CHIT1 and chronic obstructive pulmonary disease: CHIT1 has been implicated in the pathogenesis of multiple fibrotic lung diseases including idiopathic pulmonary fibrosis (IPF), sarcoidosis, chronic obstructive pulmonary disease (COPD), and asthma, as well as in other diseases with inflammatory or fibrotic phenotypes such as NASH, diabetic nephropathy, and ALS [5,6,8,9].