Accumulation of anaphylatoxins and terminal complement complexes in inflammatory fluids

The presence of anaphylatoxins (C3a and C5a) and terminal complement complexes (TCC) in different inflammatory fluids and plasma was studied in 33 patients. Anaphylatoxins were assayed using a radioimmunoassay technique, and the terminal complement complexes were determined by an ELISA method. Patients with peritoneal (n = 14), pleural (n = 7), pericardial (n = 6) or burn bullae fluid (n = 6) were studied. High C3a and TCC concentrations were found in all these fluids. Elevated C3a and TCC concentrations in inflammatory fluids were found not only in patients with elevated plasma C3a and TCC concentrations, but also in patients with normal plasma levels. No increases in C5a concentration were observed in pleural or burn bullae fluid. In one patient with pericarditis, and in subjects with acute pancreatitis with ascites, high C5a levels were found in the fluid. However, the high TCC concentration in the fluids suggests that C5a had been formed but was probably removed by leucocytes present in the fluid.