The patient's platelets show a much-decreased reactivity with convulxin. (A) The patient's platelets failed to react with 0.4 nM Cvx, whereas maximal aggregation was seen for control platelets. Only with much-increased amounts was a small residual aggregation seen for the patient. (B) Kinetics of the binding of FITC-Cvx to platelets as evaluated by flow cytometry. The histograms represent MFI values and show that increases were seen during a 30-minute incubation for the control, whereas for the patient the values remain close to baseline for even up to an hour.