A1.3Increased CD5highFasLhigh B regulatory cells in patients with active HCV infection: association with disease severity and autoimmunity

B regulatory cells are a well-established subtype of B cells appreciated as a front player in maintaining self-tolerance and preventing inflammation and autoimmunity. On the other hand, enhanced function of B regulatory cells (in similarity with that of T regulatory cells) is responsible (at least in part) for the failure of cytotoxic T lymphocytes in preventing malignancy spread and eliminating infections, mainly intracellular. CD5high B cells were reported to be IL-10 producers and also highly expressing Fas lignad (FasL), thus considered to be regulatory cells. In this study we aim to analyse the status of these cells, in patients suffering from active chronic hepatitis C virus (HCV). We first assessed the status of CD5high B cells in HCV infected patients (n = 15) and compared this to healthy individuals (n = 15). Here we found that CD5high B cells are significantly increased in HCV patients when compared to healthy individuals (37.0 plus or minus 5.2 vs. 21.3 plus or minus 7.1, respectively; p < 0.01). In addition, CD5high B cells were shown to highly express FasL in patients when compared to healthy controls (40.0 plus or minus 8.2 vs. 23.6 plus or minus 6.4, respectively; p < 0.001). Increased FasL expression was noticed to be in association with increased viral load, disease severity and autoimmunity. This is the first report on CD5high/FasLhigh B regulatory cells to be increased in chronic HCV patients. CD5highFasLhigh B cells may enhance the process of cytotoxic T cell apoptosis, suggesting this to be one of the mechanisms by which HCV escapes T cell cytotoxic response.