Interferon-alpha therapy has a beneficial effect. in 30-40% of selected patients with chronic hepatitis B who respond by clearing hepatitis B e antigen (HBeAg) and hepatitis B viral (HBV) DNA from serum. This is usually associated with normalization of serum aminotransferase activities. On long-term follow-up of treated patients, it is apparent that many go on to clear hepatitis B surface antigen (HBsAg) from serum with considerable improvement in liver histopathology. Among patients with clinically apparent chronic HBV infection such as those with decompensated cirrhosis or the nephrotic syndrome, a serologic response is usually followed by slow but steady clinical and biochemical improvement. However, even among patients who have cleared HBsAg from serum, HBV-DNA remains detectable within the liver and may provide a source of reactivation in rare patients in association with immunosuppression. (C) Journal of Hepatology.