TNF and viral infectious disease: Group 1 innate lymphoid cells (ILC1s) produce the typical type 1 cytokines interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα) and therefore participate in a type 1 immune response aimed at the clearance of intracellular bacterial and viral infections via macrophage recruitment and antigen specific Th1-mediated cell clearance [2].