Spondyloarthritis is the most common extraintestinal manifestation in patients with inflammatory bowel disease (IBD), but the underlying pathogenesis of the link between the two conditions remains unknown. Researchers led by Randy Longman, M.D., Ph.D., of the Jill Roberts Center for Inflammatory Bowel Disease at Weill Cornell Medicine, recently reported that IBD-associated spondyloarthritis is associated with a unique immunogenic microbial signature.
Because “IBD involves a dysregulated intestinal immune response to luminal microbial antigens, and the abundance of particular microbial clades has been correlated to other arthropathies,” the investigators wrote, patients with IBD-associated spondyloarthritis may have a distinct population of gut microbiota, they hypothesized.
To test this idea, investigators characterized the fecal microbiome of 59 patients with IBD using 16S rRNA sequence analysis, and assessed inflammatory joint disease activity using two documented scoring systems. Based on guidelines set forth by the Assessment of Spondyloarthritis International Society, the investigators determined that 34 patients had spondyloarthritis. Measures of inflammatory joint disease activity in patients with spondyloarthritis were significantly higher than in Crohn’s disease patients without spondyloarthritis. Fecal microbiome genetic analyses revealed more significant expansion of Enterobacteriaceae and enrichment of Escherichia coli/Shigella in these patients, when compared with Crohn’s disease patients without spondyloarthritis. Murine studies demonstrated that these patient-derived E. coli isolates were immunologically active.
“Our findings reveal that the intestinal microbiota of patients with IBD–spondyloarthritis is selectively enriched in immunologically-relevant E. coli,” the authors wrote.
Further studies may reveal potential diagnostic and therapeutic targets, they said.
These findings were presented at the 2015 Advances in Inflammatory Bowel Diseases, Crohn’s & Colitis Foundation’s Clinical & Research Conference, held in Orlando, and were published in the March 2016 supplement of Inflammatory Bowel Diseases.