MOG-IgG Frequency in Multiple Sclerosis: Diagnostic Challenges With Low-Titer Results

Area of Science:

• Neuroimmunology
• Autoimmunity
• Neurological Disorders

Background:

• Myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) positivity presents diagnostic challenges in people with multiple sclerosis (pwMS).
• Previous studies on MOG-IgG prevalence in pwMS are primarily from Caucasian populations.
• Understanding MOG-IgG frequency in diverse ethnic groups, like Asian populations, is crucial for accurate diagnosis.

Purpose of the Study:

• To determine the prevalence of MOG-IgG in a large, predominantly Asian cohort of people with multiple sclerosis (pwMS).
• To assess the diagnostic utility of MOG-IgG testing in a non-Caucasian MS population.
• To investigate the frequency of low-titer MOG-IgG positivity and its implications for MS diagnosis.

Main Methods:

• Serum samples from 405 pwMS diagnosed by 2017 McDonald criteria were analyzed.
• An in-house live cell-based assay was used to detect MOG-IgG at 1:20 dilution.
• Positive or borderline samples underwent retesting at 1:100 dilution by blinded investigators.

Main Results:

• The study included 405 pwMS, with 98% being of Asian ethnicity.
• Overall MOG-IgG positive or borderline results were found in 1.5% of the cohort.
• Clear MOG-IgG positivity was rare (0.3%), with 1.2% showing low-titer positive or borderline results.

Conclusions:

• True MOG-IgG positivity is uncommon in people with multiple sclerosis across different populations.
• Low-titer MOG-IgG positive or borderline results can complicate the diagnosis of MS.
• Comprehensive clinical evaluation and repeat testing at higher dilutions are essential to avoid misdiagnosis.