Reactions of 9 patient antibodies (left) and 13 antibodies from healthy subjects (right) against platelets saturated with monoclonal antibodies 7E3 and AP3.

Values shown are the ratios of MFI obtained with 7E3-coated platelets to that obtained with AP3-coated platelets (7E3:AP3). Reactions of the patient antibodies against 7E3-coated platelets were significantly stronger (up to 100 times) than those obtained with AP3-coated platelets (P < .001). In contrast, antibodies from the healthy subjects failed to discriminate between the 2 preparations. Similar results were obtained when monoclonal AP2 was substituted for AP3 (data not shown). Brackets depict mean ± 1 SD.