The Specificity of Leukocyte and Platelet Alloantibodies in Sera of Patients with Nonhemolytic Transfusion Reactions

. To evaluate the relevance of HL‐A‐specific antibodies in nonhemolytic transfusion reactions, sera from 72 patients with transfusion reactions were examined using platelet microcomplement fixation and microlymphocytotoxicity. Lymphocytotoxic antibodies were found in 24 and platelet complement‐fixing antibodies in 18 patients. Thirteen positive sera were studied by absorption and elution with platelets. A total of 103 eluates (mean 7.9 eluates per serum) was tested serologically for antibody specificity. Results were statistically analyzed for χ 2 ‐association with known HL‐A antigens. All sera investigated contained HL‐A‐specific antibodies. Antibody specificities determined were directed against 7 antigens (1, 2, 3, 9, 10, 11 and W28) of the first series and 10 antigens (5, 7, 8, 12, W5, W10, W15, VV17, W21 and W27) of the second series of the HL‐A system. By means of antibody concentration in the eluates, all sera revealed cross‐reacting HL‐A‐specific antibodies. The clinical importance of buffy coat‐free red blood cells for the prevention of transfusion reactions is stressed.