Foreskin of Penis Contains Cells Especially Susceptible to HIV Infection, Study States
Circumcision could help protect against HIV transmission because the foreskin of the penis contains cells that are especially susceptible to HIV infection, according to a study presented on Saturday at the annual meeting of the American Urological Association, Reuters Health reports. Circumcision is known to reduce the risk of HIV infection two- to eight-fold, although the reasons for this protective effect have been unclear (Hitt, Reuters Health, 5/28). Scientists from
Rush-Presbyterian-St. Luke's Medical Center in Chicago examined foreskin tissue from eight children and six adults. The researchers examined the tissue for the presence of CD4+ T cells, macrophages and Langerhan's cells, all of which are "major HIV target cells." When compared to samples of female cervical tissue, the foreskin tissue contained higher proportions of CD4+
T cells, macrophages and Langerhan's cells, and adult foreskin tissues contained the highest proportion of such cells. CD4+ T cells and Langerhan's cells found on the inner surface of the foreskin were seven times more susceptible to HIV infection than cervical tissue cells infected under the same condition, the researchers stated (Estrada et al., "Biologic Mechanisms of HIV Infection of Human Foreskin: Implications for Transmission," May 2002). "During sexual intercourse, this inner layer is the area that becomes traumatized and infected. In fact, we were not able to infect the outer layer of foreskin," lead study author Carlos Estrada said. He stated that in developing countries, the "circumcision of children could provide a protective effect down the road." The scientists also found that the HIV receptor CCR5 was "especially predominant" on foreskin tissue cells infected with the virus. This finding suggests that products that block CCR5 receptors and that could be applied topically to the penis or vagina should be developed, the study states (Reuters Health, 5/28).
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