Clinical relevance of anti-interferon antibodies in the serum of chronic hepatitis C patients treated with interferon-alpha

The development of anti-interferon (anti-HFN) antibodies in the serum of patients undergoing antiviral therapy has been postulated as one possible cause of interpatient variability in response to therapy. We analyzed the relationship between the appearance of anti-IFN antibodies and the loss of response to interferon-alpha (IFN-alpha), as characterized by a breakthrough of serum aminotransferase after a period of complete biochemical remission. The analysis involved clinical trials where neutralizing anti-IFN antibodies were detected by standardized and comparable methods, The results show that a time relationship between breakthrough and anti-IFN antibodies is observed in only a few cases and is independent of the type of IFN-alpha preparation used. Thus, causes of IFN resistance other than anti-IFN antibodies must also be implicated in most breakthrough cases. Another potential is the selection of drug-resistant viral strains, Current rational behavior following the appearance of breakthrough (from whatever cause) in clinical practice advocates changing treatment to a different type of IFN-alpha. The detection of anti-IFN enzyme-linked immunosorbent assay (ELISA) antibodies or IFN neutralizing antibodies does not appear to provide any additional information for decision making.