AET-treated platelets: their usefulness for platelet antibody detection and an examination of their altered sensitivity to immune lysis.

2-Aminoethylisothiouronium bromide (AET) increases the sensitivity of blood cells to complement-mediated immune lysis. We compared the sensitivities of untreated or AET-treated platelets to immune lysis induced by different types of platelet antibody in the 51Cr platelet lysis test. AET platelets were 8-16 times more sensitive to autoantibody and alloantibody, but 8-16 times less sensitive to drug-dependent antibody. AET-platelets bound similar amounts of alloantibody but less drug-dependent antibody, and they lysed at higher complement dilutions than did untreated platelets. AET-platelets detected 10 of 25 autoantibodies, 9 of 9 alloantibodies, and 5 of 8 drug-dependent antibodies. Untreated platelets detected 1 of 25, 6 of 9, and 7 of 8 of these respective platelet antibodies. The use of AET-platelets in the 51Cr platelet lysis test increases its sensitivity for detecting non-drug-dependent platelet antibodies. AET-platelets resemble paroxysmal nocturnal hemoglobinuria (PNH) platelets in their enhanced sensitivity to complement-mediated lysis. They differ from PNH platelets in their insensitivity to immune lysis induced by drug-dependent antibodies and, in this respect, are similar to Bernard-Soulier syndrome platelets.