CXCR2 and pneumonia: To investigate the role of haematopoietic and non-haematopoietic CXCR2 in the lung, neutrophil recruitment and bacterial clearance were analyzed in global (CXCR2−/−) as well as endothelial (CXCR2fl/flCdh5Cre+) and epithelial (CXCR2fl/flShhCre+) cell type-specific conditional KO mice in a murine model of K. pneumoniae-induced pneumonia.