In the early years of the AIDS epidemic, being infected with the virus that causes the disease was considered a virtual death sentence. But with the development of antiretroviral therapy, many with HIV are now living much longer. In fact, it is estimated that by 2015, about half of all HIV-positive individuals will be older than 50.
The researchers specifically focused on "naive" T-cells – those that had not previously encountered any pathogens and thus act as a reserve against future infections and cancers. They found that in individuals infected with HIV-1, these cells underwent unexpectedly rapid aging – the equivalent of 20 to 30 years of aging within three years of infection. They also found that the number of CD31- T-cells, which are more quickly pulled into the fight against new pathogens, had fallen drastically.
The researchers also investigated whether appropriate treatment could reverse this aging effect. They examined cells from HIV-positive individuals who had been on antiretroviral therapy for two years and whose therapy had successfully kept HIV-1 under control. They found that while the therapy kept their viral loads at undetectable levels, it did not entirely restore their immune systems, suggesting a reason why younger HIV-positive people still become ill with conditions more common to older people.
"Taken together, our results help to explain some of the clinical observations that have been documented in HIV-infected people and emphasize the need for developing therapeutic approaches directed at improving the naive immune cell compartment," said senior investigator Beth D. Jamieson, an associate professor of medicine in the division of hematology and oncology at the David Geffen School of Medicine at UCLA. "This is critically important in light of the demographic shift of HIV-infected persons."
Source: University of California – Los Angeles