Polarization of chemokine receptor expression in human peripheral blood and bronchoalveolar T cells

In vitro experiments have demonstrated chemokine receptor (CCR) polarization amongst T helper subsets, with CCR3 and 4 preferentially expressed on Th2 (IL-4 secreting) cells, and CXCR3, CXCR6 and CCR5 on Th1 (IFN secreting) cells. We have investigated the CCR/cytokine pattern of individual peripheral blood T cells and bronchoalveolar lavage T cells in normals (n=8) and asthmatics (n=11) by flow cytometry. Cells were labeled for each CCR before stimulation with PMA/Calcium ionophore. Following fixation and permeabilization, intracellular staining for cytokine, and surface marker staining for CD3 was performed. The majority of T cells were not cytokine secreting. More BAL cells were cytokine secreting compared to blood (40.2%, 12.8% respectively) but the IFN:IL-4 secretion ratio was similar. In blood, significant polarization of CCR3, 4, 5 and CXCR3 expression according to described patterns was seen, for example 1.6% of Th1 cells expressed CCR3 compared to 25.4% of Th2 cells (p=0.0004) and for CCR4, 16.6% of Th1 cells expressed this receptor compared to 47.3% of Th2 cells (p=