Temple researchers may have discovered the monocyte subset leading to the advancement of HIV to AIDS.
Monocytes, white cells in the bloodstream, help the immune system to fight against infections. Once monocytes leave circulation, they go into tissues, where they begin to differentiate into macrophases. Macrophases perform various jobs, including cleaning up debris in case of injury and containing immune stimulatory properties.
Just like monocytes, not all macrophases are the same, varying based on the environment they are in, and some of the factors that are secreted by infectious cells.
Within the HIV study, Temple researchers found a monocyte subset with two surface markers – CD+16, a cluster of differentiation that provides antibodies, and CD+163, an iron cluster containing molecules working towards protection from injury.
According to the March issue of AIDS Research and Human Retroviruses, this monoctye subset may be in direct correlation with the progression of HIV to AIDS.
“We looked at a single time point in patients, and we saw that this correlation exists,” said Dr. Jay Rappaport, one of the three researchers who oversaw the study.
Rappaport said when the HIV viral load increases, so does the subset of monoctyes.
“The higher the viral load, the higher the fraction of this subset becomes,” he said. “It becomes more predominant.”
As the monocyte subset begins to increase, a person begins to lose their CD+4 T-cells. CD+4 T-cells are crucial in helping to maintain the immune system.
“The lower the CD+4 count, the higher the fraction of these cells becomes,” Rappaport said.
The study, authored by Dr. Tracy Fischer-Smith of Temple, first began with a group of monkeys containing the Simian Immunodeficiency Virus, the primate version of AIDS. From there, 25 patients from Temple’s Comprehensive HIV program – 18 of them with the virus and seven without – were chosen at random by Dr. Ellen Tedaldi.
“In order to see if this predicts the rate of production to disease, the next step would be to do a longitudinal study and to follow those patients overtime,” Rapport said. “We think that it could be something that could allow you to forecast the progression of the disease. Right now, there’s very little out there that can do that.”
With the use of microarray technology, the longitudinal study will examine the gene expression profile cells, and how they function in the context of the immune system. This information could prove that the more monocytes a person has, the more prone they are to the HIV progression to AIDS.
Temple’s Office of the Provost has awarded Dr. Ellen Tedaldi with a seed grant to further explore the study of patients with HIV. The research study will include a five-faculty member staff led by Dr. Trisha Acri, covering up to one-year of research.
Kylee Messner can be reached at firstname.lastname@example.org.
Image courtesy of Nature.com