A new study suggests targeting HIV with radioimmunotherapy could eradicate HIV from infected cells. If given in conjunction with highly active antiretroviral therapy, it may form the basis of a cure.
Although highly active antiretroviral therapy (HAART) kills human immunodeficiency virus (HIV) in the bloodstream, it does not completely eliminate it from the body because the virus can linger in infected cells and replicate.
Researchers from the Albert Einstein College of Medicine of Yeshiva University in New York presented their findings at the 99th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA) in Chicago, IL, this week.
Study leader Ekaterina Dadachova, professor of radiology and of microbiology & immunology, says although there has been enormous progress in HIV treatments that slow progression to AIDS, the search for a permanent cure continues. She explains:
"To combat HIV, we need a method that will completely eliminate all HIV-infected cells without damaging non-infected cells."
In radioimmunotherapy (RIT), which has been used for a while to treat cancer, antibodies charged with radioactive isotopes target and destroy cancer cells.
The antibody selects the particular type of cancer cell and the attached radioisotope delivers a lethal dose of radiation that kills the target cell, while leaving untargeted (healthy) cells unharmed.
HIV infection reduced to undetectable levels
In previous work, Prof. Dadachova had already managed to use the approach in the lab to target and destroy human immune cells infected with HIV.
At the meeting, she and her colleagues presented the results of a study in which they used the approach to treat blood samples from people infected with HIV.
The blood samples came from 15 HIV patients receiving HAART treatment at the AIDS Center at Montefiore, the University Hospital for Einstein College and academic medical center.
The results showed that RIT targeted and killed HAART-treated lymphocytes - types of white blood cells - and in most samples, reduced HIV infection to undetectable levels.
The team then went on to see if RIT could reach HIV-infected cells in the brain and central nervous system.
This would be a big step because current antiretrovirals do not cross the blood-brain barrier very well, which is why so many HIV patients treated with HAART often have severe mental impairment.
For this test, they used a lab model of the blood-brain barrier made with human cells and discovered that the same radioisotope-charged antibodies used in earlier experiments could destroy HIV-infected cells in the brain without damaging the barrier.
Prof. Dadachova says:
"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."
In another study published recently in the Journal of Infectious Diseases, researchers from Lund University in Sweden describe how they found that an aggressive new HIV strain leads to AIDS more quickly than other current strains.