CSF2 and viral infectious disease: NK cells have key roles in the innate immune response by killing transformed cells, as consequence of viral infections or oncogenesis; NK cells are also major sources of pro-inflammatory cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon gamma (IFN-γ), which can restore or activate the antiviral property of the myeloid compartment; thus, any decrease in these cell populations may alter the ability to clear viruses (32).