CD4 and peptic ulcer disease: In a study on the relationship between the expression of CD4 and FOXP3 in patients with peptic ulcer, Bagheri et al. showed that the number of CD4+ T cells positively correlated with CagA, whereas FOXP3+ T cells as well as the expressions of IL-10, TGF-β1, FOXP3, and INF-γ were closely associated with the density of HP [94].