Low cholesterol slows HIV progression - study

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Why some HIV-infected experience slower disease progression, even without medication? It has to do with cholesterol levels in specific immune cells, scientists have found, Business Standard reports.

A new discovery at the University of Pittsburgh Graduate School of Public Health suggested patients with HIV could live longer if cholesterol metabolism in their immune cells is regulated, said Giovanna Rappocciolo, lead author of the study.

"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," said Giovanna Rappocciolo from University of Pittsburgh.

When HIV enters the body, it is typically picked up by immune system cells, called antigen-presenting cells (APCs), including dendritic cells and B lymphocytes.

The researchers took a closer look and discovered that the APCs from nonprogressors had low levels of cholesterol, even though the patients had regular levels of cholesterol in their blood.
Those cells then transport the virus to lymph nodes where the APCs pass it to other immune system cells, including Th cells, via a process known as trans infection.


Though Rappocciolo's study pointed out those HIV-infected individuals may stay healthy for 7 years or longer without having conventional therapies if cholesterol levels are low. But it does not guarantee that HIV patients with low cholesterol diets are protected against the virus.

"I don't want people to start thinking that if they have low blood cholesterol that they're protected from infection," Rappocciolo stressed.
At this point, it is not clear if doctors can manipulate cholesterol levels in immune cells to deliver positive benefits for patients. But Pittsburgh researchers are now investigating possible genetic methods to reduce cellular cholesterol levels in some patients.
"We think it's important because it's a very new approach to the study of the HIV infection. I think it could be significant," Rappocciolo said as quoted by TribLive.
"Understanding how this works could be an important clue in developing new approaches to prevent progression of HIV infection," Rappocciolo said. 

The findings were published in the journal mBio.