Serum type III procollagen peptide concentrations in severe chronic active hepatitis: Relationship to cirrhosis and disease activity

To analyze the correlations between the presence of cirrhosis and hepatocellular inflammation and the serum concentrations of the amino‐terminal peptide of procollagen type III in chronic liver disease, we measured procollagen type III concentrations in paired serum samples from 46 patients (17 had cirrhosis) with severe chronic active hepatitis during a therapeutic treatment trial. Coded sera were analyzed for procollagen type III concentrations using both a standard and a recently described Fab radioimmunoassay to compare their relative diagnostic accuracy. Mean procollagen type III levels were elevated to the same extent in the cirrhotic and noncirrhotic groups at entry into the study. In response to immunosuppressive therapy, the initially elevated procollagen type III levels improved to normal values at remission in both groups. Qualitatively, the results were similar using either assay, but the standard assay was more sensitive for identifying the clinical stage of disease (i.e., active disease vs. disease in remission) than the Fab assay. Since both procollagen type III levels and standard liver function tests correlated well individually with the presence or absence of active disease, they also correlated with each other when both entry and remission values were considered. However, procollagen type III levels correlated poorly with indicators of inflammation (histologic grade and serum transaminase levels) during active disease. It is concluded that procollagen type III levels change in concert with standard liver function tests but do not quantitatively reflect inflammation or static measurements of hepatic fibrosis in severe chronic active hepatitis. However, these preliminary results suggest that procollagen type III can distinguish active disease from chronic active hepatitis in remission. Consequently, this test may be useful for monitoring disease activity and therapeutic response in severe chronic active hepatitis. For this purpose, the standard procollagen type III radioimmunoassay has greater diagnostic accuracy than the Fab radioimmunoassay.