JAK1 and rheumatoid arthritis: The values of OD/area of JAK-3 and STAT-1 were significantly increased in RA synovial tissues, when compared to HCs (JAK-3, p = 0.003; STAT-1, p = 0.007), as observed in Fig. 1E and F. Furthermore, the results showed that in RA, the intensity of fluorescence of JAK-1 and STAT-3 was significantly increased when compared to HCs (JAK-1, p < 0.0001; STAT-3, p = 0.0002).