CHIT1 has been implicated in both granulomatous and non-granulomatous inflammatory conditions, including multiple sclerosis, sarcoidosis, inflammatory bowel disease, and a few fibrotic interstitial lung diseases (tuberculosis, idiopathic pulmonary fibrosis, scleroderma-associated interstitial lung diseases, and chronic obstructive pulmonary diseases) [35,36,37,38,39]. This evidence concerns the gene CHIT1 and chronic obstructive pulmonary disease.