Chronic viral hepatitis and iron affect the plasma levels of LIGHT--a new member of the TNF superfamily in uraemic haemodialyzed patients

LIGHT (lymphotoxin-like inducible protein that competes with glycoprotein D for binding herpesvirus entry mediator on T cells) is a recently identified of the tumor necrosis factor alpha (TNF-alpha) ligand superfamily. We wanted to establish whether the presence of chronic viral hepatitis could be implicated in enhanced inflammation as well as the elevation of plasma LIGHT levels in haemodialyzed (HD) patients. The plasma levels of LIGHT, high sensitivity C-reactive protein (hs CRP) and TNF-alpha were measured in HD patients with hepatitis in comparison to subjects without hepatitis and to healthy volunteers. The values of hs CRP and TNF-alpha were significantly elevated in HD patients when compared to the controls. TNF-alpha levels were significantly higher in the hepatitis-positive relative to the hepatitis-negative group (p <0.01). LIGHT levels were significantly decreased in hepatitis-negative patients as compared to controls (p <0.001) and hepatitis-positive group (p < 0.01). Both LIGHT and TNF-alpha were directly associated with the presence of hepatitis. Multiple stepwise regression analysis identified increased iron levels as the only independent variable significantly associated with increased LIGHT (beta=0.475, p=0.003). These results suggest the presence of chronic viral hepatitis and iron levels are novel determinants of the increased LIGHT in the plasma of HD patients.