Analysis of hepatitis C viral quasispecies in liver transplantation

The hepatitis C virus (HCV) is an RNA virus that replicates with a high rate of mutation, especially in the hypervariable region 1 (HVR-1). Continuous viral mutations lead to a mixed and changing populations of mutants, called quasispecies. The nature of the HCV quasispecies may have implications for viral persistence and pathogenies. Studies with liver transplant patients suggest a relationship between the degree of immunosuppression and the complexity of the quasispecies. This study evaluated whether immunosuppressive therapy modifies the evolution of HCV quasispecies among liver transplant recipients compared with immunocompetent HCV patients. Two groups were studied: 11 patients who underwent OLT for HCV-related cirrhosis and 10 control group patients. Two serum samples from each patient were obtained to analyze the HCV HVR1 region by RT-PCR. SSCP analysis failed to show statistically significant differences in the number of quasispecies at basal and final time points or at pretransplant versus posttransplant (7.3+/-2 vs 6.7+/-3 in control patients, respectively, and 4.4+/-2 vs 4.1+/-1 in transplanted patients, respectively). No significant difference was observed between missing or new variants in the control (2.8+/-2 vs 2.3+/-2, respectively) or transplanted group (2.5+/-2 vs 2.2+/-1, respectively). Upon sequence analysis, the genetic complexity was significantly lower among samples after OLT in transplanted patients (0.057+/-0.04 [pretransplant] vs 0.035+/-0.02 [posttransplant]; P=.048). However, no significant differences were found among control patients in basal versus final samples (0.04+/-0.03 vs 0.066+/-0.04, respectively). Our findings seem to demonstrate that viral quasispecies diversity is lower among patients receiving a liver transplant.