CD4 and inflammatory bowel disease: However, recent findings implicate aberrant innate immune responses mediated through innate lymphoid cells, a novel family of effector lymphocytes in IBD that produce IBD-relevant cytokines in response to the gut microbiome, as well as involvement of the type 17 CD4+ T-helper T-cell (Th17)-IL-23 axis as contributing to the pathogenesis of CD [40, 41].