NEW METHOD TO TARGET HIV

A new technique, traditionally used to treat cancer, could potentially also be used to eradicate HIV-infected cells from the body.

Researchers at Albert Einstein College of Medicine of Yeshiva University in New York have found that radioimmunotherapy (RIT) could be used to target cells infected with the virus.

Current highly active antiretroviral therapy (HAART) keeps HIV from multiplying by killing the virus in the bloodstream. It does not cure patients infected with HIV, however, because it does not completely eliminate the HIV-infected cells in which the virus can replicate.

The new findings presented on Tuesday at the annual meeting of the Radiological Society of North America (RSNA) could solve this problem.

“There have been major strides in HIV treatment that slow disease progression, but we’re still searching for a permanent cure,” said study leader Ekaterina Dadachova, Ph.D., professor of radiology and of microbiology & immunology.

“To combat HIV, we need a method that will completely eliminate all HIV-infected cells without damaging non-infected cells.”

In RIT, historically known as a cancer treatment, radioactive isotopes attached to antibodies selectively target and destroy cells. After the antibodies deliver the radioisotope to a specific target, such as a cancer cell or disease-causing microbe, the radioisotope delivers a lethal dose of radiation without harming healthy cells.

Dr. Dadachova in collaboration with her colleagues Arturo Casadevall, M.D., Ph.D. and Barry Zingman, M.D., administered RIT to blood samples from 15 HIV patients treated with HAART.

They found that RIT was able to specifically kill HAART-treated lymphocytes and reduce HIV infection to undetectable levels in the majority of samples.

The Einstein researchers also investigated whether the RIT approach can reach HIV-infected cells in the brain and central nervous system. Current anti-retroviral therapy drugs do not efficiently penetrate the blood-brain barrier, a system of blood vessels that stops harmful substances from crossing into the brain.

This is why many HIV patients treated with HAART often suffer from severe cognitive impairment. Using a laboratory model of the blood-brain barrier constructed of human cells and developed by Joan Berman, Ph.D., they showed that the same radiolabeled antibodies used in earlier experiments could eliminate HIV-infected cells in the brain without damaging the barrier.

“We found that radioimmunotherapy could kill HIV-infected cells both in blood samples that received antiretroviral treatment and within the central nervous system, demonstrating RIT offers real potential for being developed into an HIV cure,” said Dr. Dadachova.