OD-01. Increasing the HLA phenotypes diversity of potential hematopoietic stem cells donors
Alena V. Hlaz, Anatoly L. Uss
Minsk Scientific and Practical Center for Surgery, Transplantology and Hematology, Minsk, Republic of Belarus
Dr. Alena V. Hlaz, e-mail: email@example.com
Recruitment of donors with unique HLA phenotypes increases an overall antigenic diversity of hematopoietic stem cell (HSC) donor pool and thus may increase the likelihood of donor detection for patients with rare phenotypes. According to the World Association of Bone Marrow Donors, no more than 11 unique phenotypes per thousand new donors were added to donor database in 2020. An increase in the antigenic diversity of potential HSC donors makes it possible to select optimal donors for patients with rare HLA phenotypes. There is currently no generally accepted strategy for attracting potential HSC donors. Some donor centers perform typing among small ethnic groups in order to increase the number of rare phenotypes and recruit donors with unique or rare HLA antigens. In addition, donor centers or registries can analyze regional differences in phenotype frequencies and selectively recruit donors from specific regions. Attracting related donors with rare antigens may be optimal with regard to efficiency.
Summarized analysis of the donor database from the HSC Registry of the Republic of Belarus are presented in Table 1. The frequency of phenotypes with rare antigens in Grodno was lower than in other regions (p <0.05). In Mogilev, the frequency of occurrence is higher than in Vitebsk, Gomel and Grodno (p <0.05). The distribution of rare and frequent antigens among men and women, adjusted by region, is homogeneous (Breslow-Day test of homogeneity of the odds ratio p=0.452) and indistinguishable: the Cochran-Mantel-Haenszel estimate (CMH method) is 1.05 (95% CI 0, 97-1.12), p=0.215.
Hence, a strategy for attracting potential donors to the registry can be represented by the following algorithm:
• inclusion of related donors with “rare” antigens in the phenotype, regardless of age;
• attracting potential donors with “rare” antigens in the phenotype, regardless of gender, taking into account the frequency of occurrence of “rare” antigens under the age of 50;
• recruiting young men under the age of 40 without taking into account the likelihood of detecting rare antigens in the phenotype.
Donor, phenotype, registry, Belarus.
Table 1. The distribution of phenotypes by region, taking into account the number of rare antigens