The CD4 remission hypothesis postulates that decreased relapse and disease severity in IBD can be seen in HIV, and this is predominantly linked to CD4 T-helper cell depletion, as these CD4 cells (particularly T-helper 1 and 17 subsets) are crucial in facilitating a proinflammatory response through cytokine production and recruitment of macrophages, neutrophils, and other immune cells [19]. This evidence concerns the gene CD4 and inflammatory bowel disease.