Association of dengue virus‐specific polyfunctional T‐cell responses with clinical disease severity in acute dengue infection

INTRODUCTION: Although the role of dengue virus (DENV)‐specific T cells in the pathogenesis of acute dengue infection is emerging, the functionality of virus‐specific T cells associated with milder clinical disease has not been well studied. We sought to investigate how the functionality of DENV–NS3 and DENV–NS5 protein‐specific T cells differ in patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). METHODS: Using intracellular cytokine assays, we assessed the production of interferon γ (IFNγ), tumor necrosis factor‐α (TNF‐α), macrophage inflammatory protein‐1β (MIP‐1β), and CD107a expression in adult patients with acute DF (n = 21) and DHF (n = 22). RESULTS: Quadruple cytokine‐producing, polyfunctional DENV–NS3‐ and DENV–NS5‐specific T cells were more frequent in those with DF when compared to those with DHF. While DENV–NS3‐ and DENV–NS5‐specific T cells in patients with DF expressed IFNγ > TNF‐α > MIP‐β > CD107a, T cells of those with DHF predominantly expressed CD107a > MIP‐1β > IFNγ > TNF‐α. Overall production of IFNγ or TNF‐α by DENV–NS3‐ and DENV–NS5‐specific T cells was significantly higher in patients with DF. The majority of NS3‐specific T cells in patients with DF (78.6%) and DHF (68.9%) were single‐cytokine producers; 76.6% of DENV–NS5‐specific T cells in those with DF and 77.1% of those with DHF, produced only a single cytokine. However, no significant association was found with polyfunctional T‐cell responses and the degree of viraemia. CONCLUSIONS: Our results suggest that the functional phenotype of DENV‐specific T cells are likely to associate with clinical disease severity.