Alloimmune platelet transfusion refractoriness circumvented by allogeneic stem cell transplantation

[Incidence and clinical significance of platelet transfusion refractoriness after allogeneic hematopoietic stem cell transplantation in patients with chronic myelomonocytic leukemia]

Objective: To retrospectively analyze the incidence and clinical significance of platelet transfusion refractoriness (PTR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with chronic myelomonocytic leukemia (CMML) . Methods: A cohort of 55 CMML patients received allo-HSCT at Peking University Institute of Hematology during 2004-2021 were retrospectively assessed. The incidence of PTR within 30 days after allo-HSCT was retrospectively analyzed, and the impact on clinical outcomes and bleeding event were compared between patients with platelet transfusion refractoriness (PTR) or effective platelet transfusion (EPT) . Results: The incidence of PTR after allo-HSCT in CMML patients was 25.5% (14/55) . PTR patients had a lower rate of platelet engraftment than EPT patients (28.6% vs 100%) , and the median time of engraftment was 67 (33-144) days and 21 (9-157) days respectively (P<0.010) . There was no significant difference between two groups in acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD) (P=0.183, P=0.455) . After following-up a median of 684 (24-3978) days, the 1-year overall survival (OS) and 1-year leukemia free survival (LFS) in PTR and EPT patients were (35.4±13.9) % vs (75.1±7.8) % (P=0.037) and (28.1±13.3) % vs (65.3±8.2) % (P=0.072) , respectively. The transplant-related mortality (TRM) were (48.2±2.4) % and (9.0±0.25) %, respectively (P=0.009) . Bleeding events occurred in five patients (35.7%) of PTR and 2 patients (4.9%) of EPT (P=0.009) . Conclusion: In CMML patients with allo-HSCT, the incidence of PTR is 25.5%, which was associated with delayed platelet engraftment, increased bleeding events, inferior OS and increased TRM.

Applicability of an instrument to identify human leukocyte antigen-compatible donors for platelet transfusions

Background

The selection of compatible human leukocyte antigen platelets has been associated with improved platelet increments. Therefore, an effective strategy would be the selection of donors who are genetically compatible according to the human leukocyte antigen system. Nonetheless, this is costly as it concerns a highly polymorphic system, which requires a large bank of genotyped donors.

Methods

This study evaluated the feasibility of virtual crossmatching using EpVix software, which simplifies the identification of compatible donors or donors with acceptable incompatibilities.

Results

Forty-three oncohematological patients were evaluated, in 96 platelet transfusion episodes with 16.3% of the patients being found to be refractory to platelet transfusions. Eight alloimmunized, multitransfused patients were selected to evaluate human leukocyte antigen compatibility against a bank of 336 platelet donors. At least partially compatible donors were found for all patients. The number of compatible donors was found to be inversely proportional to the human leukocyte antigen-panel reactive antibody score of each patient. It was noted that five patients with scores of 15% or less had at least 190 compatible donors; four fully compatible donors were found for two other patients with scores greater than 80% and only one patient (score of 93%) did not have a fully compatible donor. However, for this last patient, 40 donors were partially compatible according to the software.

Conclusion

The results showed the effectiveness of the use of the EpVix tool to identify potential platelet donors for multitransfused and/or alloimmunized patients, even with a small number of human leukocyte antigen genotyped donors available.