In later phases of the allergic response, other inflammatory cells (basophils, eosinophils, and CD4+ T cells) infiltrate the allergy site when allergy mediators such as histamine, tumor necrosis factor alpha (TNFA), leukotriene C4 and prostaglandin D2 stimulate endothelial cells to express adhesion molecules. Here, CD4 is linked to Allergy.