CHIA degrades chitin and chitotriose. May participate in the defense against nematodes and other pathogens. There are 3 named isoforms produced by alternative splicing. CHIA is induced via a T helper-2 (Th2)-specific, interleukin-13-mediated pathway in epithelial cells and macrophages. CHIA may be an important mediator of IL13-induced responses in Th2-dominated disorders such as asthma. CHIA hydrolysis N-acetyl-beta-D-glucosaminide 1,4-beta-linkages in chitin and chitodextrins.Synonyms: Acidic mammalian chitinase, CHIA, Lung-specific protein TSA1902, TSA1902