Abstract

Serum C₃ (β_1C/β_1A) has been measured in normal individuals and the range found is in agreement with findings of other authors (85-370 mg/100 ml). In 18 patients with acute hepatitis and massive necrosis serum C₃ was consistently reduced to below 50% of normal. In other patients with acute hepatitis the serum C₃ concentration was normal. In the majority of the 150 patients with chronic liver disease serum C₃ concentration was normal. However, 10 patients (six with active chronic hepatitis, four with cryptogenic cirrhosis) had hypocomplementaemia. The reason for the depression is not clear but could reflect either decreased synthesis or increased consumption, or a combination of the two.