Cerebrospinal fluid immunological biomarkers associated with axonal damage in multiple sclerosis

Background and purpose Cerebrospinal fluid (CSF) neurofilament light protein (NFL) is a promising biomarker of axonal injury and neurodegeneration. Here CSF lymphocyte subpopulations and antibodies, potential players of neurodegeneration, are examined in relation to CSF NFL shedding in MS. Methods Cerebrospinal fluid NFL from 127 consecutive untreated MS patients was analysed. Samples from 37 age‐matched patients with other central nervous system non‐inflammatory neurological diseases (NIND) were also assessed. CD4+, CD8+, CD56+ and CD19+ cell subsets were studied by flow cytometry. Oligoclonal IgG and IgM bands (OCMB) against lipids were studied by isoelectric focusing and immunoblotting. These data were analysed in relation to clinical and magnetic resonance imaging features. Results A CSF NFL cut‐off value of 900 ng/l (mean + 3 SD of NIND values) was calculated. MS patients with increased NFL values showed significantly higher Multiple Sclerosis Severity Score and magnetic resonance imaging lesion number. The presence of OCMB (P