Class I HLA antigens hepatic display and beta-2-microglobulin serum values in chronic hepatitis C: effect of treatment with recombinant alpha interferon.

BACKGROUND/AIMS: Enhanced hepatocellular display of class I HLA antigens together with rising serum beta-2-microglobulin (a subunit of class I HLA molecule) and transaminases is reported in patients with chronic hepatitis B during treatment with interferon as an index of immune lysis of virus infected cells.

METHODOLOGY: We studied class I HLA antigens and beta-2-microglobulin display in the livers of 23 patients with chronic hepatitis C before and after a 12 month treatment with recombinant alpha interferon. Beta-2-microglobulin serum values were monitored. In all the patients before treatment, class I HLA antigens and beta-2-microglobulin were diffusely displayed in the bile duct epithelium, in the sinusoidal lining cells, in approximately 50% of the inflammatory cells and in the hepatocyte membrane with marked staining in the areas of periportal and lobular necrosis.

RESULTS

At the end of the treatment, class I HLA antigens and beta-2-microglobulin were no longer or only faintly detectable in the hepatocytes of 12 patients who showed clinical and histological improvement. The immunohistochemical pattern was unchanged in the 11 patients who did not respond to the therapy. Baseline serum beta-2-microglobulin values were high in all the patients and decreased significantly only in the group of responders. No peaks of transaminases were registered.

CONCLUSIONS

The disappearance or reduction of HLA hepatocellular display without acute increase of serum beta-2-microglobulin values and transaminases during successful treatment with interferon in chronic hepatitis C suggests a clearance of the virus due to direct antiviral rather than immunologically mediated mechanism.