Endotoxin tolerance drives neutrophil to infectious site

The objective of this randomized animal study and laboratory investigation was to investigate whether lipopolysaccharide tolerance redirects neutrophil migration between organs. Male BALB/c mice received subcutaneous injections of lipopolysaccharide (1 mg/kg) for 5 days, followed by cecal ligation and puncture (CLP). Cytokines and adhesion molecules were measured after tolerance and CLP challenge. Increased numbers of neutrophils were observed in the peritoneal cavity of tolerant mice, which was associated with increased levels of adhesion molecules and chemokines. In contrast, nontolerant mice accumulated higher numbers of neutrophils in the lungs compared with those in the peritoneal cavity. Neutrophil function accessed by hydrogen peroxide production from neutrophils recovered from peritoneal cavity showed that tolerance increased the capacity to produce hydrogen peroxide. Mortality was reduced in tolerant animals. This study demonstrated that tolerance reduces leukocyte accumulation in the lung after CLP by redirecting neutrophils to the site of infection.