EVALDO STANISLAU AFFONSO DE ARAUJO
Projetos de Pesquisa
Unidades Organizacionais
Instituto Central, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/47 - Laboratório de Hepatologia por Vírus, Hospital das Clínicas, Faculdade de Medicina
LIM/47 - Laboratório de Hepatologia por Vírus, Hospital das Clínicas, Faculdade de Medicina
3 resultados
Resultados de Busca
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- CD8+T Lymphocyte Expansion, Proliferation and Activation in Dengue Fever(2015) MATOS, Andreia Manso de; CARVALHO, Karina Inacio; ROSA, Daniela Santoro; VILLAS-BOAS, Lucy Santos; SILVA, Wanessa Cardoso da; RODRIGUES, Celia Luiza de Lima; OLIVEIRA, Olimpia Massae Nakasone Peel Furtado; LEVI, Jose Eduardo; ARAUJO, Evaldo Stanislau Affonso; PANNUTI, Claudio Sergio; LUNA, Expedito Jose Albuquerque; KALLAS, Esper GeorgeDengue fever induces a robust immune response, including massive T cell activation. The level of T cell activation may, however, be associated with more severe disease. In this study, we explored the level of CD8+ T lymphocyte activation in the first six days after onset of symptoms during a DENV2 outbreak in early 2010 on the coast of Sao Paulo State, Brazil. Using flow cytometry we detected a progressive increase in the percentage of CD8+ T cells in 74 dengue fever cases. Peripheral blood mononuclear cells from 30 cases were thawed and evaluated using expanded phenotyping. The expansion of the CD8+ T cells was coupled with increased Ki67 expression. Cell activation was observed later in the course of disease, as determined by the expression of the activation markers CD38 and HLA-DR. This increased CD8+ T lymphocyte activation was observed in all memory subsets, but was more pronounced in the effector memory subset, as defined by higher CD38 expression. Our results show that most CD8+ T cell subsets are expanded during DENV2 infection and that the effector memory subset is the predominantly affected sub population.
- Inter- and Intra-Host Viral Diversity in a Large Seasonal DENV2 Outbreak(2013) ROMANO, Camila Malta; LAUCK, Michael; SALVADOR, Felipe S.; LIMA, Celia Rodrigues; VILLAS-BOAS, Lucy S.; ARAUJO, Evaldo Stanislau A.; LEVI, Jose Eduardo; PANNUTI, Claudio Sergio; O'CONNOR, David; KALLAS, Esper GeorgesBackground: High genetic diversity at both inter-and intra-host level are hallmarks of RNA viruses due to the error-prone nature of their genome replication. Several groups have evaluated the extent of viral variability using different RNA virus deep sequencing methods. Although much of this effort has been dedicated to pathogens that cause chronic infections in humans, few studies investigated arthropod-borne, acute viral infections. Methods and Principal Findings: We deep sequenced the complete genome of ten DENV2 isolates from representative classical and severe cases sampled in a large outbreak in Brazil using two different approaches. Analysis of the consensus genomes confirmed the larger extent of the 2010 epidemic in comparison to a previous epidemic caused by the same viruses in another city two years before (genetic distance = 0.002 and 0.0008 respectively). Analysis of viral populations within the host revealed a high level of conservation. After excluding homopolymer regions of 454/Roche generated sequences, we found 10 to 44 variable sites per genome population at a frequency of >1%, resulting in very low intra-host genetic diversity. While up to 60% of all variable sites at intra-host level were non-synonymous changes, only 10% of inter-host variability resulted from non-synonymous mutations, indicative of purifying selection at the population level. Conclusions and Significance: Despite the error-prone nature of RNA-dependent RNA-polymerase, dengue viruses maintain low levels of intra-host variability.
- Low Sensitivity of NS1 Protein Tests Evidenced during a Dengue Type 2 Virus Outbreak in Santos, Brazil, in 2010(2012) FELIX, Alvina Clara; ROMANO, Camila Malta; CENTRONE, Cristiane de Campos; RODRIGUES, Celia Lima; VILLAS-BOAS, Lucy; ARAUJO, Evaldo Stanislau; MATOS, Andreia Manso de; CARVALHO, Karina Inacio; MARTELLI, Celina Maria Turchi; KALLAS, Esper Georges; PANNUTI, Claudio Sergio; LEVI, Jose EduardoIn 2010, a large outbreak of dengue occurred in Santos, Brazil. The detection of the NS1 antigen was used for diagnosis in addition to the detection of IgG, IgM, and RNA. A large number of NS1 false-negative results were obtained. A total of 379 RNA-positive samples were selected for thorough evaluation. NS1 was reactive in 37.7% of cases. Most of the cases were characterized as a secondary infection by dengue 2 virus. Sequencing of NS1 positive and negative isolates did not reveal any mutation that could justify the diagnostic failure. Use of existing NS1 tests in the Brazilian population may present a low negative predictive value, and they should be used with caution, preferentially after performing a validation with samples freshly obtained during the ongoing epidemic.