However, if the inflammatory response is severe and prolonged, hepatic necrosis may eventually lead to extensive loss of parenchyma and irreversible tissue fibrosis. Neutrophils are capable of migrating rapidly to foci of infection or inflammation. Infiltration and contact with inflammatory mediators can reprogram cells to alter effector responses. Chakravarti et al. 17 recently described a subset of human blood neutrophils that became long-lived, expressed human leukocyte antigen DR, CD80, and CD49d de novo, and alternatively produced leukotrienes, superoxide anions, and cytokines upon exposure MK0683 to granulocyte-macrophage colony-stimulating factor, tumor necrosis factor α, and

IL-4. Thus, the microenvironment can reprogram cells that traditionally have been thought to be terminally differentiated, and this can affect disease progression. Here, we show that IL-4 was necessary for the full development of hepatic necrosis in infected IL-10 KO mice, and CD4+ T cells, a proportion of which were activated within GALT, constituted a major source of IL-4 in the liver. Furthermore, our data Trametinib concentration indicated that neutrophils played a critical role in the progression from

hepatocellular injury to necrosis. The accumulation of neutrophils was inhibited in the absence of IL-4 concomitantly with altered expression of key activation molecules, highlighting a role for this cytokine in the management of neutrophil function. These data define a critical balance between IL-10 and IL-4 in the hepatic response to enteric infection and suggest a role for CD4+ T cells and IL-4 in regulation of neutrophil activity Branched chain aminotransferase during hepatic injury. Our results also demonstrated the utility of this in vivo system not only for the investigation of the specific roles of IL-10 and IL-4 in the hepatic response to infection with this parasite but also for broader

inquiry into the coordination of enteric and hepatic immune mechanisms. In several experimental models of liver injury, IL-4 has been shown alternatively to be protective or deleterious. For example, IL-4 protects mice from damage induced by ischemia/reperfusion, but it promotes hepatitis after concanavalin-A injection. 18, 19 Although IL-4 and neutrophils are known to participate in the pathogenesis of certain liver diseases, very little is established about how IL-4 directly or indirectly influences neutrophil activity. Interestingly, Huang et al. 20 recently reported that IL-4 stimulated the expression of chemokine (C-X-C motif) ligand 8, CD62E, vascular endothelial growth factor, and inducible nitric oxide synthase by equine pulmonary artery endothelial cells, resulting in neutrophil migration in vitro. In our studies, the capacity to produce IL-4 influenced expression of neutrophil adhesion molecules and sequestration in the liver.