Effective triage of dengue patients early in the disease course for in- or out-patient management would be useful for optimal healthcare resource utilization while minimizing poor clinical outcome due to delayed intervention. Yet, early prognosis of severe dengue is hampered by the heterogeneity in clinical presentation and routine hematological and biochemical measurements in dengue patients that collectively correlates poorly with eventual clinical outcome. Herein, untargeted liquid-chromatography mass spectrometry metabolomics of serum from patients with dengue fever (DF) and dengue hemorrhagic fever (DHF) in the febrile phase (<96 h) was used to globally probe the serum metabolome to uncover early prognostic biomarkers of DHF. We identified 20 metabolites that are differentially enriched (p<0.05, fold change >1.5) in the serum, among which are two products of tryptophan metabolism–serotonin and kynurenine. Serotonin, involved in platelet aggregation and activation decreased significantly, whereas kynurenine, an immunomodulator, increased significantly in patients with DHF, consistent with thrombocytopenia and immunopathology in severe dengue. To sensitively and accurately evaluate serotonin levels as prognostic biomarkers, we implemented stable-isotope dilution mass spectrometry and used convalescence samples as their own controls. DHF serotonin was significantly 1.98 fold lower in febrile compared to convalescence phase, and significantly 1.76 fold lower compared to DF in the febrile phase of illness. Thus, serotonin alone provided good prognostic utility (Area Under Curve, AUC of serotonin = 0.8). Additionally, immune mediators associated with DHF may further increase the predictive ability than just serotonin alone. Nine cytokines, including IFN-γ, IL-1β, IL-4, IL-8, G-CSF, MIP-1β, FGF basic, TNFα and RANTES were significantly different between DF and DHF, among which IFN-γ ranked top by multivariate statistics. Combining serotonin and IFN-γ improved the prognosis performance (AUC = 0.92, sensitivity = 77.8%, specificity = 95.8%), suggesting this duplex panel as accurate metrics for the early prognosis of DHF.

TCR engagement leads to the transcriptional activation of cytokine genes and activation-induced cell death. Activated T cells undergo apoptosis upon expression and ligation of Fas ligand (FasL) to Fas/APO-1 (CD95) receptor. FasL expression is under the transcriptional regulation of multiple factors. The present study demonstrates that TCR-inducible FasL expression is also under the direct influence of the IFN regulatory factor (IRF) transcription factor family. Deletion and mutagenesis of a putative IRF-1 binding site in the FasL promoter results in deficient expression of FasL. EMSAs demonstrate specific FasL promoter binding by IRF-1 and IRF-2. Forced expression of either IRF-1 or IRF-2 leads to FasL promoter activation in T cells and FasL expression in heterologous cells. Finally, suppression of IRF-1 expression in T cells results in deficient TCR-induced FasL expression. These results confirm that the IRF family participates in the regulation of FasL gene expression.

The identification of serum biomarkers to improve the diagnosis and prognosis of hepatocellular carcinoma has been elusive to date. In this study, we took a mass spectroscopic approach to characterize metabolic features of the liver in hepatocellular carcinoma patients to discover more sensitive and specific biomarkers for diagnosis and progression. Global metabolic profiling of 50 pairs of matched liver tissue samples from hepatocellular carcinoma patients was performed. A series of 62 metabolites were found to be altered significantly in liver tumors; however, levels of acetylcarnitine correlated most strongly with tumor grade and could discriminate between hepatocellular carcinoma tumors and matched normal tissues. Post hoc analysis to evaluate serum diagnosis and progression potential further confirmed the diagnostic capability of serum acetylcarnitine. Finally, an external validation in an independent batch of 58 serum samples (18 hepatocellular carcinoma patients, 20 liver cirrhosis patients, and 20 healthy individuals) verified that serum acetylcarnitine was a meaningful biomarker reflecting hepatocellular carcinoma diagnosis and progression. These findings present a strong new candidate biomarker for hepatocellular carcinoma with potentially significant diagnostic and prognostic capabilities.

Influenza virus infection (IVI) and dengue virus infection (DVI) are major public health threats. Between IVI and DVI, clinical symptoms can be overlapping yet infection-specific, but host metabolome changes are not well-described. Untargeted metabolomics and targeted oxylipinomic analyses were performed on sera serially collected at three phases of infection from a prospective cohort study of adult subjects with either H3N2 influenza infection or dengue fever. Untargeted metabolomics identified 26 differential metabolites, and major perturbed pathways included purine metabolism, fatty acid biosynthesis and β-oxidation, tryptophan metabolism, phospholipid catabolism, and steroid hormone pathway. Alterations in eight oxylipins were associated with the early symptomatic phase of H3N2 flu infection, were mostly arachidonic acid-derived, and were enriched in the lipoxygenase pathway. There was significant overlap in metabolome profiles in both infections. However, differences specific to IVI and DVI were observed. DVI specifically attenuated metabolites including serotonin, bile acids and biliverdin. Additionally, metabolome changes were more persistent in IVI in which metabolites such as hypoxanthine, inosine, and xanthine of the purine metabolism pathway remained significantly elevated at 21-27 days after fever onset. This study revealed the dynamic metabolome changes in IVI subjects and provided biochemical insights on host physiological similarities and differences between IVI and DVI.