Project description:Background: Dengue virus (DENV) infection often leads to acute illness lasting 2-7 days with severity ranging from dengue fever (DF) to hemorrhagic fever (DHF) and fatal dengue shock syndrome (DSS). The dynamic changes of host responses on the gene transcription level that accompany DENV infection and differences between DF and DHF cases have been poorly understood, particularly for South American population. Methodology/Principal Findings: Supported by a longitudinal active surveillance program for dengue transmission in Maracay, Venezuela, we conducted a prospective study to investigate host responses in dengue patients. Blood specimens and clinical information were collected on a daily basis from febrile cases confirmed with DENV infection from their first day of enrollment to early defervescence together with one convalescent sample. A total of 49 and 13 study participants were defined as DF and DHF cases respectively based on their clinical and hematological information. Using convalescent specimens as baseline, day-to-day gene expression was evaluated ex vivo in peripheral blood mononuclear cells of the study participants. Two waves of gene expression were detected: the first wave peaked at day 1 from the onset of fever (day 0) then declined at days 3-4; the second wave emerged from day 4 and peaked around day 5-6. Genes associated with innate immune process, including type I interferon signaling, cytokine-mediated signaling, chemotaxis, and antiviral responses, dominated the first wave; whereas genes involved in cell cycle processes, including cell division, mitosis, DNA replication, chromosome, and spindle organization dominated the second wave. Measureable genomic markers predicted early acute, late acute and convalescent phases with 91% accuracy. Gene signatures expressed in early acute phase predicted disease severity (DF vs DHF) with 96% accuracy. Conclusions/Significance: Our study established a dynamic pattern of detailed host immune responses to DENV infection and revealed genomic signatures valuable for diagnostics purposes. Total 64 subjects representing 51 DF (dengue fever) and 13 DHF (dengue hemorrhagic fever) cases were used to study gene expression during the course of dengue acute illness. Sample information regarding Patient No., Infecting serotype, fever status (fever days or defervescent (df) days), and disease severity (DF vs DHF) were provided. The date for a sample for gene chip hybridization and image scanning was marked as Scan date. Samples from study subjects were collected once a patient was enrolled. Over 200 samples were collected. Two genechip platforms were used, the HG-focus and HG-U133plus2. A total of 168 samples were assayed on the HG-focus platform, 2 were excluded for further analysis as they failed on quality control (i.e. VFP-0003_G7_DF, VFP-0029_G1_DF samples). A total of 101 samples were assayed on the HG-U133plus2 platform, 4 were excluded for further analysis as they failed on quality control (i.e. VFP_0186_G4_DF, VFP-0213_G3_DF, VFP_0213_G5_DF, VFP_0220_G3_DHF). Data generated by HG-focus platform were used to explore significantly expressed genes in individual Gs, phases, and for prediction analysis for disease phases. Whereas data generated by HG-U133plus2 were first used to assess the reproducibility of results generated by the HG-focus platform. Secondarily, they were used to perform prediction analysis for disease severity. Samples were grouped into stages (G) based on the timepoint when they were collected: G0=day0 (on the day of fever onset); G1=day 1 (one day after fever onset); G2=day2 (two days after fever onset)M-bM-^@M-&until G5; G6=day6-10 (6-10 days after fever onset); G7= convalescent time point (around day 28 after the first sample). Samples were also grouped into early acute (G0-G3), late acute (G4-G6) and convalescent phases (G7). References for the protocols; PMID 12803996 and 20078211

Project description:Background: Dengue virus (DENV) infection often leads to acute illness lasting 2-7 days with severity ranging from dengue fever (DF) to hemorrhagic fever (DHF) and fatal dengue shock syndrome (DSS). The dynamic changes of host responses on the gene transcription level that accompany DENV infection and differences between DF and DHF cases have been poorly understood, particularly for South American population. Methodology/Principal Findings: Supported by a longitudinal active surveillance program for dengue transmission in Maracay, Venezuela, we conducted a prospective study to investigate host responses in dengue patients. Blood specimens and clinical information were collected on a daily basis from febrile cases confirmed with DENV infection from their first day of enrollment to early defervescence together with one convalescent sample. A total of 49 and 13 study participants were defined as DF and DHF cases respectively based on their clinical and hematological information. Using convalescent specimens as baseline, day-to-day gene expression was evaluated ex vivo in peripheral blood mononuclear cells of the study participants. Two waves of gene expression were detected: the first wave peaked at day 1 from the onset of fever (day 0) then declined at days 3-4; the second wave emerged from day 4 and peaked around day 5-6. Genes associated with innate immune process, including type I interferon signaling, cytokine-mediated signaling, chemotaxis, and antiviral responses, dominated the first wave; whereas genes involved in cell cycle processes, including cell division, mitosis, DNA replication, chromosome, and spindle organization dominated the second wave. Measureable genomic markers predicted early acute, late acute and convalescent phases with 91% accuracy. Gene signatures expressed in early acute phase predicted disease severity (DF vs DHF) with 96% accuracy. Conclusions/Significance: Our study established a dynamic pattern of detailed host immune responses to DENV infection and revealed genomic signatures valuable for diagnostics purposes.

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Myeloid regulation signature persists after virus clearance in mild human primary dengue serotype 2 infection

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