Inhibition of platelet aggregation by cationic protein from polymorphonuclear leukocytes.

The cationic protein isolated from the granules of neutrophilic polymorphonuclear leukocytes inhibited the aggregation of human platelets as induced by collagen, thrombin, ristocetin, aggregated IgG by approximately 50% and anti-C1q by 75% but had no effect on aggregation-induced by ADP.