HLA-A, B antigens and the ABO group were examined in 184 patients with aplasia of bone marrow and leukaemia and in 373 of their relatives, mostly siblings. A HLA-A, B donor, identical or compatible, was found for 35.87% patients, a HLA-DR identical for 84.21% of 38 patients who had a HLA-A, B identical relative. Bone marrow was transplanted to 16 patients (10 with bone marrow aplasia, 6 with acute or chronic leukaemia), with one exception bone marrow from a sibling. The bone marrow was accepted in all patients but two where the transplantation was made despite MLC positivity. From the results ensues that it is essential for successful transplantation of bone marrow to ensure maximal identity between donor and recipient as regards the ABO group, HLA antigens and negativity of the MLC reaction. The negativity of the MLC reaction is more important than HLA-DR identity; when assessing only one HLA-DR antigen in a donor identical with the patient, it cannot be ruled out that on the lymphocytes of the donor there exists another one which was not detected. The authors discuss the causes of different results of the MLC reaction and HLA-A, B, DR typing.

Keywords: ABO Blood-Group System /immunology/; Bone Marrow Transplantation /immunology/; Female; HLA Antigens /analysis/; Humans; Lymphocyte Culture Test, Mixed; Male; Tissue Donors