Interferon-alpha induces remission in 30% to 40% of patients with chronic hepatitis B, but its effect on hepatic connective tissue turnover has not been well documented. We studied the changes in serum procollagen III propeptide and laminin-P1 peptide (Lam-P1) in 33 patients with chronic hepatitis B (11 nontreated controls and 22 treated patients) during a 4-mo randomized trial of interferon-alpha. Liver biopsy specimens were obtained at the start of treatment and 12 mo later. Liver biochemical tests, procollagen III propeptide, laminin-P1 peptide and hepatitis B virus DNA polymerase were determined before treatment with interferon was begun (mo -3), at the initiation (0 time) and completion of treatment (mo 4) and also at 8, 12 and 18 mo. Treated patients were classified as "responders" and "nonresponders" on the basis of clearance of HBV e antigen from serum. There were no significant changes in the control group, whereas the responders had persistent decreases in ALT, AST, hepatitis B virus dna polymerase, procollagen III propeptide and laminin-P1 peptide. The nonresponders had transient ALT, AST and hepatitis B virus dna polymerase reductions that returned toward baseline levels during follow-up, but procollagen III propeptide and laminin-P1 peptide persisted below the baseline at mo 18. Significant correlations between procollagen III propeptide and laminin-P1 peptide with ALT, AST and liver histologic specimens were noted at baseline but not after 12 mo. Changes in procollagen III propeptide levels also correlated with changes in AST, ALT and liver histologic specimens.(ABSTRACT TRUNCATED AT 250 WORDS)