Gut Microbiota May Play a Significant Role in the Pathogenesis of Graves' Disease.

Gut microbiota are considered to be intrinsic regulators of thyroid autoimmunity. We designed a cross-sectional study to examine the makeup and metabolic function of microbiota in Graves' disease (GD) patients, with the ultimate aim of offering new perspectives on the diagnosis and treatment of GD. The 16S ribosomal RNA (rRNA) V3-V4 DNA regions of microbiota were obtained from fecal samples collected from 45 GD patients and 59 controls. Microbial differences between the two groups were subsequently analyzed based on high-throughput sequencing. Compared with controls, GD patients had reduced alpha diversity ( < 0.05). At the phylum level, GD patients had a significantly lower proportion of ( = 0.008) and a significantly higher proportion of ( = 0.002) compared with the controls. At the genus level, GD patients had greater numbers of and , although fewer , , , , , , and than controls (all  < 0.05). Subgroup analysis of GD patients revealed that may play a key role in the pathogenesis of autoimmune thyroid diseases. Nine distinct genera showed significant correlations with certain thyroid function tests. Functional prediction revealed that may be an important microbe in certain metabolic pathways that occur in the hyperthyroid state. In addition, linear discriminant analysis (LDA) and effect size (LEfSe) analysis showed that there were significant differences in the levels of 18 genera between GD patients and controls (LDA >3.0, all  < 0.05). A diagnostic model using the top nine genera had an area under the curve of 0.8109 [confidence interval: 0.7274-0.8945]. Intestinal microbiota are different in GD patients. The microbiota we identified offer an alternative noninvasive diagnostic methodology for GD. Microbiota may also play a role in thyroid autoimmunity, and future research is needed to further elucidate the role.