The neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in patients with neuromyelitis optica spectrum disorders and multiple sclerosis.

Background: This study aimed to investigate the differences in neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) between patients with neuromyelitis optica spectrum disorders (NMOSDs) and multiple sclerosis (MS), as well as their potential associations with disease onset and progression. Methods: Clinical, laboratory, and imaging data of NMOSD and MS patients admitted to Peking University Third Hospital were retrospectively analyzed. Blood test results within 1 week of new clinical symptoms or imaging abnormalities were used to calculate NLR and PLR. These ratios were compared with those of 100 healthy controls. Results: A total of 79 NMOSD patients, 75 MS patients, and 100 healthy controls were included. The mean age of NMOSD patients was significantly higher than that of MS patients (p = 0.012). The Expanded Disability Status Scale (EDSS) scores at onset and after 1 year were significantly higher in NMOSD patients compared to MS patients (both p = 0.002). NLR was significantly elevated in NMOSD patients compared to both MS patients and healthy controls (p = 0.002 and p = 0.001, respectively), while no significant difference was observed between MS patients and healthy controls (p = 0.407). No significant differences in PLR were found among the three groups. After adjusting for age and gender, significant differences in NLR but not PLR remained between NMOSD and MS patients (p = 0.010 and p = 0.364). Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.717 for NLR (p = 0.001, 95% CI: 0.636-0.798) and 0.567 for PLR (p = 0.152, 95% CI: 0.476-0.658) in distinguishing NMOSD from MS. In NMOSD patients, baseline and 12-month EDSS scores were significantly lower in the low NLR group (NLR < 2.44) compared to the high NLR group (NLR ≥ 2.44; both p = 0.008). Similarly, in MS patients, baseline and 12-month EDSS scores were significantly lower in the low NLR group (NLR < 1.68) compared to the high NLR group (NLR ≥ 1.68; both p = 0.003). Conclusion: NLR may serve as a useful auxiliary tool for differentiating acute attacks or relapses of NMOSD from MS and is associated with prognosis in both NMOSD and MS patients.