BAG3 and idiopathic interstitial pneumonia: Primary interstitial fibroblasts or precision cut lung slices (PCLS) of IPF lungs were treated with (1) the antifibrotic drug pirfenidone (Pirf), (2) the demethylating agent 5‐azacytidine (Aza), (3) the BAG3 modulator cantharidin (Ctd).