title: Complement activation in the adult respiratory distress syndrome following cardiopulmonary bypass.
abstract: We investigated complement fractions in patients after extracorporeal circulation for coronary bypass operations or cardiac valve replacement, and in two cases developing an adult respiratory distress syndrome (ARDS) after this type of intervention. The patients presenting an ARDS had significantly increased levels of C3d (p less than 0.001), the small molecular breakdown product of C3, associated with decreased levels of total classic haemolytic activity (p less than 0.05) and of the complement component C1q (p less than 0.001) when compared to a group of 10 patients who had uneventful evolution after bypass. However, all patients undergoing cardiopulmonary bypass had significantly increased levels of C3d (p less than 0.005 or less) associated with significant decrease of various complement components within 24 h after bypass, when compared to a control group of 5 patients investigated after aorto-iliac bypass graft surgery. We conclude that significant complement activation can persist in patients 24 h after bypass and--at higher levels--be a pathogenic and biological marker of ARDS after extracorporeal circulation.
mesh_terms: D000328:Adult; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003166:Complement Activating Enzymes / Q000378:metabolism; D003167:Complement Activation; D015922:Complement C1q; D003176:Complement C3 / Q000378:metabolism; D015933:Complement C3d; D003181:Complement C4 / Q000378:metabolism; D003165:Complement System Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000276:immunology*
chemical_list: D003176:Complement C3; D003181:Complement C4; D015922:Complement C1q; D015933:Complement C3d; D003165:Complement System Proteins; D003166:Complement Activating Enzymes