Immune System May Hold Key to Curing HIV

Kick and kill strategy uses vaccine to stimulate immune system.

Kick and kill strategy uses vaccine to stimulate immune system.

A treatment strategy dubbed “kick and kill” may lead to a potential cure for HIV following the results of a promising recent clinical study.

The study, published in Clinical Infectious Diseases, evaluated a treatment that stimulates the immune system with a vaccine to reawaken dormant HIV hiding in white blood cells so the boosted immune system can locate and kill the virus.

"Our study shows that the immune system can be as powerful as the most potent combination drug cocktails," study co-author Ravi Gupta, MD, said in a press release. "We're still a long way from being able to cure HIV patients, as we still need to develop and test effective vaccines, but this study takes us one step closer by showing us what type of immune responses an effective vaccine should induce."

The study evaluated a single 59-year-old male whose immune system was found to control HIV for a long period of time without requiring treatment. These patients, called elite controllers, comprise just 0.3% of the HIV patient population.

Elite controllers do, however, eventually need treatment to prevent HIV from progressing to AIDS, but their immune systems are more active against the virus to allow them to go longer without receiving treatment.

The patient in the study had HIV and multiple myeloma, which produces white blood cells that can help control HIV. As part of the myeloma treatment, the patient had his bone marrow completely removed and replaced with his own stem cells. Following removal of the bone marrow, the patient’s immune system was severely impaired, which allowed HIV to reactivate and replicate.

The patient’s viral load subsequently increased from fewer than 50 copies per ml to approximately 28,000 copies per ml before his immune function returned nearly 2 weeks after the transplant, at which point the viral load in his bloodstream rapidly dropped.

The patient’s immune system decreased the HIV levels to 50 copies per ml within 6 weeks, a rate that is similar to the most powerful drugs available.

"By measuring the strength of the immune system required to keep this virus under control in this rare individual, we have a better idea of the requirements for successful future treatment," co-author Deenan Pillay said in a press release. "We also managed to identify the specific immune cells that fought the infection. This is a single patient study, but nevertheless it is often the unusual patients who help us to understand the HIV disease process."

The patient did not receive anti-HIV medication during the study as a result of concerns regarding potential adverse events that could affect treatment for his myeloma. The study suggests an equally strong immune response in combination with powerful drugs may have been able to cure the patient’s HIV completely, but that remains uncertain, the study authors wrote.

"We need to be cautious in interpreting observations from a single subject," researcher Nilu Goonetilleke, MD, said in a press release. "However, demonstration even from a single subject, that our immune system can rapidly control HIV-1 tells us a lot about the types of immune responses we should target and augment through vaccination."