Leukocyte Effects of C5a-Receptor Blockade During Simulated Extracorporeal Circulation

C5a receptor blockade during simulated extracorporeal circulation completely blocked neutrophil β2 integrin upregulation and induction of plasma interleukin 8, suggesting an acute downregulatory effect on neutrophil chemotaxis-related pathways, while preserving terminal complement generation and neutrophil elastase release. Inhibition of leukocyte-platelet conjugate formation suggests a novel function for leukocyte adhesive receptors, possibly related to preservation of elastase generation.