HL-A antigens in serum from bone marrow harvested for diagnostic purposes

Tissue typing employing the lymphocytotoxicity micro-assay was performed by introducing in the system approximately 15% of autologous or homologous ultra-centrifuged blood serum, both of peripheral and bone marrow source. As a rule, the pattern of reactivity was unaffected by peripheral blood serum, whereas the cytotoxicity was nearly always inhibited by autologous bone marrow blood serum or by homologous one from donors sharing the inhibited HL-A specificities with the donors of lymphocytes. These results suggest that at least in these patients HL-A antigens are present in bone marrow blood serum at a concentration which is definitely higher than in peripheral blood.