MORE good news from the world of AIDS. March 14th saw the publication of results from the Visconti trial (the name is a contraction of “Virological and immunological studies in controllers after treatment interruption”), being conducted in France, into the possibility of using antiretroviral drugs to produce something akin to a cure. They suggest that they can—as long as treatment starts early enough. And associated work also suggests such long-term remission may be possible for as many as 15% of those who become infected.



The Visconti trial, reported in the Public Library of Science’s journal PLoS Pathogens by Christine Rouzioux of Paris Descartes University and her colleagues, has followed the fates of 14 people treated with antiretroviral drugs shortly after they were infected with HIV, and for several years thereafter, who then (under medical supervision) had their drug treatments withdrawn. As the trial’s organisers reported to the International AIDS Conference in Washington, last July, this procedure has turned these people into what are known as “elite controllers”—that is, they still have detectable levels of HIV in their bodies years after infection, but even in the absence of drug treatment those levels do not rise significantly, and certainly not to a point where they are causing symptoms.



Elite controllers do occur naturally, but such people are unusual. Fewer than one person in 100 seems to have the potential to develop natural elite control. What causes natural elite control remains mysterious, but certain versions of what are known as HLA genes (which regulate cell-surface proteins in some immune-system cells) are rarely found in natural elite controllers.



Members of the Visconti cohort did not share this HLA signature. Moreover, their patterns of early infection were different from those of people who go on to become natural elite controllers. In such individuals the virus never really seems to take hold. In members of the Visconti cohort, it did so early and aggressively (one reason why they were treated so quickly in the first place).



Yet, after an average of three and a half years taking antiretroviral drugs, followed by an average of seven and a half years not taking them, the 14 people being followed by Dr Rouzioux and her colleagues show little or no sign of infection. Indeed, the paper suggests, even the low levels of virus still circulating in their bodies seem, in several cases, to be shrinking still further.



The crucial feature shared by people in the Visconti study is that they were put on drugs within ten weeks of infection, a point where the virus is still establishing itself in the body. This is reminiscent of what has become known as the “Mississippi baby” case, reported earlier this month, in which an infant girl, infected by being born to an HIV+ mother, was given antiretroviral treatment within a few hours of birth. Her doctors, however, lost touch with the child for five months when she was 18 months old, interrupting the treatment. When they reconnected with her they found her infection had regressed to the point of undetectability, even though she was no longer taking the drugs. This observation, combined with the Visconti trial, leads to the question of how frequent the phenomenon of elite control following early treatment actually is.



Dr Rouzioux and her colleagues attempted to estimate that from a database of French AIDS cases, and concluded that about 15% of those who are infected and treated early turn into elite controllers—though the database in question, the French Hospital Database on HIV, allowed them to draw this conclusion for only the first two years after the end of treatment.



It is all, however, extremely encouraging. If the common factor between so-called post-treatment controllers can be identified, it will allow doctors to offer treatment withdrawal to those likely to benefit from it. It will also show researchers a chink in AIDS’s armour. If they can find something which they can insert into that chink to clear the disease in other people, too, the Visconti trial may come to be seen as a turning point in the war on AIDS.