Some women found able to naturally block HIV infection

Three studies examining uninfected wives of HIV-positive men in England and Thailand found that some women seem to be able to naturally ward off HIV infection, Newsday reports. The studies, all carried out independently, indicated that an “as-yet-unidentified protein” is protecting these women, who have engaged in unprotected sex with their HIV-positive husbands for several years. Researchers found elevated levels of CD8 white blood cells in the “HIV-resistant” women in all three studies. One study also found a “soluble suppresive factor” in test subjects’ blood, mostly likely produced by macrophages, that was shown to inhibit viral growth in a laboratory setting. The same two-pronged immune system defense of elevated CD8 cells and macrophage suppresive factor has already been identified in nonconverting prostitutes in Kenya and Thailand. Researchers hope to isolate the protective protein, analyze it, and determine whether it might offer clues for effective HIV treatment or vaccination.