Impact of comorbid Sjögren syndrome in anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune neurological diseases of the central nervous system, which are characterized by the presence of serum anti-aquaporin-4 autoantibodies (AQP4-IgG). An association between Sjogren syndrome (SjS) and AQP4-IgG-positive NMOSD has been proposed, but the rate of coexistence has not been determined. In this study, 4,447 patients suspected of having NMOSD with acute neurological episodes were evaluated for the positivity of serum AQP4-IgG, serum SS-A/Ro antibody, and the presence of SjS-related symptoms (dry eye, dry mouth). Of the 4,447 patients, 1,651 were positive for serum AQP4-IgG, and the remaining 2,796 were negative. A significantly higher proportion of AQP4-IgG-positive patients were positive for serum anti-SSA/Ro antibody (26.3 vs. 4.5%; p