SPP1 and amyotrophic lateral sclerosis: Similar to the LC-MS/MS data, CHI3L2 levels showed approximately 2-fold increase (**p < 0.01 v/s N-CSF; no. of samples: N-CSF =13, ALS-CSF = 16) while osteopontin levels showed 1.9-fold increase in ALS-CSF compared to the control CSF (*p < 0.05 v/s N-CSF; no. of samples: N-CSF =13, ALS-CSF = 16) (Figure 2B & C).