Virus-inclusive single-cell RNA sequencing reveals the molecular signature of progression to severe dengue.

Dengue virus (DENV) infection can result in severe complications. However, the understanding of the molecular correlates of severity is limited, partly due to difficulties in defining the peripheral blood mononuclear cells (PBMCs) that contain DENV RNA in vivo. Accordingly, there are currently no biomarkers predictive of progression to severe dengue (SD). Bulk transcriptomics data are difficult to interpret because blood consists of multiple cell types that may react differently to infection. Here, we applied virus-inclusive single-cell RNA-seq approach (viscRNA-Seq) to profile transcriptomes of thousands of single PBMCs derived early in the course of disease from six dengue patients and four healthy controls and to characterize distinct leukocyte subtypes that harbor viral RNA (vRNA). Multiple IFN response genes, particularly MX2 in naive B cells and CD163 in CD14+ CD16+ monocytes, were up-regulated in a cell-specific manner before progression to SD. The majority of vRNA-containing cells in the blood of two patients who progressed to SD were naive IgM B cells expressing the CD69 and CXCR4 receptors and various antiviral genes, followed by monocytes. Bystander, non-vRNA-containing B cells also demonstrated immune activation, and IgG1 plasmablasts from two patients exhibited clonal expansions. Lastly, assembly of the DENV genome sequence revealed diversity at unexpected sites. This study presents a multifaceted molecular elucidation of natural dengue infection in humans with implications for any tissue and viral infection and proposes candidate biomarkers for prediction of SD.

Universal Screening for SARS-CoV-2 in Obstetric Care: Clinical Characteristics and Maternofetal Outcomes in a Latin American High-Complexity Unit.

The asymptomatic population's role in COVID-19 transmission poses challenges for control efforts. Pregnant women are susceptible to severe manifestations, increasing maternal and perinatal morbidity and mortality. This study describes the clinical characteristics, maternal and fetal outcomes, and our experience in universal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) screening of pregnant women admitted to a high-complexity obstetric unit in Latin America. Of 568 pregnant women tested for SARS-CoV-2, 23 obtained a positive result. Among these patients, 17% had symptoms at admission, and 0.2% reported an epidemiological link. Pregnant women with positive were associated with an increased risk of eclampsia (16.7% vs 4.9%, P = .014) and acute respiratory distress (16.7% vs 4.9%, P = .014). In this group, 4 patients developed maternal near misses, and no maternal deaths were noted. Two early perinatal deaths occurred in the positive SARS-CoV-2 test group (2, 9.5% vs 17, 4.1%, P = .235). The high prevalence of asymptomatic pregnant women with SARS-CoV-2 and the adverse outcomes for those infected during pregnancy highlights the importance of universal screening upon hospital admission. This approach streamlines risk management, and enhances service structure, resource allocation, care pathways, patient management, follow-up, and overall outcomes.

A 20-Gene Set Predictive of Progression to Severe Dengue.

There is a need to identify biomarkers predictive of severe dengue. Single-cohort transcriptomics has not yielded generalizable results or parsimonious, predictive gene sets. We analyzed blood samples of dengue patients from seven gene expression datasets (446 samples, five countries) using an integrated multi-cohort analysis framework and identified a 20-gene set that predicts progression to severe dengue. We validated the predictive power of this 20-gene set in three retrospective dengue datasets (84 samples, three countries) and a prospective Colombia cohort (34 patients), with an area under the receiver operating characteristic curve of 0.89, 100% sensitivity, and 76% specificity. The 20-gene dengue severity scores declined during the disease course, suggesting an infection-triggered host response. This 20-gene set is strongly associated with the progression to severe dengue and represents a predictive signature, generalizable across ages, host genetic factors, and virus strains, with potential implications for the development of a host response-based dengue prognostic assay.