2025 American Academy of Neurology Abstract Website

Objective:

This study aimed to investigate the impact of seasonality on myelin oligodendrocyte glycoprotein (MOG)-IgG positivity rates, disease onset, and attacks of MOG antibody-associated disease (MOGAD).

Background:

Studies on seasonal variation in MOG-IgG positivity, disease onset, and attacks of MOGAD are limited.

Design/Methods:

This retrospective study firstly utilized big data from the Mayo Clinic Neuroimmunology Laboratory, where MOG-IgG sera were tested using a live cell-based assay from July 2014 to April 2024. Secondly, we reviewed the medical records of MOGAD patients from Mayo Clinic and external collaborations. The month of testing in the laboratory cohort and the month of disease onset and attacks in the clinical cohort were recorded.

Results:

Among 90,094 patient sera tested for MOG-IgG, the highest proportion of MOG-IgG positivity was in winter (7.4%, 1,762/23,809), while the lowest was in summer (6.6%, 1,500/22,895;p=0.003). January had the highest rate (7.5%, 586/7,812), whereas July was the lowest (6.2%, 451/7,220;p=0.072). Similarly, the frequency of high-titer MOG-IgG (≥1:1,000) was highest in winter (2.3%, 547/23,809) and lowest in summer (1.7%, 390/22,895;p<0.001). December had the highest rate of high-titer cases (2.3%, 182/7,857), while July had the lowest (1.5%, 108/7,220;p=0.002).

Among 431 patients with available clinical data, disease onset was most frequent in winter (31.3%, 135/431) and least common in summer (20.6%, 89/431;p=0.003). January had the highest number of onset cases (14.8%, 64/431), while July had the fewest (6.7%, 29/431;p<0.001). Similarly, of the 994 recorded attacks, the highest frequency occurred in winter (30.5%, 303/994), with the lowest in summer (22.2%, 221/994;p<0.001). January had the most attacks (14%, 139/994), while July had the fewest (7.0%, 70/994;p<0.001).

Conclusions:

This study found increased MOG-IgG positivity, disease onset, and disease activity during winter, particularly in January. Further investigation is needed to understand the mechanisms behind this seasonal pattern and its implications for patient management.