Chitinase-3-Like Protein 1 (CHI3L1) belongs to the glycosyl hydrolase 18 family. CHI3L1 is expressed in activated macrophages, articular chondrocytes, synovial cells as well as in liver. It lacks chitinase activity and is secreted by activated macrophages, chondrocytes, neutrophils and synovial cells. CHI3L1 is thought to play a role in defense against pathogens, or in tissue remodeling, and in the capacity of cells to respond to and cope with changes in their environment. In addition, CHI3L1 is associated with susceptibility to asthma-related traits type 7 (ASRT7) which assessed by methacholine challenge test, serum IgE levels, atopy, and atopic dermatitis.