Clinical Characteristics of Anti-Myelin Oligodendrocyte Glycoprotein Antibody among Aquaporin -4 Negative Neuromyelitis Optica Spectrum Disorders in Egyptian Patients

Abstract

Neuromyelitis optica spectrum disorder is a severe inflammatory disease of the central nervous system characterized by a special predilection for the optic nerve and spinal cord (Jasiak-Zatonska et al., 2016). Its main pathogenic characteristic is the presence of anti-AQP4-Ab in the sera of patients with typical NMOSD phenotype. Some patients show negative sera for anti-AQP4-Ab and a proportion of them instead, express Abs to MOG (Unguraenu et al., 2018). Aquaporin-4 is expressed in the membrane of astrocytic end feet at the interfaces between blood and cerebrospinal fluid and brain parenchyma (Yick et al., 2018), while MOG is a molecule expressed on the outer lamella of the myelin sheath and may serve as an important surface marker of oligodendrocytes maturation, as well as it may have a role in myelin integrity, adhesion and cell surface interactions (Ramanthan et al., 2015). In the current study, we aimed to investigate whether anti-MOG-Abs could be used as a biomarker for NMOSD and whether its positivity is related to the clinical characteristics or it doesn’t have a relation with the disease course. Our study was performed on 40 -anti-AQP4-Ab negative NMOSD patients (6 children and 34 adults). Anti-MOG-Abs was tested in all included patients with an indirect immunofluorescence technique by CBA. Three (7.5%) of them were positive for anti-MOG-Abs. The clinical characteristic of anti-MOG-Abs was assessed in regard to the severity of the disease, and correlation with age and gender differences. The study showed that the presence of the anti-MOG-Abs in the serum of NMOSD patients is correlated with the disease course and induced disability as NMOSD patient with anti-MOG-Abs’ reactivity had significantly higher EDSS scores. On the other hand, anti-MOG-Abs positivity in NMOSD patients wasn’t significantly correlated with age, gender, positive family history nor smoking. In conclusion, anti-MOG-Abs can be associated with NMOSD patients and assess the disease-induced disability, subsequently, need different follow up and treatment plans.