Probiotics-regulated lithocholic acid suppressed B-cell differentiation in neuromyelitis optica spectrum disorder.

Intestinal microbes play a crucial role in gut health and the immune-mediated central nervous system through the "gut-brain" axis. However, probiotic safety and efficacy in Neuromyelitis optica spectrum disorder (NMOSD) are not well-explored. A pilot clinic trial for NMOSD with probiotic intervention revealed alterations in the microbiota (increased Anaerostipes, Bacteroides; decreased Granulicatella, Streptococcus, Rothia). Metabolite analysis showed elevated 2-methylbutyric and isobutyric acids, reduced lithocholic acid (LCA), and glycodeoxycholic acid (GDCA). Immune markers Interleukin (IL-7), vascular endothelial growth factor (VEGF-A), and B lymphocyte chemoattractant (BLC) decreased, while plasma cells and transitional B cells increased post-probiotics, suggesting potential immunomodulatory effects on NMOSD.