| Summary: | <p>Invariant natural killer T cells (iNKTs) are capable of rapid activation and production of cytokines upon recognition of antigenic lipids presented by CD1d molecules. They have been shown to play a significant role in many viral infections and were observed to be highly activated in patients with acute dengue infection. In order to further characterize their role in dengue infection, we investigated the proportion of iNKT cells and their phenotype in adult patients with acute dengue infection. The functionality of iNKT cells in patients was investigated by both IFNγ and IL-4 ex vivo ELISpot assays following stimulation with alpha-galactosyl-ceramide (GalCer).</p> <br/> <p>We found that circulating iNKT cells proportions were significantly higher (p=0.03) in patients with acute dengue when compared to healthy individuals and were predominantly of the CD4+ subset. iNKT cells of patients with acute dengue had reduced proportions expressing CD8 and CD161 when compared to healthy individuals. The iNKT cells of patients were highly activated and iNKT activation significantly correlated with dengue virus-specific IgG antibody levels. iNKT cells expressing Bcl-6 (p=0.0003) and both Bcl-6 and ICOS (p=0.006) were significantly increased in patients when compared to healthy individuals.</p> <br/> <p>Therefore, our data suggest that in acute dengue infection there is an expansion of highly activated CD4+ iNKT cells, with reduced expression of CD161 markers.</p>
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