Host immunoglobulin G selectively identifies pathobionts in pediatric inflammatory bowel diseases.
Armstrong H, Alipour M, Valcheva R, Bording-Jorgensen M, Jovel J, Zaidi D, Shah P, Lou Y, Ebeling C, Mason AL, Lafleur D, Jerasi J, Wong GK, Madsen K, Carroll MW, Huynh HQ, Dieleman LA, Wine E
Microbiome. Jan 2019. doi: 10.1186/s40168-018-0604-3
Comment: Inflammatory bowel diseases (IBD) that include Crohn disease (CD) and ulcerative colitis (UC) display a reduced microbial diversity and elevated IgG levels in the lumen. Previous studies suggest that coating of intestinal bacteria with IgA can be used to identify pathogenic strains involved in the development of IBD. Authors hypothesized that bacteria more highly bound by IgG would display greater virulence and that identification of these invasive pathobiont strains will assist in understanding the mechanisms of intestinal immune activation and aberrant immune reactivity in IBD pathogenesis.
To characterize the composition of the intestinal microbiota of pediatric IBD and non-IBD control patients in luminal wash samples using Ilumina MiSeq sequencing of 16S rRNA gene library and shotgun metagenomics
Increased IgG binding to microorganisms collected from intestinal washes of the mucosal epithelium of pediatric IBD patients allows for selective identification of specific microorganisms that display pathobiont properties and, therefore, may be involved in driving or exacerbating IBD.
Binding of IgG favors different subsets of specific microbes in non-IBD, CD, or UC.
Increased IgG Coating Index (ICI) depicts increased invasive capacity, demonstrating in proof of principle that the described method of using ICI to identify bacteria that may be important in establishing and/or exacerbating the inflammation in IBD patients is valid.
Utilizing the techniques validated in this study to identify potential pathobionts, or microbes recognized by the patient IgG, in other disease settings could prove to be a powerful tool in tailored therapeutic options for a large number of patients.