Some HIV-infected people experience much slower disease progression even without medication than other people who are infected. Scientists at the University of Pittsburgh have identified that it happens because they have low cholesterol levels in specific immune cells.
"We've known for two decades that some people don't have the dramatic loss in their T cells and progression to AIDS that you'd expect without drug therapy," said lead author Giovanna Rappocciolo, Ph.D., an assistant professor at Pitt Public Health. "Instead the disease is much slower to progress, and we believe low cholesterol in dendritic cells may be a reason."
“A fascinating aspect of the AIDS epidemic is that a small percentage of HIV-1-infected persons, termed nonprogressors or controllers, maintain a relatively normal number of CD4 T cells (Th cells) and low viral load for many years without receiving antiviral therapy,” said Rappocciolo.
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,” she added.
The Pitt Public Health researchers found that low cholesterol in certain cells, which is likely an inherited trait, affects the ability of the body to transmit the virus to other cells.
When HIV enters the body, it is typically picked up by immune system cells called dendritic cells, which recognize foreign agents and transport the virus to lymph nodes where it is passed to other immune system cells, including T cells. HIV then uses T cells as its main site of replication. It is through this mechanism that levels of HIV increase and overwhelm the immune system, leading to AIDS.
Once a person develops AIDS, the body can no longer fight infections and cancers. Prior to effective drug therapy, the person died within one to two years after the AIDS diagnosis.
The discovery was made possible by using 30 years of data and biologic specimens collected through the Pitt Men's Study, a confidential research study of the natural history of HIV/AIDS, part of the national NIH-funded Multicenter AIDS Cohort Study (MACS).
The discovery, funded by the National Institutes of Health (NIH), was featured in April 29th issue of mBio, the journal of the American Society for Microbiology.
Source: Science Codex
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