Immunoblot analyses of platelet P-selectin, CD63, and calpain. Samples of WPL and PRPL from patients (*), unaffected family members, healthy controls (C), the normal pool (NP), and an individual from the first family (F1) were separated using nonreduced SDS-PAGE and analyzed by immunoblotting with polyclonal anti–P-selectin, monoclonal anti-CD63, and monoclonal anticalpain. The arrow indicates degraded P-selectin. Intact calpain heavy chain migrated slightly higher than the reported 80-85 kD molecular weight25,37 38 in the 4% to 8%/15% gradient gels.