Photo by Susie Fitzhugh
Why are some people who are infected with HIV naturally able to control replication of the virus? An international research consortium involving Dr. Julie McElrath and other clinical researchers from the Seattle HIV Vaccine Trials Unit—a joint program of the Hutchinson Center and the University of Washington—is a significant step closer to understanding the genetics of "elite controllers." These are the rare HIV-positive people who can control the virus without treatment, keeping the levels of HIV in their blood extremely low sometimes for as long as 25 years after infection.
The research consortium, led by researchers in Boston, published its findings Nov. 4 in an early online edition of Science. The study involved 1,500 elite controllers around the world—including 16 from the Seattle HVTU—as well as more than 300 investigators at some 200 institutions. Those from Seattle included co-authors McElrath and Julie Czsartoski, a nurse practitioner and research clinician in the Seattle HVTU.
The researchers found that variants in a protein that alerts the immune system to the presence of infection may underlie the rare ability of some individuals to control HIV infection without the need for medications. They also found that differences in five amino acids in a protein called HLA-B are associated with whether or not HIV-infected individuals can control viral levels with their immune system only.
“This study is important because it showed how a specific genetic makeup can lead to HIV control,” McElrath said. “Ultimately, the findings may help provide insight to HIV-1 vaccine designs that may be effective for those who are HIV seronegative.”
Call for HIV-negative study volunteers
The Seattle HVTU is recruiting volunteers for two studies that look at immune responses to HIV vaccines.
- One study is looking at HIV-negative pairs of twins to see if their immune responses to a study vaccine differ between identical and fraternal twins. The Twins Study will help researchers understand how much of the immune response is controlled by genetics versus the environment.
- The other study is enrolling HIV-negative participants and is looking at the immune responses to a vaccine. The Hope Takes Action study needs HIV-negative gay men 18-50 years old.