Differential ex vivo and in vivo endotoxin tolerance kinetics following human endotoxemia*

Abstract

While ex vivo lipopolysaccharide tolerance quickly resolves, in vivo lipopolysaccharide tolerance persists for at least 2 wks. These findings strengthen the notion that the in vivo response to lipopolysaccharide is mediated by tissue-resident macrophages and that ex vivo stimulation does not accurately reflect the in vivo innate immune response. Intervention studies utilizing the human endotoxemia model should be performed using parallel groups rather than a crossover design.