IC-05. The major histocompatibility antigen mismatch pattern and its impact on the risk of acute GVHD in allogeneic hematopoietic stem cell transplantation from partially matched unrelated donors
Elmira I. Kolgaeva, Mikhail Yu. Drokov, Natalia N. Popova, Zoya V. Konova, Mobil I. Akhmedov, Feruza A. Omarova, Olga S. Starikova, Ulyana V. Maslikova, Ekaterina D. Mikhaltsova, Mariya V. Dovydenko, Olga M. Koroleva, Anna A. Dmitrova, Darya S. Dubnyak, Vera A. Vasilyeva, Larisa A. Kuzmina, Elena N. Parovichnikova, Valery G. Savchenko
National Research Center for Hematology, Moscow, Russia
Contact: Dr. Mikhail Yu. Drokov, e-mail: mdrokov@gmail.com
Summary
Introduction
Partially matched unrelated donors significantly expand the availability of allogeneic hematopoietic cell transplantation (allo-HSCT). However, the choice of donor is most often complicated by the availability of limited data on the tissue typing of the donor-recipient pair. Paczesny et al. has demonstrated that a mismatch for HLA-B locus in the patients increased the risk of severe graft-versus-host disease (GVHD) in unrelated allo-HSCT. Our aim was to demonstrate the impact of MHC-loci discordance upon the risk of developing acute GVHD in allo-HSCT from partially matched unrelated donors.
Materials and methods
We analyzed the results of 47 patients who underwent allo-HSCT from partially matched unrelated donor within the period from 2013 to 2020. The analysis included patients with mismatch in one MHC locus who had successfully engrafted and lived for 100 days and more. Patient characteristics are presented in Table 1. The patients had unrelated donors with mismatches for HLA-A (n=20, 43%), HLA-B (n=8, 17%), HLA-C (n=7, 15%), HLA-DR (n=10, 21%), and HLA-DQ locus (n=2, 4%). The probability of GVHD was estimated using Kaplan-Meier method, and inter-group comparisons were assessed using the log-rank test. A p<0.05 was considered significant.
Table 1. Characteristics of patients included in the study
Results
The results of our study are shown in Figure 1. HLA-A mismatch was associated with higher risk of developing GvHD, as compared with other loci mismatch (50% vs 22.2%, p=0.05). HLA-B mismatch was not linked with higher risk of GvHD as compared with other loci mismatch (37.5% vs 33.3% p=0.05). No other HLA-mismatch loci were linked with higher risk of GvHD.
Conclusions
The risk of acute GVHD in allo-HSCT from unrelated donors with HLA-A locus mismatch proved significantly higher, compared to mismatches for other loci, while differences at the HLA-B locus did not seem to have the same effect. Thus, in order to reduce the risk of GVHD, when choosing a partially matched unrelated donor, it is advisable to avoid candidates with HLA-A locus mismatch.
Keywords
HLA loci, hematopoietic cell transplantation, acute GVHD, unrelated donor.
