IL4R and chronic obstructive pulmonary disease: Associations among PAR-2, interleukin-4 receptor (IL-4R), transforming growth factor (TGF)-β and thymic stromal lymphoprotein (TSLP) have already been investigated in bronchial asthma, chronic obstructive pulmonary disease (COPD) (10) and idiopathic lung fibrosis (11).