NMO Vs. Multiple Sclerosis: Are the associated autoimmune diseases the same?"

Abstract

Introduction: Neuromyelitis Optica Spectrum Disorder (NMOSD) and Multiple Sclerosis (MS) are demyelinating diseases of the central nervous system (CNS). Autoimmunity in patients with demyelinating diseases has been broadly investigated. Many studies have suggested a higher prevalence of Autoimmune Disorders (AID) in these diseases. Objective: To study the characteristics of our patients with NMOSD alone versus NMOSD plus AID and to compare them between NMOSD and Multiple Sclerosis. Methods: From an existing database of NMOSD until November 2018, we identified patients with NMOSD from December 2018 to January 2020, 34 in total, and we searched in all these patients the presence AID (7 in total). Between these two groups, the clinical, laboratory and demographic features were compared. We also selected patients with Multiple Sclerosis plus AID (66 in total) and we compared the AID associated with each of the CNS demyelinating diseases. Results: The mean age of patients with NMOSD alone was 43,52 (± 20,33); 63% were woman. The prevalence of AID in our group of patients with NMOSD was 20,59% (7/34). Three types of AID were identified autoimmune thyroiditis, Systemic lupus erythematosus, and Behçet Disease. All the associated AID were diagnosed before NMOSD. The clinical and demographic characteristics between NMOSD with and without AID were not statistically significant. The frequency of positivity for AQP-4 antibodies in the NMOSD plus AID group was 85,7% (p=0,002). The prevalence of AID in patients with Multiple Sclerosis was 10,4%. Fifteen types of AID were identified. Forty-four percent of concomitant AID was diagnosed before and in 47% it was diagnosed after the diagnosis of MS. Autoimmune thyroiditis was the most frequent AID in both NMOSD and MS patients (p=0,188). Systemic lupus erythematosus was significantly more prevalent in patients with NMOSD than MS (p = 0,001). Conclusion: The clinical and demographic features between NMOSD with and without AID were similar. Patients with NMOSD plus AID have a significantly higher prevalence of AQP-4 antibodies than patients without autoimmune disease. Some AID are more frequently associated with NMOSD than MS (e.g. SLE).