Flow cytometric analysis of GPIIb-IIIa content in platelets from the proband, her parents, and her brother. The fluorescence analysis was performed in a Coulter cytometer, model Epics XL. Results are expressed as semilog plots of cell number versus fluorescence intensity. The upper panel shows the fluorescence signals of GPIIIa and GPIIb from control platelets. The negative control represents the fluorescent signal of platelets without antibodies. The middle panel shows the labeling of GPIIIa with the MoAb P95.2 in platelets from the proband, her parents, and her brother. The lower panel shows the results of labeling GPIIb with the MoAb M3 in platelets from the proband, her parents, and her brother. For the sake of clarity, the original plots have been redrawn.