Neuromyelitis optica spectrum disorders: still evolving and broadening

Area of Science:

• Neuroimmunology
• Neurology
• Pathology

Background:

• Diagnostic criteria for Neuromyelitis Optica Spectrum Disorders (NMOSD) have undergone significant revisions over the past two decades.
• Accumulated pathological and therapeutic data have refined the understanding of NMOSD.
• This review details the evolution and expansion of the NMOSD concept.

Purpose of the Study:

• To provide an overview of the evolution and broadening of the concept of NMOSD.
• To discuss the classification of NMOSD into aquaporin-4 (AQP4)-antibody-seropositive and seronegative subtypes.
• To highlight the unique aspects of myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive NMOSD.

Main Methods:

• Review of diagnostic criteria revisions over the past 20 years.
• Analysis of accumulated pathological and therapeutic data.
• Classification of NMOSD based on antibody status (AQP4 and MOG).

Main Results:

• NMOSD is now classified into AQP4-antibody-seropositive and seronegative categories, enabling earlier detection.
• Seronegative NMOSD includes MOG-antibody-seropositive disease, presenting a distinct clinical spectrum.
• Pathologically, NMOSD involves autoimmune astrocytopathy (AQP4-antibody) and inflammatory demyelinating disease (MOG-antibody).
• Therapeutic options for NMOSD have advanced, including clinical trials of monoclonal antibodies.

Conclusions:

• Clinical, pathological, and therapeutic concepts of NMOSD have evolved significantly due to antibody discoveries.
• Double seronegative NMOSD remains a focus for research, prompting a re-evaluation of NMOSD definitions.
• Understanding the distinct pathological and clinical features of AQP4-antibody and MOG-antibody-seropositive NMOSD is crucial for patient management.