Dynamics of CD81 expression on lymphocyte subsets during interferon-alpha-based antiviral treatment of patients with chronic hepatitis C.

CD81 is a hepatitis C virus (HCV) coreceptor with important functions in lymphocytes. During treatment, CD81 expression may be changed directly by the antiviral therapy or indirectly by reduction of the HCV serum level. The regulation of CD81 on lymphocyte subtypes has not been investigated so far and may be relevant for the control of viral infection and treatment response. CD81 was analyzed by flow cytometry in CD8(+), CD4(+), CD19(+), and CD56(+) lymphocyte subtypes from 20 patients with chronic hepatitis C before, during, and after antiviral treatment with pegylated interferon-alpha (IFN-alpha) and ribavirin. A sustained virologic response (SVR) was achieved in 11 patients. Dynamics of CD81 were investigated in correlation with HCV-RNA dynamics and the outcome of therapy. During treatment, the following typical patterns of CD81 regulation were observed: down-regulation on CD8(+) T cells (P = 0.022) and most significantly, on CD56(+) natural killer cells (P < 0.001), transient up-regulation on CD19(+) B cells (P = 0.006), and weak and late down-regulation on CD4(+) T cells (P = 0.028). During treatment, CD81 expression was not associated with the HCV-RNA serum level on all lymphocyte subtypes. After end of treatment, CD81 increased again in CD8(+) and CD56(+) cells (P = 0.001, P = 0.002). On CD8(+) T cells post-treatment, CD81 remained lower in patients who achieved a SVR compared with patients who failed to eliminate HCV after treatment (P = 0.033). Lymphocyte subsets show different patterns of CD81 response before and during antiviral treatment, which are associated with administration of IFN-alpha and antiviral response.