NOD2 and inflammatory bowel disease: Some emerging evidence supports a causal role of gut dysbiosis in IBD, since transfer of disease-associated microbiota triggers CD-like inflammation in genetically susceptible GF recipient mice.163 Microbiota from IBD patients transplanted to GF mice likewise induces imbalances in intestinal Th17 and RORgt+ regulatory T cells.164 More strikingly, one single pathobiont, Mucispirillum schaedleri, was demonstrated to be sufficient to trigger a Th1 cell-driven intestinal inflammation in mice deficient in both NOD2 and CYBB.165 Similarly, ectopic colonization of oral Klebsiella spp.