July 12, 2012
AUSTRALIA'S top stem-cell expert has declared a cure for HIV is finally on the way, with human trials planned for two promising techniques that aim to armour the body's immune system against the AIDS virus without the need for lifelong antiviral drugs.
Alan Trounson, who was poached in 2007 from his former position as director of the Monash Immunology and Stem Cell Laboratories to head the California Institute for Regenerative Medicine, where he contiued his research,said there was now a realistic hope the treatments would succeed in fireproofing the body's immune cells against HIV, which infects about 1000 people every year in Australia.
Professor Trounson, whose institute has helped to fund the research using some of the $US3 billion it raised for stem-cell work, will extol the promise of the approaches in a lecture at the University of NSW tonight.
Both techniques seek to remove or disable a receptor on the surface of immune cells that HIV uses to infect them. The idea is that blocking this entry point will stop HIV from reproducing but the immune cells will not be harmed.
...Although both approaches are theoretical they are inspired by a real-life patient, Timothy Brown, who remains the only person worldwide to have been cured of HIV infection after receiving a bone marrow transplant to treat leukemia.
Mr Brown's doctor chose a bone marrow donor with a gene mutation that meant he lacked the CCR5 receptor HIV needs to invade immune system cells.
Professor Trounson said the transplanted immune cells not only successfully treated the leukemia but proved immune to attack from the HIV hiding in the patient's tissues -- allowing him to stop the antiretroviral drug treatment he had been taking daily.
Researchers now hoped to induce a similar response in other HIV-infected patients by isolating blood stem cells from the patients' own bodies, artificially changing their genes in the laboratory so they share the mutated CCR5 receptor that HIV cannot use and reinfusing them back into the patients' bodies.
"It will take another six to seven years before it gets into general public use, if it all works properly," Professor Trounson said.
"If something turns up that means it doesn't work effectively enough, it will take longer."
Risks included the possibility that HIV might find another route to attack immune cells, he said.
Tony Kelleher, head of the immunology and pathogenesis program at the Kirby Institute at the University of NSW, said the technique was "definitely something worth looking at".
However, he said the new treatment would require careful scrutiny if it involved the significant risks and side-effects of bone marrow transplants, given that antiviral drugs currently allowed HIV patients to live 30 to 40 years in relatively good health.