HIV DNA persists in spinal fluid despite treatment, linked to cognitive impairment

By Angela Betsaida B. Laguipo, BSNJul 16 2019

Many people living with the human immunodeficiency virus (HIV) and using antiretroviral therapy (ART) may still have cells sheltering the virus lurking in the cerebrospinal fluid, a new study has found.

A team of researchers at the University of Pittsburgh, Yale, and the University of Carolina wanted to investigate why people with well-controlled HIV that had undergone long-term treatment still experienced cognitive impairments.

“I don't know of a single infectious disease that is easier to treat when it's in the brain than when it's elsewhere in the body," Dr. John Mellors, M.D., senior author and chief of University of Pittsburgh Division of Infectious Diseases. "It is difficult to target infections that lurk in the brain and HIV is probably not an exception to the rule. We have our work cut out for us in the quest for an HIV cure, but knowing is half the battle, so I'm cautiously optimistic,” he added.

Antiretroviral therapy (ART) is a combination of medicines used to treat HIV infection. Everyone who is infected with HIV is recommended to take ART as soon as they know they have the virus. Even though ART does not cure HIV, the medicines can help infected people live longer and healthier lives.

The main objective of ART is to reduce the viral load of the patient to undetectable levels. When a patient reaches an undetectable viral load, it means that the level of virus in the blood is too low to become detected by the test.

Illustration of HIV Virus in blood stream. Credit: RAJ CREATIONZS / Shutterstock

HIV DNA can thrive in cells in the spinal fluid

In this new study, published in the Journal of Clinical Investigation, researchers found that people with HIV under treatment are more likely to experience memory and concentration problems than those without cells that have HIV.

With funding from the National Institute of Health’s AIDS Clinical Trials Group, the team analyzed cerebrospinal fluid from 69 patients undergoing long-term antiretroviral therapy (ART). The patients’ age range between 45 and 56 and had their infections controlled with medicine for an average of nine years.

The researchers analyzed each of the patient’s cerebrospinal fluid for HIV DNA and compared the information to their standard neurocognitive evaluation results. They found that half of the participants had viral DNA cells in the spinal fluid, hinting the presence of the latent virus. This is despite tests showing their HIV RNA viral load of HIV-cell free CSF fluid were only positive in 4 percent of the patients.

Of these, 30 percent of patients with HIV DNA in the spinal fluid had clinical neurocognitive problems than the 11 percent whose spinal fluid had no detected viral DNA.

Presence of HIV-infected cells can trigger a recurrence of active infection

“HIV-infected cells persist in CSF in almost half of the individuals on long-term ART, and their detection is associated with poorer neurocognitive performance,” the researchers concluded in the study.

Since some patient still has HIV DNA thriving in a few blood cells, once the treatment stopped, the presence of these vital genetic materials can trigger a recurrence of active infection. The researchers, however, emphasized that did not establish a causal relationship between the presence of the cells and cognitive impairment. They explained that there could be many explanations for the findings, such as it possible that the level of original infection in the central nervous system was higher in the group harboring the cells with HIV DNA.

Human Immunodeficiency Virus (HIV) by the numbers

Cases of human immunodeficiency virus (HIV) infection is increasing by the minute. In fact, the World Health Organization (WHO) reports that more than 70 million people have been infected with HIV since the beginning of the epidemic. From those individuals, 35 million have died.

Across the globe, it's estimated around 40 million people are living with the virus, with Africa still the most severely affected. There, about one in 25 adults are living with the disease, accounting for about two-thirds of all the people living with HIV worldwide.

In the United States, an estimated 1.1 million individuals are living with HIV, and about 15 percent of them are still unaware they are infected. About 38,700 people in the country became newly infection in 2016 alone.

In 2017, a total of 940,000 people have died from HIV-related diseases globally.

However, progression to Acquired Immunodeficiency Syndrome (AIDS), which is a fatal complication of HIV, can be prevented through antiretroviral therapy (ART).