Interleukin‐4 promotes human CD8 + T cell expression of CCR7

Summary Despite strong evidence supporting a pathway of human T cell differentiation characterized by changes in the expression of CCR7, CD28, CD27 and CD62L, few studies have addressed the mechanisms of pathway regulation. Cutaneous lymphocyte‐associated antigen (CLA)‐positive skin‐homing CD8 + T cells expressed significantly elevated levels of activation markers compared with CLA −  CD8 + T cells in individuals ( n  = 27) with cutaneous atopic disease. Despite such an activated phenotype, CLA + T cells expressed significantly higher levels of CCR7 than a CLA − T cell subset. Interleukin (IL)‐4 was found to dramatically promote CCR7 expression by antigen‐specific CD8 + cells. Furthermore, skin‐homing CD8 + T cells from individuals with severe disease produced significantly less IL‐10 than those derived from mildly affected atopic subjects. Thus in a T‐helper 2 dominated disease, tissue‐specific CD8 + T cells show altered CCR7 expression and cytokine production, which may contribute to continued lymph node homing, antigen presentation and disease. IL‐4 promotes expression of CCR7, a marker linked to existing models of CD8 + T cell differentiation.