This may mimic events in vivo in which an inflammatory hepatic cytokine microenvironment, found in hepatitis or cancer, dominated by IL‐1, IL‐2, IL‐6, IL‐12, IL‐15, IL‐18, IFNα, IFNγ, and TNFα/β 38, 39, may lead to the expansion of CD49a+ NK cells. This evidence concerns the gene IL15 and hepatitis A virus infection.