CD4 and infection: The presence of a significant, positive correlation between the frequency of jejunal CD4+ T cells and the expression of villi surface epithelium TMPRSS2 possibly indicates that during infection, loss of jejunal CD4 T cells and increased proinflammatory IL-6 cytokines have a major impact on the loss of surface epithelial TMPRSS2 protein compared to TMPRSS2 expressed in crypts.