Whole blood gene expression in Vietnamese dengue patients

Dengue is a pan-tropic public health problem. In children, dengue shock syndrome (DSS) is the most common life-threatening complication. Predicting patients who may develop DSS may improve triage and treatment. To this end, we conducted a nested case-control comparison of the early host-transcriptional features in 24 DSS patients and 56 sex-, age-, virus serotype-matched uncomplicated dengue patients. In the first instance we defined the “early dengue” profile. The transcriptional signature in acute versus convalescent samples (≤72hrs post illness-onset) was defined by an over-abundance of interferon-inducible transcripts (31% of the 551 over-abundant transcripts), and canonical gene ontology terms that included response to virus, immune response, innate immune response and inflammatory response. Pathway and network analysis identified STAT1, STAT2, STAT3, IRF7, IRF9, IRF1, CEBPB and SP1 as key transcriptional factors mediating the early response. Strikingly, the only differences in the transcriptional signatures of early DSS and uncomplicated dengue cases was the greater abundance of several neutrophil-associated transcripts in patients who progressed to DSS, a finding supported by higher plasma concentrations of several canonical proteins associated with neutrophil-degranulation (BPI, ELA2, DEF1A). Elevated levels of neutrophil-associated transcripts were independent of the neutrophil count and also the genotype of the infecting virus, as genome-length sequences of DENV-1 (n=15) and DENV-2 (n=3) viruses sampled from DSS patients were phylogenetically indistinguishable from those sampled from uncomplicated dengue patients (32 DENV-1 and 9 DENV-2). Collectively, these data suggest an hitherto unrecognised association between neutrophil activation, pathogenesis and the development of DSS and point to future strategies for guiding prognosis. 112 patients: 80 with uncomplicated dengue, 32 with dengue shock syndrome