CD8A and Crohn ileitis: It has been shown that a CD8+ T cell population lacking CD44 but expressing CD103 produced transforming growth factor beta (TGF-β), inhibit CD4+ proliferation in vitro, and attenuate adoptively transferred ileitis in vivo, most likely by counteracting the proinflammatory role of the CD44high subset of T cells.[33] Therefore, these CD8+ Tregs exhibit a naive T cell phenotype (CD8+CD103+CD44lowCD62Lhigh), as shown in Figure 1.