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Abstract: FR-PO677

Gut Microbial Variation and Disease Status in IgA Nephropathy

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Saha, Manish K., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Collie, Mary Mcgowan, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Derebail, Vimal K., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Mottl, Amy K., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Roach, Jeffrey, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Bunch, Donna O., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Hogan, Susan L., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Andermann, Tessa, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Falk, Ronald, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Background

The pathogenesis of IgA nephropathy (IgAN) is ill-defined. Recent evidence suggests involvement of the gastrointestinal lymphoid tissue in association with the gut microbiome. We hypothesized that patients with IgAN have alterations in gut microbial composition compared to healthy controls (HC), especially during disease activity.

Methods

We performed a case-control study of adult patients with primary IgAN, and age-sex-gender-BMI matched healthy controls (HC). Patients with IgAN were sub-divided based on disease activity (active - UPCR > 1.5 g/g ; remission - UPCR < 1 g/g) and immunosuppressive therapy status (IS, on/off). DNA isolated from stool sample underwent 16S rRNA amplicon sequencing of the V4 variable region. The QIIME2 pipeline was used for analysis. Kruskal-Wallis and PERMANOVA tests were used to compare alpha- and beta-diversity between groups, respectively. ANCOM-II was used to assess taxonomic abundance between groups, and accounted for multiple testing.

Results

The gut microbiome composition of patients with IgAN in remission, off IS, showed significant differences from HC as measured by alpha-diversity index: a decrease in both Chao1 index (p=0.03) and observed features (p=0.02). No significant difference in beta diversity metric found. The genus Muribaculaceae was estimated to occur only in HC whereas Bacteroidales was estimated to occur only in patients in remission, off IS.
Although the gut microbiome composition of patients with active IgAN, off IS, showed no significant differences from HC as measured by diversity indices, there were significant alterations in the differential abundance of taxa among the different groups (Table1).

Conclusion

IgAN is associated with changes in the gut microbial composition. Megasphaera, a commensal of healthy gut, was present in HC and patients with IgAN in remission, off IS. Bacteriodales was present only in patients in remission status, off IS. Higher abundance of Enterobacteriaceae genus may reflect bacterial overgrowth due to IS.