CSF2 and rheumatoid arthritis: Baricitinib is an oral, selective JAK1/JAK2 inhibitor with lower potency for JAK3, modulating pro-inflammatory cytokines (IL-6, TNF-α, IL-8, IFN-α/γ, GM-CSF) and indirectly regulating T-cell activation and cytokine-mediated inflammation in RA [106].