This cross-sectional study examined Helicobacter pylori seropositivity in Japanese MS patients versus healthy controls, finding H. pylori antibody prevalence was significantly lower in conventional MS patients (22.6%) compared to healthy controls (42.4%) and opticospinal MS patients (51.9%). In conventional MS patients, H. pylori seropositivity showed protective associations with disability severity and MRI disease dissemination, supporting a protective role against MS development. This finding provides epidemiological evidence for the hygiene hypothesis: chronic bacterial infection with H. pylori provides immune stimulation that protects against autoimmune disease.
H. pylori's protective mechanism likely involves chronic antigenic stimulation promoting immune tolerance and shifting immune responses away from self-reactivity. This finding parallels the malaria observations, suggesting multiple chronic infections provide immunological training that prevents MS. The protective effect appears specific to conventional MS rather than opticospinal variants, suggesting pathogenic differences between MS types. For understanding MS prevention, the research indicates that early-life infections (even with pathogens like H. pylori) may provide protective immune training, supporting selective rather than aggressive antimicrobial approaches during childhood development.
