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.

中文翻译：

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几丁质、几丁质酶和几丁质酶样蛋白在儿科肺部疾病中的作用

几丁质仅次于纤维素，是地球上第二丰富的生物聚合物，是昆虫、真菌和屋尘螨的关键成分。低等生命形式被赋予几丁质酶，以抵御携带几丁质的病原体。出乎意料的是，还发现人类表达几丁质酶以及调节免疫反应的几丁质酶样蛋白。特别是，几丁质酶样蛋白 YKL-40 的水平升高与严重的哮喘、囊性纤维化和其他炎症性疾病有关。在这里，我们总结并讨论了几丁质、几丁质酶和几丁质酶样蛋白在儿科肺部疾病中的潜在作用。