Patients With Inflammatory Bowel Disease Show IgG Immune Responses Towards Specific Intestinal Bacterial Genera

• DOI: 10.3389/fimmu.2022.842911
• Publication Date: 2022-05-25T05:16:42Z
• Authors: Arno R. Bourgonje; Geesje Roo-Brand; Paola Lisotto; Mehdi Sadaghian S...; Rosanne D. Reitsema; Marcus C. de Goffau; Klaas Nico Faber; Gerard Dijkstra; Hermie J. M. Harmsen
• Keywords: Lachnospiraceae; Ruminococcus; Roseburia

Introduction Inflammatory bowel disease (IBD) is characterized by a disturbed gut microbiota composition. Patients with IBD have both elevated mucosal and serum levels of IgG-antibodies directed against bacterial antigens, including flagellins. In this study, we aimed to determine which intestinal bacteria the humoral immune response in patients IBD. Methods Fecal samples were collected from ( n =55) age- sex-matched healthy controls =55). incubated autologous IgG-coated fractions isolated magnetic-activated cell sorting (MACS) its efficiency was assessed flow cytometry. The composition untreated fecal determined 16S rRNA-gene Illumina sequencing. Results significantly lower microbial diversity compared microbiome. Both controls, IgG responses primarily Streptococcus , Lactobacillus Lactococcus Enterococcus Veillonella Enterobacteriaceae as well specific Lachnospiraceae bacteria, Coprococcus Dorea (all P <0.001), Ruminococcus gnavus -like <0.05). contrast, serological typical commensal, anaerobic colonic species rather low, e.g. members Roseburia Blautia Faecalibacterium Bacteroides . showed more IgG-coating No differences observed between Crohn’s ulcerative colitis, active or non-active disease, nor different locations. Conclusion specifically targeted at distinct genera that are typically associated small microbiota, whereas colonic-type commensals lower, particularly case for These findings may be indicative strong immunological exposure potentially pathogenic concordance relative tolerance commensal bacteria.