Made available in DSpace on 2014-12-17T14:13:42Z (GMT). No. of bitstreams: 1 HenioGL_TESE.pdf: 1861952 bytes, checksum: 59df83a02a682e8397eb8b241531d77b (MD5) Previous issue date: 2011-11-16 / Visceral leishmaniasis (VL) is a disease caused by protozoa of the Leishmania donovani complex, whose infection has clinical spectrum ranging from asymptomatic infection to active disease characterized by fever, cachexia, hepatosplenomegaly, and immunosuppression. The healing or protective immunity require an antigen-specific type 1. The Montenegro skin test (DTH) has been interpreted as a marker of protective immunity. However, there is no known correlation between the DTH response to type 1 and DTH and immunity of type 1 are maintained in the long term. Thus, a longitudinal study of 8 years, nested in a cohort family held in Brazil, documented the status of DTH and cytokine production by peripheral blood mononuclear cells in response to antigen-specific stimulation. This study was the interdisciplinary approach of physicians, biochemists, nutritionists, veterinary medicine, biology and statistics. The results show that 46.2% of subjects were analyzed DTH positive at baseline. The prevalence of positive and DTH induration size increased with age (p = 0.0021). 15.7% of individuals positive DTH "retro-converted" the negative and 50.4% (64) of individuals negative DTH became positive. The size of DTH induration was correlated significantly with the antigen-induced production of IFN-γ (r = 0.6186, p = 0.0001). IL-6 was secreted at higher levels in peripheral blood mononuclear cells of individuals who "retro-converted" DTH positive to negative than individuals who remained stable DTH status (p = 0.005). Thus, IFN-γ produced by peripheral blood mononuclear cells, may be a surrogate marker for protective immunity instead of the DTH response. In addition, differences in innate immune response may determine whether individuals maintain or eliminate the infection by Leishmania infantum chagasi in asymptomatic patients / A leishmaniose visceral (LV) ? uma doen?a ocasionada por protozo?rios do complexo Leishmania donovani, cuja infec??o possui espectro cl?nico variando desde infec??o assintom?tica a doen?a ativa caracterizada por febre, caquexia, hepatoesplenomegalia e imunossupress?o. A cura ou prote??o exigem uma imunidade ant?geno espec?fica do tipo 1. O teste cut?neo de Montenegro (DTH) tem sido interpretado como um marcador de imunidade protetora. No entanto, n?o se sabe a correla??o do DTH com a resposta tipo 1 e se o DTH e a imunidade do tipo 1 s?o mantidos a longo prazo. Assim, um estudo longitudinal de 8 anos, aninhado a uma coorte familiar realizada no Brasil, documentou o status do DTH e a produ??o de citocinas por c?lulas mononucleares do sangue perif?rico em resposta a estimulo ant?geno-espec?fico. Os resultados obtidos mostram que 46,2% dos indiv?duos analisados foram DTH positivos no in?cio do estudo. A preval?ncia do DTH positivo e o tamanho da endura??o aumentaram com a idade (p = 0,0021). 15,7% dos indiv?duos DTH positivos retroconverteram a negativos e 50,4% (64) dos indiv?duos DTH negativos tornaram-se positivos. O tamanho da endura??o do DTH correlacionou-se significativamente com a produ??o ant?geno induzida de IFN-γ (r=0,6186, p=0,0001). IL-6 foi secretado em n?veis mais elevados por c?lulas mononucleares do sangue perif?rico dos indiv?duos que retroconverteram de DTH positivo para negativo do que os indiv?duos que mantiveram o status de DTH est?vel (p=0,005). Assim, o IFN-γ, produzido por c?lulas mononucleares do sangue perif?rico, pode ser um marcador substituto para a imunidade protetora em vez da resposta DTH. Al?m disso, as diferen?as na resposta imune inata podem determinar se os indiv?duos mant?m ou eliminam a infec??o por L. infantum chagasi em assintom?ticos