TNF and rheumatoid arthritis: By secreting a large number of cytokines such as TNF, IL-6, IL-1, and IL-12 and differentiation factors such as the macrophage colony-stimulating factor (M-CSF) and fibroblast growth factor (FGF), both cDCs and pDCs contribute to RA pathogenesis (Saferding and Blüml, 2020).