Prediction of sustained response to interferon alpha therapy with serum soluble interleukin 2 receptor levels in patients with chronic hepatitis C

Abstract

It is difficult to predict sustained response to interferon alpha therapy for patients with chronic hepatitis C. Loss of serum hepatitis C viral RNA (HCV-RNA) and normal serum alanine aminotransferase (ALT) level at the end of treatment do not necessarily mean sustained response. Relapses are very common. In this study, serum levels of soluble interleukin 2 receptor (sIL-2R, an indicator of immune response) were investigated to see if they are helpful to predict sustained response. We studied consecutive twenty patients with chronic hepatitis C who had HCV-RNA negativity and normal ALT levels at the end of interferon alpha therapy. Total doses of interferon ranged from 288 million units (MU) to 480MU. Serum HCV-RNA sequences were examined before and at the end of treatment by nested polymerase chain reaction (PCR) using primers to the 5′ noncoding region. Serum sIL-2R levels were also measured before and at the end of treatment using enzyme-linked immunoassay. Eight of twenty (40%) patients were sustained responders and the rest of the patients (60%) relapsed (partial responders). Serum sIL-2R levels in sustained responders decreased (−96.2 ± 45.2 IU/l), whereas partial responders showed increase in serum sIL-2R levels (81.3 ± 50.5 IU/l). The difference in sIL-2R changes between sustained responders and partial responders was significant ( P < 0.01). In particular, six of six (100%) patients who showed more than 50 IU/l increase in sIL-2R levels were partial responders. In conclusion, monitoring serum sIL-2R levels with HCV-RNA and ALT is useful to predict sustained response to interferon.