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| Author(s): |
Raquel Müller Gonçalves
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2010-04-05 |
| Examining board members: |
Marcelo Urbano Ferreira;
Gil Benard;
Silvia Beatriz Boscardin
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| Advisor: | Marcelo Urbano Ferreira |
| Abstract | |
This study compares levels of circulating cytokines and peripheral-blood populations of CD4+CD25+ Treg cells, based on the expression of FOXP3 and CTLA-4, and dendritic cells (DCs) in individuals infected with P. falciparum, P. vivax or co-infected with both species and in healthy controls living in an area of unstable transmission of malaria in the Brazilian Amazon. Blood samples from 76 malaria patients and 18 malaria-exposed but non-infected controls were collected and processed to obtain mononuclear cells. Cell populations were characterized by flow cytometry and levels of circulating cytokines were measured by capture ELISA. Acute infection induced an increase in the proportion of CD4+CD25+FOXP3+CTLA-4+ cells (p= 0.0029, Kruskal-Wallis) and a decrease in the absolute number of DCs (p= 0.0008, Kruskal-Wallis), being both effects independent of the infecting parasite species. 35-40% of the P. vivax-infected subjects (but none in the other groups of subjects) had few circulating DCs expressing the co-stimulatory molecule CD86, a putative marker of DC activation. The only variable associated with a low proportion of CD86+ DCs was the proportion of CD4+CD25+FOXP3+ expressing CTLA-4. Analysis of circulating cytokine levels revealed increased levels of IFN- <font face=\"Symbol\">γ in P. falciparum infection (p= 0.0050, Kruskal-Wallis); although IL-10 levels were high in all infected individuals, compared with exposed controls (p<0.0001, Kruskal-Wallis), the increase was much more pronounced in vivax malaria. Plasmodium falciparum and P. vivax</i. appear to stimulate different patterns of immune response in humans, even when comparisons are limited to individuals with uncomplicated malaria exposed to similar levels of malaria transmission. (AU) | |