Intestinal microbiota changes in Graves' disease: a prospective clinical study.

Graves' disease (GD) occurs due to an autoimmune dysfunction of thyroid gland cells, leading to manifestations consistent with hyperthyroidism. Various studies have confirmed the link between autoimmune conditions and changes in the composition of intestinal microbial organisms. However, few studies have assessed the relationship between the GD and the changes in intestinal microbiota. Therefore, the present study aimed to investigate changes in intestinal flora that may occur in the setting of GD. Thirty-nine patients with GD and 17 healthy controls were enrolled for fecal sample collection. 16S rRNA sequencing was used to analyze the diversity and composition of the intestinal microbiota. High-throughput sequencing of 16S rRNA genes of intestinal flora was performed on Illumina Hiseq2500 platform. Comparing to healthy individuals, the number of Bacilli, Lactobacillales, Prevotella, Megamonas and Veillonella strains were increased, whereas the number of Ruminococcus, Rikenellaceae and Alistipes strains were decreased among patients with GD. Furthermore, patients with GD showed a decrease in intestinal microbial diversity. Therefore, it indicates that the diversity of microbial strains is significantly reduced in GD patients, and patients with GD will undergo significant changes in intestinal microbiota, by comparing the intestinal flora of GD and healthy controls. These conclusions are expected to provide a preliminary reference for further researches on the interaction mechanism between intestinal flora and GD.