Increased antibody response toward Lachnospiraceae flagellin is associated with subsequent risk for Crohn disease<\/p>\n<\/h3>\n
By Elana Gotkine HealthDay Reporter<\/b>
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TUESDAY, Jan. 13, 2026 (HealthDay News) — For healthy first-degree relatives (FDRs) of patients with Crohn disease (CD), increased antibody response toward Lachnospiraceae <\/em>flagellin is associated with the subsequent risk for CD, according to a study published online Jan. 11 in Clinical Gastroenterology and Hepatology<\/em>.<\/p>\n Richard Y. Wu, M.D., Ph.D., from the University of Toronto, and colleagues characterized the antimicrobial antibody responses before CD diagnosis in healthy FDRs of patients with CD. A total of 77 FDRs who later developed CD were matched by age, sex, follow-up duration, and geographic location with 304 healthy FDRs. Sera were probed for antimicrobial reactivity using a microbiota antigen microarray and a flagellin peptide cytometric bead array.<\/p>\n The researchers found significant associations for 19 out of 49 immunoglobulin G (IgG) antimicrobial antibody responses with the risk for CD; these antibodies were reactive to the Lachnospiraceae <\/em>family, especially Roseburia<\/em>-derived flagellins. Positive correlations were seen for five antibodies with fecal calprotectin (FCP), while three were positively associated with lactulose-to-mannitol ratio (LMR). Significant amino acid sequence homology was shared by these IgG-seroreactive flagellins, characterized by a conserved “hinge peptide” within D0-D1 domains of the amino-terminus. Independent of LMR and FCP, elevated IgG seroreactivity to the hinge peptide was associated with the future risk for CD.<\/p>\n “We found that this immune response is driven by a conserved domain of the flagellin protein. This raises the potential for designing a flagellin-directed vaccine in selected high-risk individuals for prevention of disease. Further validation and mechanistic studies are underway,” coauthor Sun-Ho Lee, M.D., also from the University of Toronto, said in a statement.<\/p>\n Three authors disclosed ties to the biopharmaceutical industry.<\/p>\n Abstract\/Full Text (subscription or payment may be required)<\/a><\/p>\n