Scientists say this explains why some people experience a slower disease progression

Apr 29, 2014 20:13 GMT  ·  By
Researchers find why some HIV-infected people experience a slower disease progression
   Researchers find why some HIV-infected people experience a slower disease progression

Having low cholesterol levels in certain immune cells explains why it is that some people who get infected with HIV take much longer than others to become ill, researchers argue is a recent paper published in the journal mBio.

In their paper, the scientists who worked on this research project explain that, upon entering the body, HIV is picked up by specific immune system cells dubbed antigen-presenting cells, otherwise known as APCs to the scientific community.

These then carry the virus to lymph nodes and allow it to infect other immune cells such as Th cells. As shown by previous studies, Th cells constitute the chief replication site for HIV, meaning that the virus relies on them to thrive and eventually overwhelm an individual's immune system.

However, it sometimes happens that, even without being treated with antiretroviral medication, some folks who become infected with HIV experience a much slower disease progression. Specifically, the virus takes years, sometimes even over a decade, to compromise their immune system or cause AIDS.

“A fascinating aspect of the AIDS epidemic is that a small percentage of HIV-1-infected persons maintain a relatively normal number of CD4 T cells (Th cells) and low viral load for many years without receiving antiviral therapy,” explains specialist Giovanna Rappocciolo.

EurekAlert informs that these few people, i.e. about 1 in 20, whom researchers refer to as nonprogressors or controllers, owe their slower disease progression to the fact that specific immune cells in their body have low cholesterol levels.

Thus, scientists have found that, when compared to APCs belonging to ordinary folks, those of nonprogressors are characterized by low cholesterol levels and a limited ability to pass HIV to other immune cells, including Th cells.

Because of the limited ability to facilitate trans infection of their APCs, controllers can go several years without having their immune system compromised by the HIV virus.

Interestingly enough, it appears that nonprogressors' APCs have low cholesterol levels despite the fact that cholesterol levels in these people's blood are normal, specialist Giovanna Rappocciolo says. Hence, it is believed that this trait is inherited.

The scientists expect that their findings will help gain a better understanding of HIV progression, maybe even enable specialists to roll out better ways to prevent and manage infections with said virus.

As Giovanna Rappocciolo puts it, “Knowing how these individuals naturally control their HIV-1 infection and prevent the virus from progressively destroying their Th cells could be critically important to developing effective therapeutic and prevention strategies for HIV-1/AIDS.”