[Chitotriosidase of human macrophages and mammalian chitinases: biological functions and abnormalities in pathology].

Recently discovered human chitotriosidase is a member of chitinase family capable to hydrolyze chitin, a polymer of N-acetylglucosamine. Serum and plasma chitotriosidase activity is usually measured as the first step in diagnosis of Gaucher disease. Monitoring chitotriosidase activity is widely used during treatment of this pathology by enzyme replacement therapy. Its elevated plasma level reflects gradual intralysosomal accumulation in Gaucher cells (lipid-loaded macrophages). Macrophages overloaded by the enzyme accumulated in lysosomal material (lipids) were shown to secrete chitotriosidase; its increased expression was noted in several lysosomal storage diseases and atherosclerosis. We observed enhanced chitotriosidase activity in healthy young and elderly persons probably associated with the development of atherosclerosis and plaque formation. Chitotriosidase is believed to play a role in mechanisms of immunity and protection against chitin-containing pathogens.