People infected with HIV whose immune cells have low cholesterol levels experience much slower disease progression, even without medication, according to University of Pittsburgh Graduate School of Public Health research that could lead to new strategies to control infection.
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. The discovery, funded by the National Institutes of Health (NIH), is featured in today’s issue of mBio, the journal of the American Society for Microbiology.
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.
“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.”
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).
“We couldn’t have made this discovery without the MACS. Results like ours are the real pay-off of the past three decades of meticulous data and specimen collection,” said senior author Charles Rinaldo, Ph.D., chairman of Pitt Public Health’s Department of Infectious Diseases and Microbiology, and professor of pathology. “It is thanks to our dedicated volunteer participants that we are making such important advances in understanding HIV, and applying it to preventing and treating AIDS.”