PHILADELPHIA, Nov 08, 2001 (United Press International via COMTEX) -- Researchers at Jefferson Medical College have developed a strategy -- using a natural compound -- to flush the Human Immunodeficiency Virus (HIV) out of dormancy in the cellular reservoirs of the body.

The agent, prostratin, comes from a Samoan rainforest tree, and appears to stimulate the virus, which causes AIDS, in a way that allows the body's immune system to detect and attack it.

"What this compound does is two things: It stops HIV from infecting other cells by decreasing receptors and it drives HIV out of latency," said lead author Dr. Roger Pomerantz, chief of the division of infectious diseases at Jefferson Medical College of Thomas Jefferson University in Philadelphia.

Though the therapy was only tested in a laboratory setting, the researchers predict they will gain approval to test their hypothesis in patients as early as next year.

Prostratin could be a crucial second tier treatment in the battle against HIV, the virus that causes AIDS. In the last five years, anti-HIV drugs, known as highly active antiretrovirus therapy (HAART), have brought the virus under control by drastically reducing its presence, or load, in patients.

But HAART does not completely eradicate HIV. Instead, the virus goes into hiding and persists in undetectable levels in the blood. "Many people can get to undetectable virus levels in their blood but the virus lies fallow like a Trojan horse," said Pomerantz. "As soon as they stop drug therapy, the virus will ignite like a brush fire."

Prostratin therapy could provide a means by which to flag the furtive HIV in its hiding place. Then, by driving out the HIV, the HAART drugs and the body's own defenses can seek out and destroy it.

"This may be the first drug that might stimulate both T-cells and macrophages, both of which might be reservoirs for virus," said Dr. Pomerantz.

However, skeptics question whether Pomerantz' two-pronged approach will actually benefit HIV-positive patients.

"It's a hypothesis that's interesting but how it would work clinically is anyone's guess," said Dr. Robert Buckheit, director of infectious disease research at the Southern Research Institute in Birmingham, Ala.

"It's an approach that, in the clinical community, there would be some level of resistance to. This is something that would turn the virus on and clinical prognosis is related to the levels of virus in the system," he said.

In fact, determining how much of the virus needs to be "turned on" in order for the immune system and the HAART drugs to kill it, will be the most challenging part of developing prostratin for clinical use.

"You want to stimulate miniscule amounts of the disease and that will have to be figured out empirically. You'd have to model it in vitro and through animal studies," said Dr. Pomerantz.

It's too soon to say that prostratin, for all its promising performance, will eradicate HIV-disease, said Dr. Suraiya Rasheed, professor of pathology at the University of Southern California School of Medicine in Los Angeles.

"When protease inhibitors were given to patients, researchers claimed that HIV will be 'eradicated'. This was 12 years ago," she said.

Prostratin was discovered in Samoa by an American ethnobotanist. The results of the NIH-funded study will be published in the Nov. 15 issue of the journal Blood.

　　From healthy.net