The impact of donor-specific anti-human leukocyte antigen antibodies in salvage haploidentical hematopoietic cell transplantation with posttransplant cyclophosphamide in patients with nonmalignant disorders

HLA-haploidentical stem cell transplantation in children with inherited bone marrow failure syndromes: A retrospective analysis on behalf of EBMT severe aplastic Anemia and pediatric diseases working parties

Haploidentical stem cell transplantation (haplo-SCT) represents the main alternative for children with inherited bone marrow failure syndrome (I-BMF) lacking a matched donor. This retrospective study, conducted on behalf of the EBMT SAAWP and PDWP, aims to report the current outcomes of haplo-SCT in I-BMFs, comparing the different in vivo and ex vivo T-cell depletion approaches. One hundred and sixty-two I-BMF patients who underwent haplo-SCT (median age 7.4 years) have been registered. Fanconi Anemia was the most represented diagnosis (70.1%). Based on different T-cell depletion (TCD) approaches, four categories were identified: (1) TCRαβ+/CD19+-depletion (43.8%); (2) T-repleted with post-transplant Cyclophosphamide (PTCy, 34.0%); (3) In-vivo T-depletion with ATG/alemtuzumab (14.8%); (4) CD34+ positive selection (7.4%). The cumulative incidences (CI) of neutrophil and platelet engraftment were 84% and 76% respectively, while that of primary and secondary graft failure was 10% and 8% respectively. The 100-day CI of acute GvHD grade III-IV(95% CI) was 13%, while the 24-month CI of extensive chronic GvHD was 4%. After a median follow-up of 43.4 months, the 2-year overall survival(OS) and GvHD/Rejection-free Survival (GRFS) probabilities are 67% and 53%, respectively. The TCR CD3+αβ+/CD19+ depletion group showed a significantly lower incidence of both acute and chronic GvHD and higher OS (79%; p0.013) and GRFS (71%; p < .001), while no significant differences in outcomes have been observed by different diagnosis and conditioning regimens. This large retrospective study supports the safety and feasibility of haplo-SCT in I-BMF patients. TCRαβ+/CD19+ depletion offers higher chances of patients' survival, with a significantly lower risk of severe a- and c-GvHD in I-BMFs compared to other platforms.

Umbilical Cord Blood Transplantation for Myelodysplastic Syndromes with Donor-Specific Anti-HLA Antibodies against HLA-DP

The presence of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) against anti-HLA-A, -B, -C, and -DRB1 in HLA-mismatched hematopoietic stem cell transplantation (HSCT) is associated with graft failure. DSAs against HLA-A, -B, -C, and -DRB1 with a mean fluorescence intensity (MFI) of greater than > 1,000 was shown to increase the risk of graft failure in single-unit umbilical cord blood transplantation (UCBT). Nevertheless, the impact of DSAs against HLA-DP or -DQ on transplantation outcomes is not fully understood. In this report, we present a case of UCBT in a patient with myelodysplastic syndrome who was positive for DSAs against HLA-DP with MFI of 1,263 before UCBT but successfully achieved neutrophil engraftment. If HLA-DP or -DQ is mismatched in UCBT, evaluating DSAs against HLA-DP or -DQ is crucial to avoid graft failure. However, the criteria for DSAs against HLA-A, -B, -C, and -DRB1 may not be directly applicable to those against HLA-DP or -DQ.

Effects of donor-specific antibodies on engraftment and long-term survival after allogeneic hematopoietic stem cell transplantation-A systematic review and meta-analysis

The presence of donor-specific antibodies (DSAs) have been reported to be associated with an increased risk of primary graft failure following allogeneic hematopoietic stem cell transplantation (allo-HSCT), but its effects on the time to engraftment and long-term outcomes remain unclear. We performed a systematic review and meta-analysis of studies investigating the impact of DSAs on engraftment and long-term survival of patients undergoing allo-HSCT. We systematically searched PubMed, Embase, the Cochrane Library, and CBM. Data were analyzed using RevMan5.4. Pooled hazard ratio (HR), standard mean difference (SMD) or odds ratio (OR) and corresponding 95% confidence interval (CI) are calculated for time-to-event data, continuous data, discontinuous data respectively. 17 eligible studies were included, involving 2169 patients main receiving haploidentical SCT (haplo-SCT) or umbilical cord blood transplantation (UCBT). Meta-analysis showed that DSAs-positive patients are associated with significantly higher risk of GF(OR = 12.87, 95%CI, 6.45-25.70; P < 0.00001; OR = 4.76, 95%CI, 2.88-7.87), poorer neutrophil engraftment (HR = 2.20, 95%CI, 1.02-4.73; P = 0.04; HR = 1.83, 95%CI, 1.46-2.30; P < 0.00001), worse OS (HR = 3.19, 95%CI, 1.85-5.50; P < 0.0001; HR = 1.68, 95%CI, 1.04-2.71; P = 0.03), and inferior PFS (HR = 4.25, 95%CI, 1.59-11.40; P = 0.004; HR = 4.83, 95%CI, 1.65-14.12; P = 0.004) in haplo-SCT and UCBT, respectively.