Aspectos Imunológicos da co-infecção do Mycobacterium leprae e o vírus da imunodeficiência humana

• Ano de defesa: 2008
• Autor(a) principal: Carvalho, Karina Inacio [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Citometria de fluxo; Células NKT; Mycobacterium leprae; Imunidade inarta; Células matadoras naturais
• Link de acesso: http://repositorio.unifesp.br/handle/11600/8980

The immune response characteristics in patients infected with Mycobacterium leprae and human immunodeficiency virus (HIV) is not elucidated. The aim of this study was to evaluate different immune parameters in the overlapping of both diseases. In the first paper we observaded The co-infected group exhibited lower CD4:CD8 ratio, higher levels of CD8 T-cell activation, increased V1: V2 T cell ratio and lower percentage of plasmacytoid dendritic cells, compared to HIV-1 infected subjects. Across infected groups, IL-4 production by CD4 T lymphocytes was positively correlated with the percentage of effector memory CD4 T cells, suggesting antigenically-driven differentiation of such T cell population in both HIV-1 and M. leprae infections. Co-infection with M. leprae may exacerbate the immunopathology of HIV-1 induced disease. A T helper 2 (Th2) bias in the CD4 T-cell response was evident in both HIV-1-infection and leprosy, but no additive effect was apparent in co-infected patients. Subsequently, we evaluated quantitatively and qualitatively the NKT cells from innate immune response in HIV-infected subjects and healthy controls. The frequencies of NKT cells secreting IFN- and TNF- were significantly lower in HIV-1-infected subjects and the magnitude of the IFN- production was negatively correlated with the number of years of infection, suggesting that NKT cell function is progressively lost over time. NKT cell responses in HIV-1 infected subjects were essentially normal after treatment with Phorbol12-Myristate13- Acetato (PMA) and ionomycin, suggesting that defective TCR-signaling was the underlying defect in the cytokine production. The lower levels of the NKT Th1 response correlated with higher CD161 expression, suggesting a role for this inhibitory receptor in regulating NKT cell responsiveness. Finally, we have investigated the NKT cells in the context of HIV and M. leprae coinfection. The volunteers were enrolled into four groups: twenty-seven healthy controls, seventeen HIV seropositive patients, seventeen patients with leprosy, and twenty-three co-infected patients with leprosy and HIV-1 infection. Flow cytometric and ELISPOT assays were performed in stored PBMC. We demonstrated that coinfected patients have reduced NKT cells in the peripheral blood when compared to healthy subjects and leprosy monoinfected patients. On the other hand, NKT cells from coinfected patients secrete more IFN- when compared to leprosy monoinfected patients. These results suggest that NKT cells are highly active in coinfected patients, although occurring in lower frequency in the peripheral blood.