Serum complement in chronic liver disease.

Total serum haemolytic complement activity (CH(50)) and the serum concentrations of both the third and fourth components of the complement system (C3 and C4) have been measured in 29 control subjects, 92 patients with chronic hepatocellular disease, and eight patients with large duct biliary tract obstruction. The mean C4 concentration was reduced in all types of chronic liver disease studied. However, the mean CH(50) and C3 values were increased in compensated primary biliary cirrhosis, were relatively normal in non-cirrhotic chronic active hepatitis, and were decreased in cryptogenic cirrhosis, particularly when ascites was present. There was a significant correlation between CH(50) and C3 in patients with chronic liver disease but no correlation between CH(50) and C4 or between C3 and C4. Raised values for CH(50) and C3 in primary biliary cirrhosis may be due at least in part to concomitant cholestasis since these values tend to be raised in patients with large duct biliary tract obstruction. Although primary biliary cirrhosis, chronic active hepatitis, and cryptogenic cirrhosis are considered to be part of a spectrum of chronic liver disease associated with disturbed immunity, the results of this study emphasize that there are clearly definable differences between these diseases in terms of the pattern of changes in serum complement.