Throat microbiota alterations in patients with hereditary angioedema

BACKGROUND: Hereditary angioedema (HAE) is a rare disease characterized by recurrent episodes of cutaneous and submucosal edema. The clinical course of HAE is heterogeneous and unpredictable. There are no reliable indicators associated with angioedema attacks and severity. Throat microbiota plays vital roles in the maintenance of human health, while its association with HAE is barely understood. Therefore, this study aimed to investigate the alteration of throat microbiota and its correlation with attacks severity in HAE patients. METHODS: Throat swab samples were collected from HAE patients and their healthy family members, and then subjected to 16S rRNA sequencing. Alpha and beta diversity were used to examine the diversity and structure of bacterial communities. The relative abundance of individual bacteria was compared between study groups to determine the discriminant taxa. Spearman's correlation and linear regression were applied to analyze the correlation between throat bacteria and attacks severity. RESULTS: Irrespective of the study groups, the throat microbiome was predominantly occupied by Firmicutes, Bacteroidetes, Proteobacteria, and Fusobacteria. The recent onset of laryngeal edema is associated with the altered composition of microbiome community in HAE patients. The relative abundance of Bacteroidetes and Prevotellaceae was significantly increased in patients with recent episodes of laryngeal edema, compared to patients without recent episodes of laryngeal edema. Additionally, HAE attack severity scores positively correlated with the relative abundance of Bacteroidetes. CONCLUSION: We reported alterations of the throat microbial communities in HAE patients and explored the correlation between bacteria and edema severity, which may shed light on understanding the disease course and developing new therapeutic strategies for HAE.