Serum procollagen type III peptide in chronic hepatitis B. Relationship to disease activity and response to interferon-alpha therapy.

The clinical significance of serum procollagen type III peptide, a marker of active fibrogenesis, was evaluated in 110 hepatitis B surface antigen positive patients with chronic hepatitis (32 chronic persistent hepatitis, 60 chronic active hepatitis, and 18 active cirrhosis), selected on the basis of active viral replication and biochemical activity, including 54 cases treated with interferon-alpha. At presentation the procollagen type III peptide level serum was above normal in 48 (44%) of the 110 patients and the median value was significantly higher than that of healthy carriers with normal transaminases and histology (P < 0.000005). Semiquantitative histological evaluation showed a significant correlation between serum procollagen type III peptide levels and necrosis/inflammation in the subgroup of patients with chronic active hepatitis, but no relationship with the score of fibrosis. Among patients treated with interferon-alpha and with increased fibrogenic activity (indicated by high pretreatment serum levels of procollagen type III peptide), peptide levels were significantly decreased when pretreatment levels were compared with those at 12 months after therapy withdrawal, both in responders to interferon (P = 0.022) and non-responders (P = 0.012). However, serum procollagen type III peptide levels normalized in 75% of responders to interferon with sustained serological and histological remission of liver disease, but in only 21% of non-responders (P = 0.02). These results obtained in a well-defined population suggest that serum procollagen type III peptide is a better marker of active fibrogenesis and inflammation than an indicator of the extent of fibrosis, and that interferon may reduce active liver fibrogenesis in chronic hepatitis B independently of its effect on viral replication. However, a consistent proportion (56%) of our chronic hepatitis B patients had normal serum procollagen type III peptide levels at presentation, thus precluding the clinical use of this marker both for diagnosis of liver injury and for monitoring the therapeutic response to interferon.