These results, together with the above data, leading us to postulate that besides the well-known immunomodulatory action of Leflunomide via A77 1726, Leflunomide itself could activate AHR genomic signaling to inhibit CRP production and then attenuate bone erosion in CRPL RA, whereas the Leflunomide-AHR-CRP signaling was dysfunctional in CRPH RA (Fig. 3g). Here, AHR is linked to rheumatoid arthritis.