Web edition: July 27, 2012
Print edition: August 25, 2012; Vol.182 #4 (p. 11)
Cocaine hinders HIV fight
Cocaine use in HIV patients reduces amounts of much-needed immune cells and seems to hamper the virus-fighting activity of these and other cells and proteins, two studies show. Researchers tested 18 HIV-positive people who had similar T cell counts, 10 of whom were cocaine users. Compared with nonusers, the cocaine group had fewer newly trained T cells emigrating from the thymus, where nascent T cells get specific functions and are sent forth to fight disease. The finding suggests thymus function is impaired by cocaine, said Joumana Zeidan, an immunologist at the Vaccine & Gene Therapy Institute of Florida in Port St. Lucie. In the other study, gene analyses showed defective cell signaling that made cocaine users more prone to producing regulatory T cells, a variant form that actually dampens the immune reaction against HIV. These people also had more immune cells that were susceptible to undergoing programmed cell suicide. Zeidan presented both studies July 23. — Nathan Seppa
Heartburn drugs tied to fractures in HIV patients
Proton pump inhibitors, marketed for acid reflux under such names as Prilosec and Nexium, might increase the risk of bone breaks in HIV patients, a study in more than 40,000 middle-aged male veterans shows. Among this group, there were 588 fractures over an average of six years. People who broke a bone were nearly twice as likely to be taking a PPI as were those with no bone breaks, said Julie Womack, a nurse-researcher at Yale University who presented the data July 23. PPIs have been linked to bone weakness because the acid-blocking effect of the drugs might thwart ongoing bone remodeling processes. — Nathan Seppa
Elite controllers might thwart key viral protein
A fortunate 1 percent of people infected with HIV don’t develop symptoms of AIDS, a group termed “elite controllers” for their ability to keep the virus in check. New research finds that a key viral protein that plays several roles in HIV infection, called Nef, is largely dysfunctional in elite controllers. Viral immunologist Philip Mwimanzi of Simon Fraser University in Vancouver and his colleagues compared HIV from 45 elite controllers with 48 other patients whose disease was progressing typically. He and his colleagues found that Nef in elite controllers’ HIV was substantially less able to invade cells or replicate than Nef in the other HIV patients. In elite controllers, Nef also failed to sabotage first-alert immune proteins belonging to the HLA class, a defect that would help the immune system control the virus. — Nathan Seppa
Safer sex through soap operas
A weekly dose of educational soap operas could help keep women HIV-free, HIV prevention researcher Rachel Jones of Rutgers University in Newark, N.J., reported July 25. Jones’ team produced a 12-part video series called Love, Sex, and Choices that promoted safer sexual decisions. Women who watched the series had 19 percent fewer risky sexual encounters — unprotected sex with men they identified as promiscuous or drug users — than those who received text messages about preventing HIV, Jones and a colleague report in the July AIDS and Behavior. The soap opera followed four heroines navigating relationship dilemmas with men — like a more responsible version of Sex and the City. “The women loved the videos,” said Jones. “They watched most two or three times.” — Meghan Rosen
Cocaine: J. Zeidan et al. Cocaine use may impair recovery of thymic function and survival of recent thymic emigrants in HIV-positive adults on stable antiretroviral therapy (ART). 2010 International AIDS Conference, Washington, Abstract # MOPE018.
Cocaine: R. Bordi et al. Impact of cocaine use on the immune system in HIV-positive adults on antiretroviral therapy (ART): a systems biology approach. 2010 International AIDS Conference, Washington, Abstract # MOPE019.
Heartburn drugs: J. Womack et al. Proton pump inhibitor and protease inhibitor use are associated with fragility fracture risk in HIV-positive male veterans. 2010 International AIDS Conference, Washington, Abstract # MOPE087.
Nef protein: P. Mwimanzi et al. Functional impairment of HIV-1 Nef in elite controllers. 2010 International AIDS Conference, Washington, Abstract # MOPE006.