Among these, chitotriosidase, acidic mammalian chitinase (true chitinases), and BRP-39/YKL-40 (CHI3L1; a chitinase-like protein or CLP) may have chitin-like targets and can modulate host immune responses during infections, allergy, tissue injury, inflammation, and tumor. The gene discussed is CHI3L1; the disease is allergic disease.