2023 年 40 巻 4 号 p. 598-605
Myelin oligodendrocyte glycoprotein (MOG) is one of the myelin sheath component which exclusively expressed in the central nervous system. Recently, cell–based assays have provided the identification of conformation–sensitive MOG antibodies, establishing the disease concept of MOG antibody–associated disease (MOGAD).
Based on previous case reports, demyelinating lesions in MOGAD have been considered to have MS Pattern II features. However, we and others recently conducted a detailed histopathological analysis of MOGAD and revealed that the lesions were characterized by ADEM–like perivenous demyelination and the fusion pattern localized in both the white and gray matters, but not by MS–like radially expanding confluent demyelination. We also found that one–third of the demyelinating plaques in MOGAD showed that decrease of MOG staining was greater than those of other myelin proteins, suggesting a MOG–targeted pathology in the disease. Unlike the AQP4 antibody–positive NMOSD, no destructive changes in astrocytes or AQP4–loss were observed. Perivascular cuffings were mainly consisted of macrophages and T cells with CD4–dominancy, which is also different from CD8+ T cell–dominant inflammation in MS. Meanwhile the pathogenetic contribution of complements in MOGAD is still under debate, as the reported results have been inconsistent.
MOGAD is considered an independent disease concept in inflammatory demyelinating diseases in terms of histopathological features. However, the clinical phenotype of MOGAD and its response to treatment is variable between cases. Further research is need to clarify the exact mechanism of demyelination and how the pathophysiology affects the clinical phenotype and disability in MOGAD.
