[Multiple sclerosis: disease entity, subtypes and variants, and diagnostic criteria]

Area of Science:

• Neuroimmunology
• Neurology
• Pathology

Background:

• Multiple sclerosis (MS) is a central nervous system (CNS) inflammatory demyelinating disorder.
• Classical MS (Charcot variant) affects all CNS parts, often progressing from relapsing-remitting to chronic progressive forms, though chronic forms are less common in Japanese populations.
• MS lesions exhibit perivenular demyelination, inflammation, gliosis, and axonal damage, with heterogeneity in lesion characteristics.

Purpose of the Study:

• To review current understanding of multiple sclerosis (MS) pathogenesis, lesion characteristics, and diagnostic criteria.
• To discuss the role of T-cell and B-cell mediated mechanisms in autoimmune damage to myelin and oligodendroglia.
• To highlight advancements in MS diagnosis, including new criteria incorporating MRI for morphological and temporal assessment.

Main Methods:

• Review of existing literature on MS pathology, immunology, and diagnostic advancements.
• Analysis of lesion morphology, including demyelination, inflammation, gliosis, and axonal damage.
• Examination of proposed and established diagnostic criteria for MS, including the McDonald criteria (2001).

Main Results:

• MS lesions are heterogeneous, involving autoimmune attacks on myelin/oligodendroglia via T-cell and B-cell mechanisms.
• Axonal damage can be extensive early in the disease course.
• Candidate antigens include myelin proteins and potentially viral/microbial proteins sharing epitopes.

Conclusions:

• Updated diagnostic criteria, such as the McDonald criteria, incorporate MRI for improved MS diagnosis.
• Research is ongoing to refine diagnostic criteria, particularly for Japanese MS patients.
• Understanding MS pathogenesis and lesion heterogeneity is crucial for developing effective treatments.