[JOHANNESBURG] A rare group of HIV-positive people who maintain undetectable levels of the virus in their blood without medication could hold the key to new therapies for others living with the disease, says a leading genome expert.

Unlike the vast majority of those infected, these so-called “elite controllers” can suppress the virus without the need for antiretroviral therapy (ART), sparking interest in how their immune systems function.

Researchers believe that studying these individuals, who represent about one in 200 of those infected with HIV, could lead to new treatments or even a cure.

“It appears that the elite controllers have a superior antiviral immune system that can keep the virus in check,” said Thumbi Ndung’u, director for basic and translational science at the Africa Health Research Institute and a professor at the University of KwaZulu-Natal, South Africa.

However, Ndung’u explained that the mechanisms that subdue the virus in this rare group are not uniform or fully understood.

Having an undetectable viral load means there is not enough of the virus in the body to be transmittable, so elite controllers cannot pass the virus on to others.

“Someone is generally defined as an elite controller after living with an undetectable HIV viral load for at least two years without ARVs,” Ndung’u told SciDev.Net.

For some, viral suppression will last a lifetime, but this is not always the case, he explained.

“That’s why even elite controllers have to be monitored regularly because the viral load sometimes can go up and if it goes up it is very strongly recommended that they should go on antiretroviral therapy,” added Ndung’u.

Sandra Harrigan-Thompson, a retired receptionist from Philadelphia and an elite controller, told SciDev.Net: “I know that I am different. I’ve been living for 30-something years with HIV and never had a detectable viral load.”

Harrigan-Thompson discovered her unusual status when her husband was diagnosed with HIV/AIDS in 1989. Though she expected to fall ill herself, she remained healthy and symptom-free.

Over the years, she has participated in several research studies, including donating a lymph node, in the hope of helping others with the disease.

“My blood is my gift, not only to me but to humanity or for generations to come,” she said.

In South Africa, researchers are expanding their understanding of elite controllers, particularly focusing on genetic factors that may be particular to Africans.

“One of the key questions is whether there might be genetic factors that are unique to African populations, that are specific to elite controllers compared to the rest of people living with HIV who are not elite controllers,” Ndung’u explained.

He highlighted the importance of research initiatives like the HIV Host Genome project, which aims to identify any distinct genetic traits in African elite controllers.

“We’ve found some genes involved in immune control in Africans that have been seen elsewhere, but we want to extend that work to find other genetic factors,” he explained.

The ultimate goal of this research is to replicate the mechanisms behind elite controllers’ ability to suppress the virus.

This could provide a pathway to therapies that are more effective than current treatments, especially in Sub-Saharan Africa where behavioral changes and access to ART can pose challenges.

“If we can understand these mechanisms, we might be able to use vaccines or drugs to treat or even cure HIV,” said Ndung’u.

“It’s also important even for other diseases beyond HIV because some of these antiviral mechanisms might also apply to other viruses,” he added.

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.