A recent study in the Chinese population revealed that patients with multiple sclerosis (MS) have higher immunoglobulin G (IgG) antibody levels against mycobacterium avium subspecies paratuberculosis (MAP) than healthy controls.
The higher IgG levels were found to be associated with higher Expanded Disability Status Scale (EDSS) scores, according to the Journal of Neuroimmunology.
“The positive association between MAP antibody titers and EDSS scores in MS patients without but not with the HLA-DRB104:05 allele indicates a possibility that MAP may be involved in the worsening disability of HLA-DRB104:05-negative MS patients,” Hayashi et al explained. None of the other clinical parameters assessed were associated with IgG levels.
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MAP is one of the bacteria that causes Johne’s disease in ruminants. Its infection in humans may result from the intake of dairy products. However this study did not find an association between dairy product consumption and MAP2694-IgG levels.
Previous studies in other populations suggest different susceptibilities to MAP infection. For instance, Japanese MS patients showed reactivity against the MAP2694259–303 peptide. In contrast, Italian MS patients showed higher antibody levels against several MAP peptides in addition to MAP2694259–303.
According to the study authors, MAP2694259–303 has high homology with T-cell receptor gamma-chain, phospholipase C, seizure protein 6, and transducin-like enhancer protein. Therefore, additional studies on the immunoreactivity to these homologous peptides might provide a better understanding of the increased reactivity to MAP2694259–303 observed in Japanese MS patients.
The prevalence of MAP in ruminants is also estimated to be far higher in the United States (70%), as well as in Australia and Europe (10%-60%), than in Japan (0.2%).
Altogether, the current knowledge indicates that MAP infection is rare among Japanese MS population.
Hayashi F, Isobe N, Cossu D, et al. Elevated mycobacterium avium subsp. paratuberculosis (MAP) antibody titer in Japanese multiple sclerosis. J Neuroimmunol. 2021;360:577701. doi:10.1016/j.jneuroim.2021.577701