KLF4 and Pleuritis: In line with the increased alveolar-capillary permeability, histological scoring of the lungs 24 hours after infection with 5x105 CFU NCTC 7978 pneumococci revealed a significant increase in perivascular edema and pleuritis formation and a tendency towards increased necrosis formation and area of pneumonia affected lung tissue in myeloid KLF4 KO mice in comparison with KLF4 WT mice (Figures 2F–I and Supplementary Figure S3).