This study shifts the focus of gut microbiome research from merely the presence of bacteria to the roles of their vesicles and how these interactions impact immune responses.

The findings suggest that targeting IgA-coated BEVs could lead to new therapeutic strategies for managing ulcerative colitis, including neutralizing antibodies or blocking CD89.

The prevalence of ulcerative colitis is increasing, particularly in industrialized nations, where many patients experience treatment resistance or relapses.

Researchers found high levels of IgA-coated BEVs in the colonic samples of ulcerative colitis patients compared to healthy individuals, alongside increased CD89-positive immune cells in inflamed gut mucosa.

BEVs are tiny sacs produced by gut bacteria that contain pro-inflammatory substances such as lipopolysaccharide (LPS), proteins, and DNA fragments.

IgA-coated BEVs bind to the CD89 receptor on immune cells, triggering potent inflammatory responses that may be central to chronic inflammation in ulcerative colitis.

A new international study led by researchers from the Medical University of Graz and the University of Graz has identified a significant contributor to chronic inflammation in ulcerative colitis.

More than 5 million people globally suffer from ulcerative colitis, a chronic inflammation of the colon with unclear causes.

The study, published in Nature Communications, reveals that bacterial extracellular vesicles (BEVs) coated with immunoglobulin A (IgA) play a critical role in promoting inflammation in the colon.

In mouse models with a human CD89 receptor, IgA BEVs exacerbated gut inflammation, suggesting that the combination of bacterial vesicles and IgA is crucial for inflammation activation.