P1387: MONITORING OF DONOR CHIMERISM ON RED BLOOD CELLS ANTIGENS AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION

Abstract

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for diseases of the blood system. One of the indicators reflecting the functioning of donor hematopoietic tissue is posttransplant chimerism. Aims: To evaluate the effect of ABO belonging of the donor and recipient on the timing of the formation of red blood cells (RBS) donor chimerism after HSCT. Methods: The study included 57 patients who underwent HSCT in 2013-2021. Patient age ranged from 3 to 60 years (median - 34). Diagnosis of the patients: acute leukemia - 42 persons, Hodgkin’s lymphoma - 6, aplastic anemia - 4 and other blood diseases - 5. Before HSCT, the study of RBC antigens of the ABO, Rh, Kell systems in donors and recipients was performed by gel agglutination using reagents and equipment BioRad (USA). Antigens identified in the recipient’s phenotype and absent in the donor’s phenotype were considered informative, or vice versa. For statistical data processing, the nonparametric Kruskal-Wallis test was used. Results: Thirty-two (56.1%) of 57 pairs differed in ABO system antigens. Of these, 16 pairs (28.1%) had a major ABO incompatibility, 16 pairs (28.1%) had a minor incompatibility. The time of appearance of donor’s RBS in patients with ABO incompatibility had a wider range (from 14 to 201 days) and occurred significantly later (Me - 28 days) than in recipients ABO identical with donors (Me - 20 days), and from minor ABO incompatibility (Me - 19 days) (Table 1). The periods of occurrence of 50% and 100% donor chimerism did not differ significantly in all groups. In the group of recipients with major ABO incompatibility a case of pure red cell aplasia was revealed. The first appearance of RBC carrying donor antigens was recorded on day 201. 100% donor chimerism was formed on day 278. Antibodies of the ABO system (anti-A) IgG were present in the recipient’s blood for 189 days, IgM - for 230 days. Table 1. - The emergence of chimerism depending on ABO compatibility of donor-recipient pairs ABO identical Minor ABO incompatibility Major ABO incompatibility р (n=25) (n=16) (n=16) First appearance of donor chimerism 20 (12-54) 19 (11-41) 28 (14-201) р<0.05 Ме (Min-Max days) 50% donor chimerism 41 (19-142) 41 (26-74) 54 (34-227) p>0.05 Ме (Min-Max days) 100% donor chimerism 138 (40-316) 110 (70-150) 141 (90-278) p>0.05 Ме (Min-Max days) Summary/Conclusion: In recipients with a major ABO incompatibility the first appearance of donor’s RBS after HSCT occurs significantly later than in couples ABO identical and couples with a minor ABO incompatibility.