CD4 and chronic hepatitis C virus infection: In chronic hepatitis C, HCV typically escapes both innate and adaptive responses [57] thanks to the release of several factors promoting viral immune evasion and globally impairing viral clearance [72], a complex immune mechanism named “T cell exhaustion”, typically characterized by CD4+ T cell and CD8+ T cell dysfunction together with impaired cytokine production and lack of response to antigen stimulation [73,74].