AHR and rheumatoid arthritis: Unlike the abnormally elevated expression of AHR found in synovial tissues from patients with rheumatoid arthritis, overactivation of the AHR pathway regulates cytokine expression, including growth factors, which may promote inflammation and bone destruction mediated by activated macrophages, osteoclasts, dendritic cells, and suppressed osteoblasts.36, 37, 38 These findings suggest a shift in cell expression profiles across tissues and disease states and involve the interaction between innate and adaptive immunity.