Risk associations between HLA-DPB1 T-cell epitope matching and outcome of unrelated hematopoietic cell transplantation are independent of HLA-DPA1

HLA-DP antigens are beta-alpha heterodimers encoded by polymorphic HLA-DPB1 and -DPA1 alleles, respectively, in strong linkage disequilibrium (LD) with each other. Non-permissive unrelated donor (UD)-recipient HLA-DPB1 mismatches across three different T-cell epitope (TCE) groups are associated with increased mortality after hematopoietic SCT (HCT), but the role of HLA-DPA1 is unclear. We studied 1281 onco-hematologic patients after 10/10 HLA-matched UD-HCT facilitated by the National Marrow Donor Program. Non-permissive mismatches defined solely by HLA-DPB1 TCE groups were associated with significantly higher risks of TRM compared to permissive mismatches (hazard ratio (HR) 1.30, confidence interval (CI) 1.06–1.53; P=0.009) or allele matches. Moreover, non-permissive HLA-DPB1 TCE group mismatches in the graft versus host (GvH) direction significantly decreased the risk of relapse compared to permissive mismatches (HR 0.55, CI 0.37–0.80; P=0.002) or allele matches. Splitting each group into HLA-DPA1*02:01 positive or negative, in frequent LD with HLA-DPB1 alleles from two of the three TCE groups, or into HLA-DPA1 matched or mismatched, did not significantly alter the observed risk associations. Our findings suggest that the effects of clinically non-permissive HLA-DPB1 TCE group mismatches are independent of HLA-DPA1, and that selection of donors with non-permissive DPB1 TCE mismatches in GvH direction might provide some protection from disease recurrence (read more).

Parvovirus Associated Fulminant Hepatic Failure and Aplastic Anemia Treated Successfully With Liver and Bone Marrow Transplantation. A Report of Two Cases

Aplastic anemia (AA) has been observed in nearly a third of patients undergoing liver transplantation (LT) for non-A-E fulminant hepatic failure (FHF). Few of these patients have been successfully managed with sequential LT and bone marrow transplantation (BMT). No causative agent has been identified for the FHF or AA in these reported cases. At our center, two patients, aged 15 years and 7 years, respectively, underwent sequential living-related LT and living-unrelated BMT. These patients are 10/9 years and 5/4 years post-LT/BMT. Human parvovirus B19 (HPV-B19) was established as the causative agent for FHF in both these patients by polymerase chain reaction. This report presents the first two cases associating HPV-B19 with FHF and AA who underwent sequential LT and BMT with excellent outcomes (read more)