A novel index, neutrophil-to-nonneutrophil ratio (NNR) as the predictive markers of disease activity in myelin oligodendrocyte glycoprotein antibody-associated disease: comparable with neutrophil-to-lymphocyte ratio (NLR)

초록

Introductions: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a CNS autoimmune disease affecting the brain, spinal cord, and optic nerve. The neutrophil-to-lymphocyte ratio (NLR) is related to autoimmune disease activity. Still, the clinical implication of NLR is unclear in patients with MOGAD. Objectives: We aimed to investigate the relationship between NRL and disease activity and discover the most useful index correlated with an attack in MOGAD. Methods: Using a prospective cohort of CNS demyelinating disease, we reviewed adult 42 patients with MOGAD (age 35.54±13.72 years; F: M=23:19), who had 427 blood samples for the analysis of cell count. We calculated NLR as [relative neutrophil count (%)/relative lymphocyte count (%)] and explored other indices to analyze their correlation of them with disease activity (attack vs remission). Results: NLR during the attack was higher than in remission in MOGAD (p<0.001). In addition, eosinophil-to-lymphocyte-ratio (ELR) and platelet-to-lymphocyte-ratio (PLR) were lower during attack than in remission (p<0.001 and p=0.006). Moreover, we discovered the novel index; neutrophil-to-nonneutrophil ratio (NNR) [relative neutrophil count (%)/ (100-relative neutrophil count (%))], which was also higher during attack than in remission (p <0.001). Using the receiver-operating characteristic (ROC) curve analysis, the optimal threshold of 3.65 for both NLR and N-ratio (neutrophil > 78.5%) was used to differentiate between acute attack and remission in MOGAD: sensitivity of 48.15% and specificity of 87.67%. Discussion: Our study suggests that NLR, ELR, PLR, and NNR could be used as supportive biomarkers for the attack, given that the clinical differentiation between relapses and pseudo-relapses can be challenging. Moreover, the novel index, NNR calculated by the neutrophil count only, may be the simplest and the most useful index to predict an attack in MOGAD.