Lipopolysaccharide levels are elevated in dengue virus infected patients and correlate with disease severity.

BACKGROUND Although in the majority of cases dengue virus (DENV) infection results in a self-limiting febrile disease, it can cause severe plasma leakage in a minority of patients. The appearance of plasma leakage indicates an increased permeability of the vascular wall. In this study we investigated if DENV infection can lead to leakage of lipopolysaccharide (LPS) from the intestine into the blood of the patient, indicative of an increased permeability of the intestinal mucosal barrier. OBJECTIVES The aim of this study was to investigate if LPS levels were elevated in DENV infected patients and if these levels correlated with disease severity. STUDY DESIGN LPS levels in the blood of DENV infected children were determined using the Limulus Amebocyte Lysate assay. To determine disease severity we used the 1997-WHO criteria, the expert physician's judgement and a score that focused on plasma leakage in particular. Furthermore, the modulatory factors LPS binding protein (LBP) and sCD14, as well as the immune activation marker neopterin were determined. RESULTS We showed significantly elevated LPS levels in plasma of DENV infected children compared to healthy controls. The plasma leakage severity score had the strongest correlation with levels of LPS. LBP, sCD14 and neopterin were elevated compared to healthy controls. CONCLUSION In this study we show evidence of elevated LPS levels during DENV infection. Moreover, a correlation between LPS levels and disease severity was found, especially when disease severity was determined in terms of plasma leakage.