Experts urge caution on HIV 'miracle recovery'
Contradictory tests for antibodies may be down to a false positive.
A British man has hit headlines this week with reports that he has recovered from an HIV infection, having tested positive in August 2002 and negative in the ensuing years.
If this proves to be true on further testing, 25-year-old Andrew Stimpson, living in London, would be the first person confirmed to have eliminated HIV from his body. This would provide researchers with a fascinating test case. But experts caution that much more evidence is needed before one could say that Stimpson was cured of the killer virus.
"If it is real, it's very interesting," says Jonathan Weber, an expert on infectious diseases at Imperial College London. But he cautions that the most likely scenario based on the current evidence is "either a false positive [in 2002], or he's still infected". If the latter is true, then combing through the DNA in Stimpson's blood should reveal sequences from the virus.
A spokesperson for the Chelsea and Westminster Healthcare Trust, the part of Britain's National Health Service that performed Stimpson's tests, says it is unclear whether Stimpson will decide to undergo further analysis.
The tests that Stimpson took rely on detecting the immune system's antibodies against the HIV virus. While false positives are extremely rare, they can happen.
In 2002 Stimpson was found to be positive for these antibodies, but with an extremely low viral load. But tests done during more than two dozen visits in 2003 and 2004 proved negative for the antibodies. The trust says that it has checked and confirmed the validity of these test results, and that the samples really were from Stimpson.
Even when the virus is not multiplying rapidly in the bloodstream, it should still stimulate the production of antibodies, says Weber. Many patients living with chronic HIV infections have a very low viral load. This means that the virus is present but only in relatively tiny numbers in T cells, the immune cells that the virus eventually overruns, leading to full-blown AIDS. But these patients, despite not having any symptoms, should still test positive for antibodies.
In Kenya, a group of female sex workers has been hailed as 'resistant' to HIV. Tests for the presence of the virus and for antibodies against the virus were negative in these women, despite their repeated exposure to HIV.
Stimpson has described himself as "one of the luckiest people alive". But such celebrations are premature, HIV experts warn. "This is too early, too fast," says Simon Wain-Hobson of the Pasteur Institute in Paris. "The burden of proof is monumental."
Clinicians and virologists are also concerned that the case has been reported not in a medical journal, but as a result of the legal action Stimpson was pursuing against the trust that performed his tests.
For now, the case remains a mystery and the estimated 35 million people living with the virus are advised not to get their hopes up. "That's not to say it's not interesting," says Wain-Hobson. "But the sad news is that at best this is just one case."