457 Determination of Viral DNA in T-cells and Monocytes/Macrophages in the Cervix and Blood of HIV+ Women M. Prakash*, S. Patterson, F. Gotch, M. Kapembwa Imperial Coll, London, UK
Background: Heterosexual transmission is the predominant route of HIV infection. To further understand the dynamics of sexual transmission and levels of virus persistence following the initiation of HAART, CD4+ bearing cells capable of harbouring virus were isolated and the level of viral DNA quantitated.
Methods:Twenty-four (24) women without evidence of cervical inflammation or sexually transmitted infection were investigated in this prospective study. Cervical intraepithelial cells were obtained using a cytobrush. Matched cervical and blood samples were obtained from HIV+ women who were therapy na´ve, receiving HAART with a low viral load (< 200 copies/mm3) and those women on HAART with a virus load > 200 copies/mm3. DNA was extracted from purified populations of T-cells and monocytes/macrophages, and the provirus load calculated using nested PCR. In addition, 4-colour flow cytometry was used to determine the relative proportion of leukocyte subpopulations. Significance was determined using a students t-test.
Results: In the cervical epithelium, macrophages constituted the predominant leukocyte subset, whereas in blood T-cells were prevalent. Viral DNA in blood resided mostly in T-cells; however, comparable levels of viral DNA was identified in T-cells and macrophages in the cervix irrespective of HAART and viral load. The level of viral DNA in cervical preparations exceeded the levels observed in blood per 10,000 purified cells. This increase was evident in women not on therapy (p < 0.05), and those on therapy with a high viral load (p < 0.05).
Conclusion: These data suggest differences exist in the immunophentypic profile of leukocytes that reside within the cervical mucosa and blood. The higher levels of viral DNA observed in the cervix indicates an important site for the transfer of virus from women to men irrespective of systemic viral load and CD4 count. Thus, despite successful HAART the cervical mucosa remains a plausible reservoir of HIV infection driving local immunodeficiency and potentially a site for the emergence of drug-resistant variants.