Double-Negative Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVES: Neuromyelitis optica spectrum disorder (NMOSD) is a severe condition usually associated with aquaporin-4 (AQP4) antibodies. A clinical presentation suggestive of NMOSD can also be associated with myelin oligodendrocyte glycoprotein (MOG) antibodies (MOGAD). NMOSD can be diagnosed in the absence of autoantibodies (double-negative NMOSD [DN-NMOSD]), but this subgroup has been poorly investigated. We conducted a systematic review and meta-analysis to define the clinical spectrum, prognosis, and treatment response in DN-NMOSD vs AQP4-NMOSD/MOGAD. METHODS: We searched on PubMed, Scopus, Embase, Google Scholar, Cochrane Library, and ClinicalTrials.gov databases of studies on patients fulfilling inclusion criteria. Patient characteristics, outcome measures, and treatment regimens were extracted. RESULTS: = 0.16). DISCUSSION: DN-NMOSD is a heterogenous, severe and highly relapsing disease, where attacks lead to irreversible dysfunction. The administration of maintenance immunotherapy reduces the relapse risk and should be considered early to prevent further disability.