CHI3L1 forms a multimeric complex with IL-13Rα2 and IL-13 to activate the MAPK/Erk, Akt, and Wnt/β-catenin cell signaling pathways to regulate apoptosis, oxidant injury-induced cell death, Streptococcus pneumonia-induced macrophage pyroptosis and inflammasome activation, antibacterial response, and melanoma metastasis.18 A recent study reveals that N-glycosylation is a critical determinant of CHI3L1 and IL-13 binding to IL-13Rα2.94 CHI3L1 and IL-13 do not compete for IL-13Rα2 binding and signaling, and they do not bind to identical locations on IL-13Rα2. This evidence concerns the gene IL13 and streptococcal pneumonia.