CHI3L1 and in situ carcinoma: In a multivariable Cox regression analysis including radiological abnormalities at baseline, presence of IgG oligoclonal bands, treatment, and age at CIS onset as covariates, patients with high CSF levels of CHI3L1 had a 4-fold increased risk for the development of neurological disability compared to CIS patients with low CSF CHI3L1 levels at the time of the first neurological event2.