A population of CD4+CD8+ double-positive T cells associated with risk of plasma leakage in dengue viral infection

According to the WHO 2009 classification, dengue with warning signs (D+W) is at the risk of developing severe form of dengue disease. One of the most important warning signs is plasma leakage, which is a serious complication associated with higher morbidity and mortality. We report that the frequency of CD4+CD8+ double-positive (DP) T cells is significantly increased in patients at risk of developing plasma leakage. Transcriptomic analysis demonstrated that CD4+CD8+ DP cells were distinct from CD4+ Single Positive (SP) T cells, but co-clustered with CD8+ SP cells indicating a largely similar transcriptional profile. 20 significant differentially expressed (DE) genes were identified between CD4+CD8+ DP and CD8+ SP cells. These genes encode OX40 and CCR4 (TNFRSF4 and CCR4), as well as other molecules associated with cell signaling on the cell surface (NT5E, MXRA8, PTPRK). While 5 significant DE genes were identified, the profile of gene expression in CD4+CD8+ DP cells was mostly similar between patients with and without warning signs of plasma leakage, implying a role of CD4+CD8+ DP cells in plasma leakage through a quantitative increase rather than functional alteration. The differentially expressed genes identified could have diagnostic utility, perhaps as PCR-based diagnostic markers. Overall design: RNA-sequencing of sorted T cells from 55 dengue patients with warning signs of plasma leakage (D+W), and 33 dengue patients without warning signs of plasma leakage (D-W)