KLF4 and infection: Post infection integrity of the alveolar-capillary barrier in myeloid KLF4 KO and KLF4 WT mice was assessed by determining the concentration of albumin in the bronchoalveolare lavage fluid (BALF) over that in plasma 24 hours after transnasal inoculation with PBS or 5x105 CFU NCTC 7978 pneumococci.