LAUSR

BACKGROUND Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system (CNS), also described as CNS autoimmune astrocytopathy, due to the production of pathogenic antibodies against aquaporin-4 (AQP4) expressed on the foot of astrocytes. NMOSD coexists with autoimmune diseases and related autoantibodies [anti-Sjogren's syndrome A (anti-SSA)/Ro antibody, anti-Sjogren's syndrome B (anti-SSB)/La antibody, anti-nuclear (anti-ANA) antibodies, anti-double-stranded DNA (anti-dsDNA) antibody, anti-thyroglobulin antibody, and anti-thyroid peroxidase antibody]. OBJECTIVES No precise conclusion has been drawn on the role of the anti-SSA/Ro antibody in NMOSD. Therefore, the aim of this work was to evaluate whether the anti-SSA/Ro antibody has an impact on the clinical manifestation or prognosis of NMOSD. METHODS Data were retrospectively collected from 102 patients with NMOSD diagnosed by experienced neurologists. The study population was divided into two groups based on the serum anti-SSA/Ro antibody status: NMOSD with or without anti-SSA/Ro antibody. The clinical, neuroimaging and laboratory parameters were compared between the two groups, including the neurological symptoms, MRI results, frequency of systemic autoantibodies, Expanded Disability Status Scale (EDSS), and NMOSD relapse rate. The EDSS and relapse were applied as measures of the NMOSD patient prognostic value. Cox regression analysis was used to evaluate the prognostic impact of anti-SSA/Ro antibody on NMOSD. RESULTS Among the 102 NMOSD patients, striking differences were observed in the positive rate of AQP4-IgG (89.2% vs. 72.3%, p = 0.046) between those patients with and without the anti-SSA/Ro antibody. In addition, NMOSD patients with anti-SSA/Ro antibody showed the presence of more frequent anti-ANA antibodies (p = 0.002), anti-SSB/La antibody (p < 0.001), anti-dsDNA antibody (p < 0.002), Sjogren's syndrome (SS, p < 0.001) and systemic lupus erythematosus (SLE, p = 0.045). Univariate and multivariate Cox regression analysis were performed to confirm that the anti-SSA/Ro antibody affected the EDSS score and the relapse of NMOSD patients. The analysis of the survival curve revealed that the EDSS score in the NMOSD patients positive for the anti-SSA/Ro antibody reached 4.0 (p = 0.035) and relapsed (p = 0.039) earlier than in the negative group. CONCLUSION The anti-SSA/Ro antibody could be associated with disease activity and severe disability in NMOSD.