HLA-mismatched related and unrelated donors is feasible with a more complete understanding of permissible HLA mismatches and the role of killer-cell immunoglobulin-like receptor (KIR) genes in HSCT. The influence of nongenetic factors on the tolerability of HLA mismatching has recently become evident, demonstrating a need for the integration of both genetic and nongenetic variables in donor selection.

Bortezomib-Based Graft-Versus-Host Disease Prophylaxis in HLA-Mismatched Unrelated Donor Transplantation

HLA-mismatched unrelated donor (MMUD) hematopoietic stem-cell transplantation (HSCT) is associated with increased graft-versus-host disease (GVHD) and impaired survival. In reduced-intensity conditioning (RIC), neither ex vivo nor in vivo T-cell depletion (eg, antithymocyte globulin) convincingly improved outcomes. The proteasome inhibitor bortezomib has immunomodulatory properties potentially beneficial for control of GVHD in T-cell-replete HLA-mismatched transplantation. We conducted a prospective phase I/II trial of a GVHD prophylaxis regimen of short-course bortezomib, administered once per day on days +1, +4, and +7 after peripheral blood stem-cell infusion plus standard tacrolimus and methotrexate in patients with hematologic malignancies undergoing MMUD RIC HSCT. We report outcomes for 45 study patients: 40 (89%) 1-locus and five (11%) 2-loci mismatches (HLA-A, -B, -C, -DRB1, or -DQB1), with a median of 36.5 months (range, 17.4 to 59.6 months) follow-up. The 180-day cumulative incidence of grade 2 to 4 acute GVHD was 22% (95% CI, 11% to 35%). One-year cumulative incidence of chronic GVHD was 29% (95% CI, 16% to 43%). Two-year cumulative incidences of nonrelapse mortality (NRM) and relapse were 11% (95% CI, 4% to 22%) and 38% (95% CI, 24% to 52%), respectively. Two-year progression-free survival and overall survival were 51% (95% CI, 36% to 64%) and 64% (95% CI, 49% to 76%), respectively. Bortezomib-treated HLA-mismatched patients experienced rates of NRM, acute and chronic GVHD, and survival similar to those of contemporaneous HLA-matched RIC HSCT at our institution. Immune recovery, including CD8(+) T-cell and natural killer cell reconstitution, was enhanced with bortezomib. A novel short-course, bortezomib-based GVHD regimen can abrogate the survival impairment of MMUD RIC HSCT, can enhance early immune reconstitution, and appears to be suitable for prospective randomized evaluation.

Multicenter Experience Using Total Lymphoid Irradiation and Antithymocyte Globulin as Conditioning for Allografting in Hematological Malignancies

A non myeloablative conditioning with total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) was shown to protect against graft-versus-host disease (GVHD). To evaluate the effects of TLI-ATG in a multicenter study, 45 heavily pretreated patients, median age 51, with lymphoid (n = 38) and myeloid (n = 7) malignancies were enrolled at 9 centers. Twenty-eight patients (62%) received at least 3 lines of treatment before allografting, and 13 (29%) had refractory/relapsed disease at the time of transplantation. Peripheral blood hematopoietic cells were from HLA identical sibling (n = 30), HLA-matched (n = 9), or 1 antigen HLA-mismatched (n = 6) unrelated donors. A cumulative TLI dose of 8 Gy was administered from day -11 through -1 with ATG at the dose of 1.5 mg/kg/day (from day -11 through -7). GVHD prophylaxis consisted of cyclosporine and mycophenolate mofetil. Donor engraftment was reached in 95% of patients. Grade II to IV acute GVHD (aGVHD) developed in 6 patients (13.3%), and in 2 of these patients, it developed beyond day 100. Incidence of chronic GVHD (cGVHD) was 35.8%. One-year nonrelapse mortality was 9.1%. After a median follow-up of 28 months (range, 3-57 months) from transplantation, median overall survival was not reached, whereas median event-free survival was 20 months. This multicenter experience confirms that TLI-ATG protects against GVHD and maintains graft-vs-tumor effects.

Prognostic factors in patients aged 50 years or older undergoing allogeneic hematopoietic stem cell transplantation for hematologic malignancy

We retrospectively analyzed patients aged C 50 years with hematologic malignancies who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) to identify preoperative variables predicting the outcome. There were 71 patients with a median age of 57 years (range: 50-63 years) who had acute leukemia (n = 53) or myelodysplastic syndrome (n = 18). Myeloablative conditioning was done in 35 patients and 36 patients had reduced-intensity conditioning. The 5-year overall survival rate (OS), cumulative relapse rate, and non-relapse mortality rate (NRM) were 45, 24, and 33%, respectively. According to multivariate analysis, high-risk disease (HR 3.50, 95% CI 1.43-8.56, P = 0.006), a hematopoietic cell transplantation comorbidity index (HCT-CI) score ≥ 3 (HR 4.41, 95% CI 1.31-14.77, P = 0.016), and an HLA-mismatched unrelated donor (HR 4.03, 95% CI 1.46-11.10, P = 0.007) were significant predictors of worse OS. Highrisk disease was also significantly associated with a higher cumulative relapse rate (HR 4.59, 95% CI 0.94-6.92, P = 0.065). Furthermore, an HCT-CI score ≥ 3 (HR 3.02, 95% CI 1.01-20.78, P = 0.048) and an HLA-mismatched unrelated donor (HR 3.02, 95% CI 1.04-8.74, P = 0.042) were risk factors for NRM. These results suggest that the disease risk, HCT-CI score, and donor type/histocompatibility are prognostic factors for elderly patients, while the conditioning regimen and age are not predictors.