Neutrophil-to-lymphocyte ratio: a marker of neuro-inflammation in multiple sclerosis?

Background: The significance of neutrophil-to-lymphocyte ratio (NLR) has been explored in different diseases. Few studies addressed its role in patients with multiple sclerosis (MS), with promising results regarding its association with disease activity or disability. Objectives: We aimed at confirming the role of NLR as a marker of neuro-inflammation in a cohort of newly diagnosed MS and clinically isolated syndrome (CIS) patients. Furthermore, we compared the validity of NLR with established markers of neuro-inflammation, such as serum neurofilament light chain (Nfl), CSF microvesicles (CSF-MVs) and CSF IgG indices. Methods: We retrospectively selected, from a prospectively collected cohort of newly diagnosed MS/CIS patients hospitalized for diagnostic work-up, 121 patients who underwent CSF examination, brain MRI and blood cell count within the time of hospitalization and did not receive steroid treatment before sample collection. Patients were grouped according to presence of gadolinium enhancement at brain MRI. Results: No association was found between NLR and disease activity, nor with other clinical measures. Nfl, CSF-MVs, Link and Tourtellotte indices were significantly higher in patients with brain MRI activity. Conclusions: Our negative results do not support the use of NLR as a marker of disease activity and disability in patients with MS.