Comparative study of clinical, histological, and immunological responses to interferon therapy in type non-A, non-B, and type B chronic hepatitis.

Nineteen patients with chronic non-A, non-B hepatitis (CH-NANB) and 24 patients with chronic hepatitis B (CH-B) were treated with interferons, and the therapeutic and biological responses of the two groups (CH-NANB and CH-B) were compared. All patients had had sustained elevations in serum glutamic pyruvic transaminase (sGPT) levels for more than 6 months and were proven to have chronic hepatitis by liver biopsy. alpha-Interferon (IFN-alpha) or beta-interferon (IFN-beta) was administered in low doses of 3 to 6 mega international units (MIU) daily for 4 wk. Liver biopsies were taken from 13 CH-NANB and 14 CH-B subjects just before and immediately after treatment, and histological findings were assessed by the histology activity index (HAI) score. SGPT levels decreased much more rapidly and markedly in CH-NANB than in CH-B during IFN therapy (p less than 0.01). The HAI score decreased 3.5 points in CH-NANB and 1.0 point in CH-B between pretreatment and posttreatment. Serum beta 2-microglobulin (beta 2-MG) increased in both types of chronic hepatitis during treatment, but the rate of elevation was significantly less in CH-NANB than in CH-B (p less than 0.001). beta 2-MG expression on hepatocytes stained by the PAP method was almost identical in CH-NANB before and after treatment, whereas it increased steadily in CH-B. The serum 2',5'-oligoadenylate synthetase level increased in both types of hepatitis on IFN administration. These results suggest that, in IFN treatment for CH-NANB, the antiviral actions of IFNs may play a very important role in reducing the activity of chronic hepatitis.