JAK2 and rheumatoid arthritis: In RA-ILD cases with a usual interstitial pneumonia (UIP) pattern, the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway has been implicated in mediating transforming growth factor-beta (TGF-β)-driven myofibroblast activation, thus playing a central role in the fibrotic remodeling of the lung parenchyma [58].