Authors of an exploratory study used IgA sequencing to identify gut bacteria preferentially coated with IgA and galactose-deficient IgA1 (Gd-IgA1) in patients with IgA nephropathy (IgAN). Gd-IgA1–coated bacteria were significantly more abundant in patients with IgAN than in healthy controls, and the overall IgA-binding pattern differed between groups. Although the specific bacteria varied by individual, several taxa—including Ruminococcus torques, Ruminococcus gnavus, and members of the Ruminococcaceae and Lachnospiraceae families—were repeatedly coated with IgA and Gd-IgA1 in patients with IgAN.
The researchers also identified several mucin-degrading bacteria, including Akkermansia muciniphila and Bifidobacterium bifidum, raising the possibility that microbial glycosidases may contribute to IgA1 deglycosylation. In vitro testing showed increased IgA and Gd-IgA1 coating after B. bifidum was incubated with human IgA, while metagenomic analysis linked serum Gd-IgA1 levels with microbial carbohydrate-utilization pathways. The findings support a possible role for gut microbes in IgAN pathogenesis, but the study was small and exploratory, and larger cohorts are needed to validate whether these bacteria contribute directly to disease or could eventually represent therapeutic targets.
Reference: Lam DK, Ng NYY, Ting Cheung LP, et al. Gut Mucolytic Bacteria Is Associated with IgA Nephropathy. J Am Soc Nephrol. 2026 Jan 1;37(1):160-163. doi: 10.1681/ASN.0000000871.
