High TNF-alpha and IL-8 levels predict low blood dendritic cell counts in primary cytomegalovirus infection

BackgroundIn vitro studies suggest that human cytomegalovirus (CMV) modulates the functions of dendritic cells (DCs). However, there are limited data on DC homeostasis in CMV-infected patients.ObjectivesThe aim of this study was to characterize circulating DCs and plasma cytokine levels in immunocompetent patients with primary, symptomatic CMV infections.Study designThe study population consisted of 14 patients suffering of CMV mononucleosis and 14 healthy volunteers (11 CMV-seropositive and 3 CMV-seronegative subjects) included as controls. Peripheral blood mononuclear cells were isolated and used to characterize DCs and to quantify CMV in the blood. Plasma levels of pro-inflammatory and anti-inflammatory cytokines were also measured.ResultsWe observed that patients who were developing CMV mononucleosis presented lower myeloid and plasmacytoid DC counts in peripheral blood compared with healthy controls. We also noted elevated levels of inflammatory mediators, of which tumor necrosis factor-α (TNF-α)—which activates DCs and endothelial cells—was the highest. Notably, the decrease in blood DCs correlated with high TNF-α and IL-8 levels by a hyperbolic function.ConclusionsOur results suggest that increased levels of inflammatory factors facilitate alterations in DC homeostasis during primary CMV infection, which may contribute to viral-induced modulation of host immunity.