The IgA-biome revised: A meta-analysis of IgA-microbe interactions in gut health and disease

Immunoglobulin A (IgA) plays a central role in shaping gut microbial communities and maintaining mucosal homeostasis. Here, we present the first meta-analysis of the human gut IgA-microbiome covering gut health and disease using published data from 1,033 samples. Across cohorts, patients consistently exhibited an increased proportion of IgA-coated bacteria relative to healthy individuals, accompanied by reduced microbial diversity. IgA-coated fractions were enriched for a conserved subset of bacterial taxa present across health and disease. Together, these findings suggest structured IgA targeting in the human gut, preferentially focusing on taxa with traits that support success in the dynamic gut environment, with disease marked by a shift toward microbial features associated with inflammation.