LEADING AIDS researchers have dismissed as impractical a stem cell treatment for leukaemia that removed all traces of HIV from an American man living in Berlin.
German newspapers last week hurried to proclaim the man was "cured" 10 years after becoming HIV positive thanks to leukaemia treatment.
In the course of a bone marrow transplant at Berlin's Charité hospital, doctors of the 42-year-old man replaced his stem cells with those of a patient naturally resistant to the virus.
The aggressive gene therapy wipes out a patient's immune system with radiation and medication, with a mortality rate of up to 30 per cent. Some 600 days on, there is still no trace of HIV in his system.
German researchers behind the case say they hope to have made a contribution to Aids research, but caution that it will be of limited use for the 33 million people living with the syndrome. "The procedure comes with such a high mortality rate that it would be ethically unjustifiable except for this specific situation when a patient was forced to have a transplant because of another disease," said Dr Gero Hütter, one of the two Charité doctors behind the procedure.
Until now, the most effective weapon against the virus that causes Aids has been anti-retroviral drugs which can have serious side effects and may not be effective long term.
Leading Aids researchers said the Berlin procedure was unlikely to establish itself in the developed world, let alone in disease black spots like sub-Saharan Africa. "Frankly I'd rather take the medicine," said leading Aids researcher Dr Robert Gallo, in an interview with the New York Times.
The German researchers took a roundabout approach, scouring the country for bone marrow donors for patients with the required natural immunity to HIV.
The immunity, first identified a decade ago, is caused by natural genetic mutation preventing production of CCR5, the substance the HI-virus targets to enter cells.
After performing the transplant with the stem cell material of one of just 80 suitable donors in Germany, doctors instructed the patient not to take his HIV medication until the virus returned to noticeable levels.
"As of today, more than 20 months after the successful transplant, no HIV can be detected," said Dr Hütter. "We performed all tests, not only with blood but also with other reservoirs. But we cannot exclude the possibility that it's still there. The virus is tricky and it can always return."