Changes in hepatitis C virus RNA viremia concentrations int long-term renal transplant patients after introduction of mycophenolate mofetil

Background. Mycophenolate mofetil (MMF) is a potent immunosuppressive agent and might inhibit chronic rejection, at least in primates. The prevalence of chronic hepatitis C virus (HCV) infection is high in renal transplant (R T) patients. To date, it has not been demonstrated whether MMF has any effe ct upon HCV viremia, Methods. Fourteen long-term HCV(S) RT patients with chronic allograft dysfu nction whose maintenance immunosuppression was based on cyclosporine, were given MMF therapy either in place of azathioprine (n=11) or in addition to baseline therapy (n=3), HCV viremia levels were measured by the Amplicor HC V-Monitor RT-PCR assay (Roche Diagnostic Systems) on two separate occasions before the introduction of MMF, and 1 year after changing to MMF or at the last follow-up visit. Results. MMF therapy was associated wi:th a significant rise in HCV viremia , i.e., 5.8+/-0.5 vs. 5.2+/-0.7 log copies/ml (P=0.01), although there were no significant changes in liver enzymes, The increase in HCV viremia was n ot related to HCV genotypes either. At the patient level, HCV RNA concentra tions changed in only seven patients (group B), i.e. >1 log copies/ml, wher eas it remained stable in the others (group A). Before conversion, the only significant difference between group A and. B was the level of HCV RNA, i. e., 5.5+/-0.4 log copies/ml in group A and 4.9+/-0.7 log copies/ml in group B (P=0.05). Conclusion. Our study suggests that MMP should be used with caution in stab le HCV RT patients whose maintenance immunosuppressive therapy is based on cyclosporine, at least in the case of patients with a low HCV RNA titer.