Chromium-51 release from human blood platelets by anti A antibody

Platelets were obtained by differential centrifugation from Group A donors and were incubated with Na2-51Cr04. After washing to remove excess chromium, the platelets were exposed for one hour to Anti A antibody which showed agglutinating activity only. Chromium release was no greater than that of controls. Hemolytic Anti A in the presence of rabbit complement released 15 percent more chromium than controls. Anti P1A1, a platelet specific antibody, when incubated with platelets in the presence of rabbit complement released 45 percent more chromium than controls. It appears that Anti A antibody is not as destructive to platelets as a platelet specific antibody is, even when the Anti A antibody shows hemolytic activity with red cells. These observations are in agreement with previous in vivo studies of ABO incompatible platelets.