Currently, several assays can confirm acute dengue infection at the point-of-care. However, none of these assays can predict the severity of the disease symptoms. A prognosis test that predicts the likelihood of a dengue patient to develop a severe form of the disease could permit more efficient patient triage and treatment. We hypothesise that mRNA expression of apoptosis and innate immune response-related genes will be differentially regulated during the early stages of dengue and might predict the clinical outcome. Aiming to identify biomarkers for dengue prognosis, we extracted mRNA from the peripheral blood mononuclear cells of mild and severe dengue patients during the febrile stage of the disease to measure the expression levels of selected genes by quantitative polymerase chain reaction. The selected candidate biomarkers were previously identified by our group as differentially expressed in microarray studies. We verified that the mRNA coding for CFD, MAGED1, PSMB9, PRDX4 and FCGR3B were differentially expressed between patients who developed clinical symptoms associated with the mild type of dengue and patients who showed clinical symptoms associated with severe dengue. We suggest that this gene expression panel could putatively serve as biomarkers for the clinical prognosis of dengue haemorrhagic fever.

Sindbis virus (SINV) induces inflammatory and vasoactive responses that are associated with rash and arthritis in human infections. The mechanisms underlying infection-associated microvasculopathy are still unknown. We investigated whether endothelial cells infected by SINV are differentially responsive to bradykinin (BK), a potent inducer of inflammatory edema in a broad range of infectious diseases. Human endothelial cells (HBMECs) infected with SINV presented an upregulation of bradykinin B2 receptors (BK2R) expression. Also, BK reduced SINV-induced apoptosis and enhanced virus replication in HBMECs in a way dependent on BK2R, PI3 kinase and ERK signaling. Strikingly, intracerebral infection of mice in the presence of a BK2R antagonist reduced the local viral load. Our data suggest that SINV infection renders human endothelial cells hypersensitive to BK, which increases host cell survival and viral replication. Ongoing studies may clarify if the deregulation of the kinin pathway contributes to infection-associated vasculopathies in life-threatening arbovirus infections.

Previous phylogenetic analyses indicated that the ZIKV epidemic was caused by the introduction of a single Asian genotype lineage into the Americas around late 2013, at least one year before its detection there 4 . An estimated 100 million people in the Americas are predicted to be at risk of acquiring ZIKV once the epidemic has reached its full extent 5 . However, little is known about the genetic diversity and transmission history of the virus in different regions in Brazil 6 . Reconstructing ZIKV spread from case reports alone is challenging because symptoms (typically fever, headache, joint pain, rashes, and conjunctivitis) overlap with those caused by co-circulating arthropod-borne viruses 7 and due to a lack of nationwide ZIKV-specific surveillance in Brazil before 2016. [Figure 1 around here]To address this we undertook a collaborative investigation of ZIKV molecular epidemiology in Brazil, including results from a mobile genomics laboratory that travelled through NE Brazil during June 2016 (the ZiBRA project; http://www.zibraproject.org). Of five regions of Brazil (Fig. 1a), the Northeast region (NE Brazil) has the most notified ZIKV cases (40% of Brazilian cases) and the most confirmed microcephaly cases (76% of Brazilian cases, to 31 Dec 2016 2 ), raising questions about why the region has been so severely affected 8 . Further, NE Brazil is the most populous region of Brazil with the potential for year-round ZIKV transmission 9 . With the support of the Brazilian Ministry of Health and other institutions (Acknowledgements), the ZiBRA lab screened 1330 samples (almost exclusively serum or blood) from patients residing in 82 municipalities across five federal states in NE Brazil ( Fig. 1 On average, ZIKV viremia persists for 10 days after infection; symptoms develop ~6 days after infection and can last 1-2 weeks 10 . In line with previous observations in Colombia 11 , we found that the RT-qPCR+ samples in NE Brazil were, on average, collected only two days after onset of symptoms. The median RT-qPCR cycle threshold (Ct) value of positive samples was correspondingly high, at 36 (Extended Data Fig. 1). For NE Brazil, the time series of RT-qPCR+ cases was positively correlated with the number of weekly-notified cases (Pearson's ρ=0.62; Fig. 1b).The ability of the mosquito vector Aedes aegypti to transmit ZIKV is determined by ecological factors that affect adult survival, viral replication, and infective periods 12 .To investigate the receptivity of each Brazilian region to ZIKV transmission, we used a measure of vector climatic suitability derived from monthly temperature, relative humidity, and precipitation data 9 . Using linear regression we find that, for each Brazilian region, there is a strong association between estimated climatic suitability and weekly notified cases (Figs. 1b,1c; adjusted R 2 >0.84, P<0.001; Extended Data Table 2). Similar to previous findings obtained for dengue virus outbreaks 13,14 , notified ZIKV cases lag climatic suitability by ~4 to 6 weeks in all regions, except NE Brazil,...

Class II Transactivator (CIITA) induces transcription of MHC class II genes. This protein can potentially be used to improve genetic immunotherapies by converting non-immune cells into cells capable of presenting antigens to CD4+ T helper cells. However, CIITA expression is complex, tightly controlled and remains unclear whether distinct non-immune cells differ in the regulation of this transcription factor. In the present study, we describe a strategy to develop gene delivery systems capable of promoting the efficient expression of CIITA in non-immune cell lines and in primary human cells in an ex vivo skin explant model. A DNA plasmid and a lentiviral vector were produced, both carrying the human CIITA DNA sequence in silico designed to avoid cis-regulatory elements, and genetically optimized for expression efficacy in human cells. Different human cell types undergoing CIITA overexpression presented high-level de novo expression of MHC II molecules, validating the delivery systems as suitable tools for the evaluation of CIITA potential as a molecular adjuvant for genetic immunizations. Further, we directly compared different non-immune cells according to exogenous CIITA transcriptional activity, protein expression levels and proteasome degradation. Here we show for the first time that distinct types of non-immune cells differentially regulate the transcription factor, and ultimately the cell surface expression of MHC II, through a cell type-specific control of CIITA proteasomal degradation. Our findings contribute to the understanding of the CIITA post-translational regulation by non-immune cells, which can greatly influence the use of this regulator of MHC II genes as a vaccine adjuvant.