[Review] Blood and CSF biomarkers for multiple sclerosis: emerging clinical applications

Neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), chitinase-3-like protein 1 (CHI3L1), and other protein assays are being developed as diagnostic or prognostic biomarkers in multiple sclerosis. An increase in NfL concentrations reflects axonal damage resulting from the acute new inflammatory disease activity that occurs during a relapse. NfL concentrations can also reflect the occurrence of new MRI lesions. GFAP concentrations are increased in people with progressive forms of multiple sclerosis, and GFAP is an emerging biomarker of progression independent of relapses.