Chemotaxis of human CD4+ eosinophils

We reviewed the biological functions of CD4+ eosinophils, which are observed in peripheral blood, sputum and bronchoalveolar lavage fluid of various diseases. We have shown that CD4 molecules on human eosinophils are induced by tumor necrosis factor-alpha (TNF-alpha) stimulation. Interleukin-16 (IL-16) has been reported to bind a natural soluble ligand for the CD4 molecule. We reported that TNF-alpha-stimulated eosinophils migrate in a time- and dose-dependent manner against IL-16. Theophylline and dexamethasone significantly inhibited CD4 expression. Theophylline inhibited CD4+ eosinophil chemotaxis, but dexamethasone did not. Theophylline may prevent airway inflammation by downregulating the expression of CD4 molecule and CD4+ eosinophil migration. However, dexamethasone may inhibit airway inflammation through the downregulation of CD4 expression.