CXCR2 and acute respiratory distress syndrome: Strikingly, the LPS-induced ARDS-associated increase in the percentage and numbers of the CXCR2+ neutrophils in the lungs was markedly reduced in LPS-treated CCR2gfp/gfp KI/KO mice (Figures 5C, D) when compared to the WT mice (Figures 4D, E).