Background. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a definitive therapy for patients with different oncological and hematological diseases. The study of red cell chimerism is a crucial process for diagnosing transplant engraftment and functioning during the post-transplantation period.
Aim. To assess the effect of immunohematological (АВО and HLA donor–recipient matching) and medical (conditioning regimens) parameters on the onset time of post-transplantation donor chimerism which is determined by RBC antigens.
Materials & Methods. The study enrolled 54 patients at the Kirov Research Institute of Hematology and Transfusiology in Russia (25 female and 29 male patients) aged 3–60 years (median 32 years). All of them received allo-HSCT in 2013–2021. Acute leukemias were identified in 39 patients, 8 patients were reported to have malignant lymphoproliferative diseases, 3 patients had myeloproliferative neoplasms, and 4 patients were diagnosed with aplastic anemia. RBC antigens of donors and recipients were analyzed by gel hemagglutination using Bio-Rad (USA) reagents and equipment.
Results. The onset time of donor chimerism depends neither on the degree of HLA donor–recipient matching, nor on conditioning regimen. Donor chimerism in recipients with major ABO-incompatibility occurs significantly later than in patients with minor АВО-incompatibility and ABO-identity.
Conclusion. Monitoring of post-transplantation donor chimerism is an important diagnostic and prognostic tool to assess donor hematopoietic cell engraftment, hematologic recovery, graft rejection, and relapse of the disease. After allo-HSCT, first donor red cells occur in pairs with major АВО-incompatibility later than in pairs with minor АВО-incompatibility or ABO antigen compatibility. Other immunohematological and medical parameters do not affect the development rate of donor chimerism determined by RBC antigens.