Managing patients on interferon therapy.

Abstract

Interferon (IFN) has become the standard therapy for chronic hepatitis C. The use of IFN should be accompanied by adequate diagnosis and management using standard practices as well as new and sophisticated techniques now available. A liver biopsy performed prior to IFN therapy initiation remains the standard for adequate histological diagnosis of HCV disease as well as determination of disease severity and the presence of liver cirrhosis. ALT normalization is not adequate to determine complete short-term response to IFN treatment. Adverse effects resulting from IFN therapy include a flulike syndrome, hematologic effects, neuropsychiatric effects, and thyroid abnormalities. The majority of these can be adequately managed without discontinuation of IFN treatment. However, preexisting psychiatric conditions are a contraindication to IFN therapy. IFN treatment also is contraindicated in patients with autoimmune hepatitis (AIH). Therefore, it is important to distinguish AIH from chronic HCV infection using HCV-RNA analysis and determination of autoimmune titers (including anti-LKM antibodies, anti-SMA, and ANA). Recently reported adverse effects of IFN include respiratory and ocular effects. Serological diagnosis of HCV infection has evolved to the use of second- and third-generation ELISA tests. Although sophisticated, these tests cannot distinguish between active and quiescent infection, and therefore are of limited value in monitoring treatment response. Several other techniques have been suggested: the ratio between IgG and IgM class anti-HCV core antibodies, detection of antibodies against a glycosylated recombinant product of the E2 envelope glycoprotein, and several different polymerase chain reaction (PCR) techniques. The latter appears to be the most promising. Use of these techniques should be incorporated into the monitoring of IFN therapy to assist in the evaluation of adequate treatment response, the need for treatment alteration, and estimation of relapse risk upon treatment cessation.