CD8+ T lymphocyte expansion, proliferation and activation in dengue fever.

Dengue 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 São 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.

Short communication: Molecular characterization of HIV type 1 BF pol recombinants from São Paulo, Brazil.

In the Brazilian HIV-1 epidemic, subtypes B, C, and F1 are cocirculating in the population. Sequences of the partial pol gene from 463 HIV-1-infected patients were obtained from plasma samples and viral subtype was characterized. BF recombinants were found in 8% of the samples. Fifteen different patterns were observed. A CRF28_BF and CRF29_BF structure was found in 29.7% of the samples, CRF12_BF in 13.5%, and CRF39_BF in 2.7%. Two other patterns were identified in each of three samples. These findings could indicate a new CRF description, but to determine this a full length study is required.