Abstract: Objective To investigate the association between the differentiations of CD8⁺ T cell before treatment and the rapid virological response to antiviral therapy in patients infected with hepatitis C virus(HCV). Methods The presences of CD27 and CD28 on the surface of CD8⁺ T-cell were monitored using flow cytometry in 40 patients chronically infected with HCV before treatment with pegylated alpha interferon and ribavirin. The differentiations of CD8⁺T cell were assessed at early stage(CD28⁺/CD27⁺), intermediate stage(CD28^-/CD27⁺) and late stage(CD28^-/CD27^-). Then, a comparison on differentiations of CD8⁺T cells between patients who presented a rapid virological response(RVR) to therapy and those who did not show any RVR(no RVR) was performed. Results A clear difference in the presences of CD27 and CD28 on the surface of CD8⁺ T-cell was found: in patients with RVR, the percentages of CD27 and CD28 were much higher than those in patients without RVR, the difference was significant(P=0.004 and P=0.01, respectively). Moreover, the differentiations of CD8⁺T cells were compared between patients with RVR and without RVR: in patients with RVR, the dominant cells were the ones in early/intermediate stage, while, a late differentiation process of CD8 T cells might be associated with lack of rapid response to treatment. Conclusion The differentiations of CD8⁺ T cell before treatment are related to the rapid virological response to antiviral therapy in patients infected with HCV, this phenomenon indicates that cytotoxic T cell may be involved in the clearance of HCV during the treatment with interferon.

Key words: chronic hepatitis C, rapid virological response, cell differentiation