People with HIV have been living longer, healthier lives since the development of highly active antiretroviral therapy (or HAART) in 1995. In fact, most patients on the drug regimen do so well that, according to blood tests, their immune cells appear to return to pre-HIV levels. But two new studies from Rockefeller University and the Aaron Diamond AIDS Research Center (ADARC) show that the immune cells in other body tissues may never rebound, suggesting the need for additional ways to monitor immune system health, and the need for hypervigilance as HIV-positive patients live into their forties, fifties, sixties and beyond. The findings are reported in today's issue of PLoS Medicine and online in the Journal of Virology.
Prior research had shown that, just two to four weeks after contracting HIV-1, the lymphoid tissue layer in the mucous membrane of a patient's gastrointestinal (GI) tract can lose up to 60 percent of its CD4 memory T cells -- immune cells responsible for recognizing invaders and priming other cells for attack. Intrigued, Martin Markowitz, an Aaron Diamond Professor at Rockefeller University and a staff scientist at ADARC, wanted to know whether this loss was reversible, and whether giving patients HAART during the early infection period helped restore these cells to the GI lining the way it restored them to the blood itself.
In a paper published today in PLoS Medicine, Markowitz, Rockefeller researcher and clinical scholar Saurabh Mehandru, and their colleagues report on a trial of 40 HIV-1 positive patients who began treatment with HAART shortly after contracting the virus -- during the acute early infection phase -- and who they followed from one to seven years. The researchers found that although the blood population of CD4 T cells rebounded to normal levels, a subset of the GI tract population remained depleted in 70 percent of their subjects.