Effect of prostacyclin (PGI2) on immune-complex-induced neutropenia.

This study reports the results of in vitro and in vivo investigations on the effect of prostacyclin (PGI2) on polymorphonuclear neutrophils (PMN) challenged with immune complexes (IC). In vitro, PGI2 does not affect the interaction of IC with PMN membrane receptors, but prevents the ensuing PMN aggregation and secretion of platelet-activating factor, a lipid mediator responsible for immune-induced PMN aggregation. In vivo, the infusion of PGI2 in New Zealand white rabbits injected with IC prevents IC-induced neutropenia and thrombocytopenia as well as the embolization of PMN into the pulmonary peripheral capillary network. These results suggest a physiological role for PGI2 in modulating the interaction between IC and PMN.