CYP1B1 and rheumatoid arthritis: We also found negative correlation in macrophage expression of miR-223 and CYP1A1 (p = 0.05; r = 0.60; Supplementary Fig S7a) and CYP1B1 (p = 0.03, r = 0.64; Fig. 5d), which suggests that miR-223 upregulation in RA CD14+ cells impairs AHR/ARNT-mediated transcription.