HIV researchers have long known that, in rare cases, patients can suppress the virus naturally without medication. The phenomenon has fascinated scientists for decades but has remained unexplained.

New research could aid in the search for treatments for HIV-infected patients. (Source: Drugs.com)

A recent study published in the journal Science Immunology has identified at least one reason for this phenomenon.

Only about one in 300 people can control HIV without medication, said study author Dr. Bruce Walke, professor of medicine at Harvard Medical School and director of the Ragon Institute of MGH, MIT and Harvard.

New research has identified an unusually potent version of white blood cells, called CD8+ T cells. In humans, CD8+ T cells are a type of T cell (lymphocyte-like immune cell). In the immune system, CD8+ T cells play an important role in responding to pathogens such as virus-infected cells and cancer cells. In HIV-infected patients, CD8+ T cells often accumulate in the lymph nodes.

Researchers have discovered that people infected with HIV have the ability to automatically destroy HIV and prevent it from causing disease, these CD8+ T cells are much more "adept" at identifying and blocking HIV.

Dr. Bruce Walker said it appears that the CD8+ T cell response is responsible for this control. To understand this better, the team analyzed blood samples and T cells from seven healthy people who were not infected with HIV, 19 HIV-infected patients who were controlling their virus naturally, and 17 typical HIV patients whose viral loads were controlled by antiretroviral therapy (ART).

Today, ART therapy has dramatically changed the course of HIV, suppressing the virus and giving patients the chance to live a near-normal life. However, the therapy also causes certain side effects and is expensive.

In HIV-infected patients who are in control of the virus, CD8+ T cells are “very abundant and highly functional,” Walker said. In contrast, in HIV-infected patients on antiretroviral therapy (ART), CD8+ T cells are fewer in number and less functional.

The bottom line, he added, is that in patients who are controlling the virus themselves, these “enhanced” CD8+ T cells “are blocking HIV from doing harm.”

Dr. Walker and his team say they are trying to figure out how T cells in HIV-infected people can generate a special type of immunity against HIV.

It's a difficult goal, says Dr. Michael Horberg, director of the Center for HIV/AIDS and STD Prevention at the Kaiser Institute for Managed Care in Rockville. In nearly 35 years of clinical care for HIV patients, Dr. Horberg says he's seen very few patients with this ability.

However, according to some experts, this is an important area of ​​research that can help find treatments for HIV-infected patients and expand the scope of treatment applications for current and future diseases and pandemics.