Alloimmunisation to HLA Antigens following Transfusion with Leucocyte‐Poor and Purified Platelet Suspensions

Abstract
24 previously non‐transfused patients were given three transfusions of 200 times 108 platelets at 14‐day intervals. Group I (12 patients) received leucocyte‐poor platelet suspensions with a mean contamination of 15 times 106 leucocytes per transfusion. Group II (12 patients) received platelets with 6 leucocytes per transfusion. 5 patients in group I and no patients in group II developed lymphocytotoxic antibodies (p == 0.037). Platelets with fewer than 5 times 106 leucocytes did not seem to stimulate a response to major histocompatibility antigens, but with a small contaminating dose of leucocytes appeared to be highly immunogenic.