Increase of Plasma TNF- α Is Associated with Decreased Levels of Blood Platelets in Clinical Dengue Infection.

Dengue virus (DENV) infection has become an increasingly common concern in tropical and subtropical regions. It has protean manifestations ranging from febrile phase to severe life-threatening illness. In this study, we estimated Th1 and Th2 cytokines and correlated the levels with dengue severity along with certain hematological and biochemical parameters. We also studied the seroprevalence of dengue between October and December 2017 at the Government Theni Medical College, India. Individuals with dengue fever (DF) were positive for either IgM or IgG, or both. The biochemical and hematological parameters along with plasma tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), granulocyte monocyte-colony stimulating factor (GM-CSF), interleukin (IL)-13, IL-12p70, IL-10, IL-5, IL-4, and IL-2 cytokines were estimated. The prevalence of DF was 42.9% during the study period. IL-2, TNF-alpha, IL-4, and IL-10 levels were significantly elevated (p < 0.005) in patients with secondary DENV infection, whereas the level of IL-13 remained unaltered during both primary and secondary infections. No statistically significant difference was noticed with IL-12p70, IL-5, IFN-gamma, and GM-CSF between the healthy controls and the primary and secondary DENV-infected groups. Increase of 1 unit of TNF-alpha was associated with a decrease of 160 units of blood platelets. Together, the study suggests that TNF-alpha could play a key role in the pathogenesis of dengue, and despite the decrease in platelet levels, it remains to be seen whether any other inflammatory cells regulate the levels of TNF-alpha in DENV infection.