David Cohen, contributor
Does one man's apparent recovery from HIV herald the dawn of a cure for the disease?
The internet is abuzz with press reports claiming that a new cure for HIV is on the horizon. This flurry began last week with a paper in the journal Blood, followed by an interview with the patient himself in the German magazine Stern, and has since spread around the web like wildfire, including reports in CNN and Associated Press.
The research itself isn't new - the paper in Blood is a follow-up analysis of a treatment performed in 2007 and first published in 2008.
The trial involved Timothy Ray Brown, an AIDS sufferer who had developed myeloid leukemia (a cancer of the immune system). Brown's doctors, Gero Hütter and his colleagues at the Charité University of Medicine, Berlin, treated him with heavy doses of chemotherapy to suppress the cancer. They then followed this with a bone marrow transplant containing stem cells from a matched donor - a routine treatment for this sort of cancer.
However, crucially, the stem cells had an extra potency. Hütter knew that about 1 per cent of Europeans have a natural resistance to HIV conferred by a mutation in a gene called CCR5, so he searched for a donor from within this population.
The transplant was a success and the donor's immunity seems to have been passed to Brown via the transplant. All this was known in 2008.
In their latest paper in Blood, the researchers confirmed that Brown seems to have maintained his resistance to HIV for three years, confounding their expectation that he would become reinfected. They concluded that a "cure of HIV has been achieved in this patient."
Note the crucial words "in this patient". For the transplant to succeed, the bone marrow had to be specifically matched to Brown so that his immune system would not reject them. He was lucky that a match was found. Furtherore, as Michael Saag, director of the University of Alabama at Birmingham AIDS Center, told CNN, Brown had to have his own immune system practically wiped out to avoid a rejection of the transplant, a risky procedure in itself.
Though some press reports have suggested this could herald a treatment for AIDS, in reality this is unlikely to be the case. As New Scientist pointed out in a thorough analysis of the trial at the time, while being fantastic news for Brown, for all the above reasons and more, it is still a far cry from a treatment that can scale to the millions of AIDS sufferers worldwide.