CCR2 and acute respiratory distress syndrome: Further analysis by flow cytometry and ELISA indicated that the reduced lung inflammation in the Ly6C(+) circulating monocyte-depleted mice was accompanied with lower expression of CCR2 in CD11b(+) myeloid cells (Fig. 9d, right panel) and CXCL15 in BAL and lungs (Fig. 9e) (p < 0.05 v.s. the Group), further indicating the important function of monocyte chemotaxis in the progression of ALI.