IL17RA and rheumatoid arthritis: Considering the lung involvement in RA, interesting data have emerged from studies on mice models deficient in the IL-17 receptor A (IL-17Ra−/−), showing that in two different mice models of pulmonary fibrosis employing COPD stimuli (cigarette smoking and viral mimetic polyinosinic-polycytidylic acid), animals were protected from both airway inflammation and fibrosis (76).