Cardiopulmonary bypass-induced complement activation. Evidence for C5a participation.

Plasma activity inducing polymorphonuclear neutrophils (PMN) aggregation, augmenting PMN adherence, plasma chemotactic activity as well as peripheral PMN count were estimated in patients during cardiopulmonary bypass. In the course of the surgical procedure the chemotactic activity and the activity inducing PMN aggregation were detected in plasma. The top of these two activities was always followed by the significant fall of the peripheral PMN count. The increase of the activity augmenting PMN adherence was observed in a part of cases, but when noticed, always preceded the maximum of the remaining evaluated activities.