Gut microbiome alterations in IgG4-related ophthalmic disease.

BACKGROUND: This study aims to investigate the gut microbiome alterations in IgG4-related ophthalmic disease (IgG4-ROD) and explore the potential roles of serum IgE and IgG4 in this disease. METHODS: In this prospective study, we recruited a total of 34 participants, including 17 IgG4-ROD patients and 17 healthy controls (HC) from Beijing Tongren Hospital. Fecal and blood samples were collected and analyzed, including 16 S rRNA gene sequencing of fecal samples. We assessed alpha and beta diversity to identify microbial variations among IgG4-ROD and HC, IgG4+ and IgG4-, IgE + and IgE-, and hormone-treated and untreated groups. Correlation analyses between cytokines and microbial profiles were conducted to uncover novel insights into the pathogenesis of IgG4-ROD. RESULTS: Significant differences in microbial composition were observed among subgroups. Patients with IgG4-ROD showed increases in Proteobacteria, Parvimonas, Novosphingobium, Shigella, and Allobaculum, along with decreased levels of Faecalibacterium, Barnesiella, and Weissella. The IgE + group exhibited an elevated abundance of Enterobacteriaceae, with several microbial changes overlapping between IgG4-ROD and IgE + individuals. Sphingomonas and Peptostreptococcaceae were more prevalent in the IgG4 + group, while Adlercreutzia and Acidimicrobiales were abundant in the IgG4- group. Furthermore, Ruminococcaceae were enriched in the HC and IgG4- groups. Pelomonas and Escherichia were increased in IgG4-ROD patients treated with glucocorticosteroids. Additionally, significant correlations were identified between several microbial taxa and serum cytokines such as IL-1β, IL-2, IFN-α, C3, and IgG4. CONCLUSION: The findings indicate gut dysbiosis in IgG4-ROD and suggest influential roles for serum IgE and IgG4, enhancing our understanding of microbial-clinical interactions in this disease.