PLASMA-LEVELS OF IMMUNOSUPPRESSIVE MEDIATORS DURING CARDIOPULMONARY BYPASS

The aim of this study was to evaluate plasma levels of two mediators w ith immunosuppressive properties, complement fraction C3a (C3a) and tr ansforming growth factor-beta (TGF-beta 1), during extracorporeal circ ulation. The proliferation index after phytohaemagglutinin (PHA) stimu lation of isolated peripheral blood mononuclear cells was also investi gated Sixteen patients undergoing hypothermic (n = 8, group 1) and nor mothermic (n=8, group 2) cardiopulmonary bypass (CPB) were enrolled in this study. As a control, we evaluated four patients undergoing thora covascular operations without CPB. Blood samples were collected before CPB but after anaesthesia, every 30 min during CPB, at the end of CPB and 10 min after protamine administration Both C3a and TGF-beta 1 inc reased significantly during CPB and after protamine administration in the hypothermic as well as the normothermic group. In the latter case the increase of C3a and TGF-beta 1, although more prominent was not si gnificantly higher than in the former group. Conversely, the prolifera tion index of peripheral mononuclear cells had already decreased 30 mi n after CPB was started and remained depressed throughout the CPB time . These results suggest a possible role of C3a and TGF-beta 1 in the i mmunological changes occurring during extracorporeal circulation.