IFNG and rheumatoid arthritis: CD4+ T cells producing T-helper type (Th)-1 (interferon gamma (IFNγ)) and Th17 cytokines (interleukin (IL)-17) [2-5], as well as B cells of the adaptive immune system and macrophages and dendritic cells (DCs) of the innate immune system all contribute to joint inflammation and immunopathology of RA.