Neutrophil-to-Lymphocyte Ratio: a Marker of Neuro-inflammation in Multiple Sclerosis Patients: a Meta-analysis and Systematic Review

Multiple sclerosis (MS) is a prevalent chronic inflammatory disease of the CNS. There is a growing need for a reliable marker for MS diagnosis and disease monitoring. We aimed to assess the potential of the neutrophil-to-lymphocyte ratio (NLR) as a biomarker for MS diagnosis as well as the prediction of relapses and disability. We searched MEDLINE, Scopus, Web of Science, and Embase for relevant studies. The main outcome was the mean difference in NLR between MS patients and healthy controls and different subtypes of MS. We also calculated the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for NLR for diagnosis of MS and MS activity and disability. NLR was significantly higher in MS patients than in healthy controls (MD = 0.69; 95% CI, 0.48–0.9). Also, NLR was significantly higher during relapse than remission (MD = 1.26; 95% CI, 0.37–2.16). Regarding the performance of NLR as a marker for MS activity, its pooled sensitivity and specificity were 0.56 (95% CI 0.52–0.76) and 0.92 (95% CI 0.86–0.95), respectively; also, positive likelihood ration and negative likelihood ratio were 9.85 (95% CI 1.87–51.94) and 0.39 (95% CI 0.28–0.54) respectively. NLR can serve as an adjunctive biomarker for diagnosing MS and identifying relapse periods. However, the clinical utility of NLR in MS is yet to be confirmed by future large, prospective studies with longer follow-ups.