September 29, 2000

MGH study shows immune system can control HIV

An MGH research team has shown that the majority of HIV-infected individuals who begin antiviral therapy during the earliest stages of their infection eventually can stop taking drugs and keep the virus under control with their immune systems alone. In the study reported in the Sept. 28 issue of Nature, a group of eight such patients took part in closely supervised interruptions of their drug treatment. While the course for each participant has varied, all participants achieved at least temporary suppression of the virus for several months.

Currently five of the eight participants are still off drug treatment after 8 to 11 months, maintaining viral levels below the level at which treatment would be recommended. Of the three who resumed taking medication, two participants chose to restart and only one was required to reinstate treatment because of rising viral levels.

"This is the first time that anyone has shown that the immune system can successfully be manipulated to keep HIV under control,"says Bruce Walker, MD, director of the Partners AIDS Research Center at the MGH, the paper’s senior author. "We want to deliver two messages with this report: that diagnosing HIV infection and beginning antiviral treatment as early as possible can make a fundamental difference in the way the immune system handles the virus, and that HIV treatment strategies based on the immune system – including vaccines – appear to have great potential. We also want to stress that persons currently taking the anti-HIV drug cocktail referred to as HAART [highly active antiretroviral therapy] should continue taking their drugs."

The findings are an extension of previous research showing that early treatment with HAART can allow HIV-infected individuals to retain a population of HIV-specific T helper cells, the "generals"of the immune system that coordinate defense against viruses and other pathogens. The current result supports the theory that those T helper cells can mount an effective response against HIV in patients, duplicating the natural HIV suppression seen in so-called long-term non-progressors.

The researchers note that, at this time, only those who began antiviral treatment during acute infection and show signs of anti-HIV immune system activity have been able to go on to control virus without drugs. Studies in persons who first start HAART six months or more after infection – the majority of infected persons – are yet to be done. Eric Rosenberg, MD, the paper’s lead author, says: "While we’re confident that someday we will be able to apply these finding to treatment of chronic HIV infection, there’s a lot more we need to learn about augmenting the immune system’s response against HIV. We also owe a huge vote of thanks to these patients who are pioneers in what could have been a risky venture."

The study’s co-authors are Marcus Altfeld, MD, Samuel Poon, Mary Phillips, RN, Barbara Wilkes, Robert Eldridge, Gregory Robbins, MD, Richard D’Aquila, MD, and Philip Goulder, MD, PhD, all of the Partners AIDS Research Center and the MGH Infectious Disease Division.