Comparative analysis of immunogenetic characteristics of potential hematopoietic stem cell donors from the registries of two Russian megapolises

Abstract

Efficacy of search for the unrelated compatible transplant donors depends on a number of factors. Of most importance are the standards of primary HLA typing, and the immunogenetic diversity of the donor pool. Timely donor selection guarantees the optimal timing for stem cell transplantation. This factor exerts positive influence upon the transplantation outcomes. In 2019, The Bone Marrow Donors Registry at the Russian Research Institute of Haematology and Transfusiology has implemented HLA-typing for HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQB1 genes as a standard for primary immunogenetic examination, in order to reduce the donor search period. The aim of our study was to evaluate the HLA typing results for potential stem cell donors at our Registry as compared with immunogenetic profile of donors at the Registries arranged in two Russian megapolises. All currently known groups of HLA-C, HLA-DRB1, HLA-DQB1 gene alleles, 19 of 21 open groups of HLA-A gene alleles, 34 of 36 known groups of HLA-B gene alleles were screened in the donors from our Registry. The most common HLA alleles groups were as follows: A*02 (0.2957), A*03 (0.1432), A*01 (0.1155), A*24 (0.1128); B*07 (0.1282), B*35 (0.1084), B*44 (0.0921), B*18 (0.0745); C*07 (0.2738), C*04 (0.1361), C*12 (0.1202), C*03 (0.1134), C*06 (0.1127); DRB1*15 (0.1445), DRB1*07 (0.1420), DRB1*13 (0.1271), DRB1*01 (0.1269), DRB1*11 (0.1216); DQB1*03 (0.3517), DQB1*06 (0.2269). A total of 1702 HLA-A*-B*-C*-DRB1*-DQB1*-haplotypes were revealed in our donor pool. The frequency of nine HLA-haplotypes exceeded 0.01: A*01-B*08-C*07-DRB1*03-DQB1*02 (0.0366), A*03-B*07-C*07-DRB1*15-DQB1*06 (0.0269), A*03-B*35-C*04-DRB1*01-DQB1*05 (0.0238), A*02-B*13-C*06-DRB1*07-DQB1*02 (0.0204), A*02-B*07-C*07-DRB1*15-DQB1*06 (0.0184), A*25-B*18-C*12-DRB1*15-DQB1*06 (0.0127), A*02-B*18-C*07-DRB1*11-DQB1*03 (0.0126), A*02-B*15-C*03-DRB1*04-DQB1*03 (0.0123), A*02-B*41-C*17-DRB1*13-DQB1*03 (0.0109). We carried out a comparative analysis of the HLA-haplotypes distribution for the donors of three Russian registers: Russian Research Institute of Haematology and Transfusiology (St. Petersburg); First St. Petersburg State I. Pavlov Medical University (St. Petersburg); National Medical Research Center for Hematology (Moscow). The six most common HLA-haplotypes among the donors from three Russian registers had the same rank positions and frequencies. The differences of some less common HLA-haplotypes distribution were determined. The results of our study indicate the immunogenetic diversity of the donor pool the Registry of Russian Research Institute of Haematology and Transfusiology. This fact, along with usage of international standards for primary immunogenetic examination is a prerequisite for effective donor search for the patients requiring stem cell transplantation.