P15-19. Highly HIV-exposed HIV uninfected Kenyan female sex workers display a thick ectocervical epithelium

*Maria Röhl [1], *Julie Lajoie [2,3], Annelie Tjernlund [1], Gabriella Edfeldt [1], Carolina Wählby [4], Genevieve Boily-Larouche [3], Julianna Cheruiyot [5], Makubo Kimani [5], Joshua Kimani [2,3], Julius Oyugi [2,5], Keith R. Fowke [2,3], Kristina Broliden [1]
Affiliates: [1] Unit of Infectious Diseases, Karolinska Institutet [2] Department of Medical Microbiology, University of Nairobi. [3] Department of Medical Microbiology, University of Manitoba. [4]Centre for Image Analysis, Uppsala University. [5] Kenyan AIDS Control Program, University of Nairobi *Equal contribution

Background
The female genital tract is a critical site of HIV acquisition and a number of genetic and immunological correlates of relative resistance against infection have been described in the ectocervical mucosa. We hypothesize that a thick epithelium, a high concentration of epithelial junction proteins, together with a low concentration of HIV target cells (CCR5+CD4+T cells and dendritic cells) at a distant location is a beneficial combination that hinders sexual acquisition of HIV.

Methods
Ectocervical biopsies were collected from female sex workers from Nairobi, Kenya, representing highly HIV-exposed but HIV seronegative who had been involved in sex work for 7 years or more (HESN) (n=29), HIV-infected (n=11), and uninfected individuals who were new to sex work (3 years or less) (n=39). Digital image analysis of immunofluorescent staining was used to identify genital mucosal factors affecting HIV susceptibility by characterizing the thickness and integrity as well as the spatial distribution of HIV target cells in the cervical epithelium.

Results
Preliminary results indicate that the HESN group display significantly thicker epithelium than the HIV+ group, and significantly lower numbers of potential HIV target cells than both the HIV+ group and those who were new to sex work.

Conclusion
A deeper insight into what mucosal factors are affecting HIV susceptibility is of major importance to prevent sexual HIV transmission, and we hope to contribute to this needed knowledge.