CHI3L1 and Alzheimer disease: Colton et al. probed cortical tissue from patients with AD for markers of alternative activation and found increased Arginase-1 (Arg1), Cluster of Differentiation 206 (CD206), Chitinase-3-like protein 1 (Chi3 l1), Chitinase-3-like protein 2 (Chi3 l2), and TNF-α, with unchanged expression of inducible nitric oxide synthase (iNOS) and IL-1β [32].