Beyond the Mississippi Baby

Researchers learn lessons from case of infant thought to have been cured of HIV

News in early 2013 that an infant in Mississippi might have been cured of HIV after receiving early and potent antiretroviral treatment at birth inspired hope that other babies whose infection had not been prevented could also be cured. This was especially exciting because, although in wealthy countries the widespread use of perinatal antiretroviral therapy has almost completely prevented new cases of HIV in newborns, worldwide 700 babies are born each day infected with HIV.

Encouraged by the Mississippi and several similar cases around the world, a nine-country clinical trial was developed by the NIH to see if more expeditious diagnosis and treatment of HIV infection at birth might lead to eventual clearance of the virus as the young immune system matures.

When in July 2014 it was announced that the then famous “Mississippi baby,” after 27 months off treatment with no detectable HIV, had experienced a rebound of virus, researchers were determined to try to understand how a remission that lasted more than two years had been achieved. Although disappointing, the case has generated a lot of new information. It has also led to a number of hypotheses regarding how early viral reservoirs are established, the cell types in which the virus hides, how the virus secures its long-term persistence, and very importantly, the challenges  in detecting very low levels of latent virus.

Infants are born with immature immune systems that respond to HIV infection differently than the immune systems of newly infected adults. An infant immune system has not yet learned how to respond to infections the way an adult’s has, and indeed it does not even possess all of the immune cells of an adult immune system.

Recognizing the opportunities to learn more about potential differences in curing infants versus adults, amfAR convened a think tank in March 2015. It brought together twelve scientists expert in HIV and/or pediatric immunology, to discuss what is known and, more importantly, not known about the neonatal immune system, its response to HIV infection, and the challenges of testing interventions in infants.

Several researchers not yet active in HIV found the discussions so intriguing they committed themselves to moving into the HIV field and to bringing their unique new insights into solving elements of the puzzle. The group also began designing new research studies for amfAR to consider funding. These ideas will be fleshed out more fully at a follow-up think tank in the coming months.