VCAM1 and endothelial dysfunction: PD-1 expression in CD8+ T-cells shows a strong positive correlation with plasma leakage grade, markers of endothelial dysfunction and with the dengue severity-related markers (ferritin and CXCL-10/IP-10) at both time points (Fig. 3h shown for TP2; Fig. 3i, j: angiopoietin-2 and VCAM-1, shown for TP1 and TP2).