The human platelet transcriptome is altered during dengue infection. Platelets were isolated from patients with confirmed dengue infection or matched healthy control subjects. Purified platelets were isolated as described in “Methods.” (A) Heat map of significantly differentially expressed (adjusted P < .05) transcripts in dengue-infected patients (n = 3) and healthy control subjects (n = 3). Red indicates significantly enriched transcripts, and blue indicates significantly repressed transcripts. (B) Scatter plot with significantly enriched (red) and repressed (blue) transcripts. IFITM3 is indicated (enlarged dot). (C) Representative Integrative Genomics Viewer browser image of IFITM3 mRNA expression in a dengue-infected patient (bottom) or healthy control subject (top). The vertical axis represents the relative amount of mRNA, and the horizontal axis shows the introns (thin lines) and exons (thick lines). (D-G) Whole blood samples were drawn from patients with mild dengue infection (mild, n = 4), dengue-infected patients with warning signs (WS) or severe infection (Sev) (WS + Sev, n = 7), or healthy matched control subjects (n = 3). (D) Plasma levels of IFNα in healthy subjects (healthy) and in patients with mild dengue infection or severe dengue with WS. (E-F) Immunoblot and densitometric quantification of IFITM3 and β-actin expression in platelets isolated from healthy subjects (n = 3) and dengue-infected patients (n = 11) with mild, WS, or severe infection. The immunoblot results shown from healthy control subjects are representative of >30 individuals. (G) Plasma IFNα levels were plotted against IFITM3 protein expression in platelets from patients with dengue. Linear regression (± 95% confidence interval) was traced according to the distribution of the dots.