Inhibition of the Response in Mixed Leukocyte Cultures by Alloimmune Plasma

Summary: Plasma containing known alloantibodies from 2 multiply transfused patients with aplastic anemia was added to mixed leukocyte culture cell suspensions. The plasma inhibited the response of the patient's own cells and those of their. HL-A-compatible sibling's cells to allogeneic cells from family members. The response to phytohemagglutinin and to lymphocytes from an unrelated donor was not abolished. This gave a false impression of mixed leukocyte culture histocompatibility. When nonimmune plasma was substituted for the patient's plasma, the lymphocytes reacted in a pattern that would be predicted fromHL-A serotyping and platelet survival between donorrecipient pairs. It is concluded that alloimmune human plasma must be eliminated from mixed leukocyte cultures before results can be properly interpreted.