Étude des facteurs influençant la susceptibilité à l'infection au VIH chez des femmes africaines
Initial exposure to HIV during heterosexual transmission occurs in the female genital tract. However, little is known about the local immunity, the factors influencing the susceptibility to HIV infection and the immune response in the female genital tract against HIV infection.  The aim of this study is to analyse some factors that could be implicated in the susceptibility to HIV infection and to analyse, in part, the immunity present in the female genital tract. We investigated the role of HLA-G and HLA-E in the susceptibility to HIV infection in a cohort of Zimbabwean women. We found that the presence of HLA-G*0105N allele in combination with the genotype HLA-EG/HLA-EG was associated with a decrease in the risk of HIV infection. We also measured the expression of soluble HLA-G in a study of commercial sex workers (CSW) in Benin. Levels of soluble HLA-G were lower in the HIV-1-infected CSWs compared to those observed in both the HIV-1-uninfected CSWs and the HIV-1-uninfected women from the general population at low risk of infection. We also analysed the chemokine and cytokine expression patterns in the serum and female genital tract of the three groups of women. HIV-1-infected CSWs had significantly higher blood and genital levels of the chemokines IP-10, MCP-3 and MIG compared with those in both the HIV-1-uninfected CSW and non-CSW groups. HIV-1-infected CSWs had significantly higher genital mucosal levels of the cytokines TNF-α and IFN-γ compared with those in both the HIV-uninfected CSW and non-CSW groups. In contrast, the serum levels of the cytokines IL-2, IL-10 and TNF-α were lower in HIV-1-infected CSWs compared with those in the other groups. This suggests the presence of a constant immune cells recruitment and immune activation in the female genital tract in order to favour perpetuation and dissemination of the virus. Our results also demonstrate the important difference between the systemic and the mucosal immunity. We also observed a significant increase in the levels of IL-4, MIP-1α, MIP-1β and MCP-1 in the serum of the HIV-1-uninfected CSWs. It seems that these highly-exposed and yet uninfected women can have a better capacity to mount an early immune response against HIV. This study gives us new insights of the mucosal immunology of HIV infection.
HIV HLA-G HLA-G Immunologie Mucosal immunology Africa Cytokines Cytokines Chemokines