Similarly, CHI3L1 levels are higher in the CSF, serum and plasma of people with MS and are associated with Expanded Disability Status Scale (EDSS), relapse rate, MRI lesion load and prognosis.8 13 These biomarkers reflect neurodegenerative or inflammatory processes and are not specific to MS or demyelinating diseases. The gene discussed is CHI3L1; the disease is myeloid sarcoma.