New AIDS Therapy Nukes HIV
Radioactive Antibodies Seek and Destroy HIV Infected Cells in Mouse Study
Current therapy for HIV -- known as highly active antiretroviral therapy or HAART -- uses a combination of powerful drugs that keep the AIDS virus from replicating. When treatment is successful, the virus seems to disappear from the blood.
But once treatment stops, the virus eventually comes back. That's because HIV hides in a few long-lived cells -- so-called latent HIV infection.
If a person gets HAART treatment very, very soon after infection, it's possible to stop the virus before it can establish hideouts. But there is a very narrow window of opportunity to begin this treatment -- as little as a day, and certainly within 72 hours of exposure.
That's because HAART has to work before it starts to replicate within cells. But if radioimmunotherapy were available, the treatment could seek out infected cells and kill them -- effectively widening the window of opportunity to eliminate HIV infection.
Moreover, new strategies are being developed to flush HIV out of hiding. Such strategies, combined with radioimmunotherapy and HAART, might conceivably eradicate HIV, even in established infection. But that hope lies far in the future.
Dykes notes that the researchers haven't yet shown that radioimmunotherapy can track down HIV anywhere in the body. She notes that in the current study, the treatment hit HIV only in liver, spleen, and thymus cells.
"It will be interesting to see whether you could get the radioimmunotherapy to target all the different areas that HIV gets to in the body," she says. "I have a feeling this treatment probably wouldn't cross the blood/brain barrier and get to HIV in the brain."
Dykes agrees with Goldstein that a major benefit of radioimmunotherapy would be to help people for whom HAART simply doesn't work very well.
"A lot of patients out there don't have a lot of treatment options left," Dykes says. "For those patients, this treatment -- which, after all, involves radiation -- might be something they would be willing to do."
"While two-thirds of people with HIV respond well to HAART, others don't," Goldstein says. "If we treat them with radioimmunotherapy to reduce the number of infected cells, we may be able to take patients who are not responsive and make them responsive to HAART."
Dadachova, Goldstein, and colleagues report their findings in the November issue of the open-access, online journal PLOS Medicine.