Discovery and validation of circulating miRNAs for the clinical prognosis of severe dengue

Background: dengue is a potentially life-threatening viral infection. Early prognostic markers of severe complications may improve case management and reduce dengue-related mortalities. This study aimed to identify circulating microRNAs (miRNAs) as biomarkers for predicting severe dengue. Methods: Serum samples from dengue-infected patients were collected on the first day of admission. Patients were followed up for 14 days after admission to determine the final diagnosis. Participants were divided into non-severe and severe dengue, as defined by WHO 2009 criteria. Circulating microtranscriptome analysis was performed using the NanoString miRNA Expression Assay. The expression level of candidate miRNAs were then validated by quantitative reverse transcription-PCR (qRT-PCR) method. Findings: The discovery cohort (N=19) lead to the identification of 37 differentially expressed miRNAs between the two groups. Six miRNAs (miR122-5p, miR1246, miR1303, miR574-5p, miR30d-5p, and miR424-5p) were selected and further validated in the larger cohort (N=135). The qRT-PCR analysis confirmed that the six miRNAs expression levels were significantly higher in the severe dengue group compared to the non-severe group. Based on receiver operating characteristic (ROC) analysis, miR574-5p and miR1246 displayed the highest diagnostic performance in discriminating between severe from non-severe dengue (AROC curve =0·83). Additionally, miR574-5p and miR1246 had high sensitivity and high negative predictive value for detecting severe dengue. Multivariate analysis suggested that serum miR574-5p was an independent predictor of severe dengue (odds ratio 3·30, 95% CI 1·81-6·04; p<0·001). Interpretation: Circulating miRNAs, especially miR-574-5p and miR-1246, could be promising diagnostic and prognostic biomarkers for severe dengue. A total of 19 serum samples were selected to investigate the expression profile of 798 human miRNAs using the nCounter1Human v3 miRNA Expression Assays (NanoString Technologies, Seattle, USA). The patients were divided into two groups based on their final diagnosis, including non-severe (N=11) and severe dengue groups (N=8).