Chitin, after cellulose, the second most abundant biopolymer on earth, is a key component of insects, fungi, and house-dust mites. Lower life forms are endowed with chitinases to defend themselves against chitin-bearing pathogens. Unexpectedly, humans were also found to express chitinases as well as chitinase-like proteins that modulate immune responses. Particularly, increased levels of the chitinase-like protein YKL-40 have been associated with severe asthma, cystic fibrosis, and other inflammatory disease conditions. Here, we summarize and discuss the potential role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases.
Keywords: AMCase; Asthma; BRP-39; CHIT1; Chitin; Chitinase-like proteins; Chitinases; Chitotriosidase; Cystic fibrosis; Fungi; Inflammation; Lung diseases; M2 macrophages; YKL-40.