567 Gut dysbiosis is associated with the development of alopecia areata

Alopecia areata (AA) is a highly prevalent autoimmune disease (AD) leading to hair loss in affected individuals, which both genetic and environmental factors likely play role. Associations between changes the microbiome composition many ADs have been reported, however, characterization of role gut microbiota development AA has not undertaken. To investigate functional relevance vivo, we depleted C3H/HeJ mouse model with broad-spectrum antibiotics. We found that antibiotic-treated mice were protected from induction. Additionally, using 16S rRNA gene sequencing (16SrRNA Seq) AA-affected show an overrepresentation single species Ligilactobacillus, Ligilactobacillus murinus (L. murinus), preceded first clinical signs AA. Further, L. specific primers, showed co-housed reduced levels comparison AA, suggesting associated Examining effects on T cell composition, microbiota-depleted had decreased percentage effector CD8+ cells skin draining lymph nodes, previously be required drive pathogenesis establish these observations human performed 16SrRNA Seq metagenomics compared stool samples patients healthy controls (HCs). discovered striking dysbiosis HCs identified Lachnospiraceae Bacteroidaceae overrepresented Taken together, findings suggest contributes offer new avenues treatment for this disease.