February 12, 2009

Man Shows No Signs Of HIV After Stem Cell Transplant

Researchers say an HIV positive man in his early 40s no longer shows any sign of the virus two years after undergoing a stem cell transplant from a donor with a rare resistance to the disease.

A report published Wednesday in the New England Journal of Medicine said the stem cell donor was among the 1 percent of Caucasians who have the variant gene mutation that blocks a receptor known as CCR5, which is normally found on the surface of T cells, the type of immune system cells attacked by HIV.

Dr. Gero Hutter, a hematologist at Benjamin Franklin Hospital in Berlin, performed the transplant along with a team of medical professionals on an American man living in Germany that had been diagnosed with HIV 10 years ago.

The patient had been on antiviral drugs since his diagnosis and even developed leukemia in 2006.

"Our thinking was that if we do this and replace his immune system with cells that are resistant to HIV, we can do two things at once by stopping his leukemia and his HIV infection," Hutter said in an interview with Bloomberg News.

Hutter said two years after the procedure the patient is still without any detectable signs of HIV and has been taken off of antiretroviral medications.

Dr. Jay Levy, a professor at the University of California San Francisco, who wrote an editorial accompanying the study, said while promising, the treatment is unlikely to help the vast majority of people infected with HIV.

"A stem cell transplant is too extreme and too dangerous to be used as a routine treatment," he said.

Stem cell transplants are risky procedures that deliberately damage a patient's immune system in an effort to establish a new, healthy immune system from donor stem cells.

"About a third of the people die during such transplants, so it's just too much of a risk," Levy told CNN news.

However, Levy, who wasn't involved in the study, said the results are likely to stimulate a lot of companies to put more emphasis on gene therapy.

Before the procedure, Hutter's team scanned the genomes of 60 potential donors and found one who lacked the CCR5 section. They even stopped the patient's antiviral therapy one day after they transfused the donor's stem cells into the patient.

"There's been no rebound of HIV," Hutter said.

Levy said less invasive options to alter CCR5 could come within the next five years or so.

"It's definitely the wave of the future," he said.


Image Caption: Scanning electron micrograph of HIV-1 budding from cultured lymphocyte. This image has been colored to highlight important features. CDC


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