CHI3L1 and amyotrophic lateral sclerosis: Recently, potential biomarkers have been suggested to diagnose ALS; the presence of these biomarkers in the blood (e.g.: percentage of monocytes, immunoglobulin M [IgM], and CD3 lymphocyte counts) or CSF (e.g.: Chitinase-3-like protein 1, Chitinase-3-like protein 2, Alpha-1-antichymotrypsin) raises the index of suspicion in favor of ALS, and may discriminate ALS from other MNDs (116, 117).