Increased level of the complement C3 protein in endogenous hypertriglyceridemia.

When compared to values obtained in normalweight, normolipidemic control subjects, the level of complement C3 protein and total complement activity (CH50) were found to be obviously decreased in patients with decompensated cirrhosis of the liver and slightly but significantly increased in subjects with type IIb and type IV hyperlipoproteinemia. C3 protein level was positively correlated with the concentration of serum cholesterol, the logarithm of serum triglyceride concentration, serum pseudocholinesterase and total complement activity. There were no significant differences concerning C3 protein level between hyperlipidemic subjects with clinical atherosclerosis and those without documented vascular disease. It is suggested that accelerated lipoprotein turnover occurring in many subjects with type IIb and type IV hyperlipoproteinemia might enhance the synthesis of several liver produced plasma enzymes and proteins including the C3 protein of the complement system.