CX3CR1 and viral infectious disease: We investigated the frequencies of virus-specific CX3CR1+CD8+ T cells in patients suffering from chronic viral infection, such as chronic Hepatitis B and chronic Hepatitis C. As expected, we could only rarely detect virus-specific CX3CR1+CD8+ T cells in the blood of these patients (Fig. 7a), in contrast to cytomegalovirus (CMV)-specific CD8+ T cells from the same donors (Fig. 7a).