Lymphocyte subsets in renal allograft recipients with chronic hepatitis C virus infection

Background. The pathogenetic mechanisms of chronic hepatitis C virus (HCV) infection in renal allograft recipients are not well established. This study aimed to examine the relationship between altered immune status and HCV-related liver disease, by determining the changes in peripheral blood lymphocyte and natural killer (NK) cell subsets in these subjects. Methods. Peripheral blood lymphocyte, NK cell and activation markers were detected by flow cytometry in renal allograft recipients with (TpC+) or without (TpC-) HCV infection, and compared with age- and sex-matched patients with post-transfusional chronic HCV infection (TfC +) and healthy controls. Results. CD19+ cells were reduced in renal allograft recipients compared with controls. TpC + subjects had increased CD3+CD8+cells compared with controls, and increased CD3+DR+cells but reduced CD4+ CD38+ and CD3-CD16/56+ cells compared with controls as well as TfC + patients. TfC + patients and controls had similar numbers and proportions for the lymphocyte subsets and NK cells. Chronic liver disease in HCV-infected renal allograft recipients was associated with increased CD3 + CD16/56 + cells but reduced CD4+CD38+ cells. Reduction of CD3-CD16/56+ cells was noted in TpC+ subjects without liver disease. Yet among post-transfusional (TfC+) subjects this was associated with chronic hepatitis. Conclusions. Peripheral blood suppressor/cytotoxic T lymphocytes are increased, whereas activated helper/inducer T lymphocytes and NK cells are reduced, in renal allograft recipients with HCV infection. Increased non-MHC-restricted cytotoxic T cells and reduced NK cells are associated with the presence or absence of liver disease respectively. These data suggest that immune mechanisms are important in the pathogenesis of chronic hepatitis C after renal transplantation.