TNF and hepatitis A virus infection: In the Con A-induced hepatitis model, in addition to cytokine production (IFN-γ, IL-4, TNF-α), it has been also shown that activated iNKT cells also upregulate FAS-L on their surface and induce hepatocyte apoptosis through the FAS/FAS-L pathway which appears to be an important mechanism for liver damage, as iNKT cells from FAS-mutant gld/gld mice fail to induce hepatitis (2).