Changes in viremia and circulating interferon-α during hemodialysis in hepatitis C virus-positive patients: only coincidental phenomena?

Abstract

Background:It has been hypothesized that hemodialysis (HD) treatment per se can preserve patients from an aggressive course of hepatitis C virus (HCV) infection by reduction of viral load. The aim of the present study in HCV-positive (HCV+) HD patients is to determine whether HD induces the production of interferon-α (IFN-α) and if such production can contribute to viremia reduction. Methods:To address this issue, HCV RNA and IFN-α levels were determined in 11 HCV+ patients immediately before and at the end of a 4-hour dialysis session using cellulosic membranes and 24 and 48 hours later, ie, immediately before the subsequent dialysis session using the same membrane and at the end of the dialysis session. The same protocol was repeated 1 week later using a high-biocompatibility synthetic membrane. Results:HCV titer decreased in all patients after dialysis (range, 3% to 95%; P = 0.001) and thereafter progressively increased and returned to basal levels within 48 hours, with a new reduction during the next dialysis treatment. There was no significant difference in the magnitude of changes in HCV titers in tests performed using cellulosic or synthetic membranes. Plasma IFN-α levels increased markedly after dialysis using both cellulosic (in 9 of 11 cases) and synthetic membranes (in 10 of 11 cases; P < 0.01) and returned to basal levels within 48 hours; thereafter, IFN-α levels increased again during the next dialysis session. In some patients, plasma IFN-α levels after HD were approximately 50% of the level observed after therapeutic administration of 6 million units of IFN-α to 4 HD patients with chronic hepatitis. Conclusion:Although without a proven direct cause-effect relationship between HCV level reduction and induction of IFN-α after dialysis, our observation suggests an additional new mechanism for the unusually mild course of HCV infection in HD patients.