For the first time, a person 鈥� a baby aged 2陆 鈥� has reportedly been 鈥渃ured鈥� of HIV infection through treatment with antiretroviral drugs.
Although the claim raises the possibility of eliminating HIV infection in millions of babies, questions have been raised as to whether this particular child was genuinely infected in the first place, and whether the 鈥渃ure鈥� will be permanent.
Pregnant women with HIV usually receive antiretroviral drugs that reduce the risk of transmission to their baby from 40 to 5 per cent. If the baby does acquire HIV, he or she will be given one antiretroviral drug.
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In this case, the mother鈥檚 HIV infection was discovered too late in pregnancy for her to receive treatment to make transmission less likely. So, 30 hours after the baby was born, doctors led by Hannah Gay at the University of Mississippi Medical Center in Jackson decided to give the baby a more aggressive treatment.
Gay put the baby on three standard antiretroviral drugs. She continued the treatment for 18 months, during which time the baby was supposed to have tested positive for HIV. Then the doctors lost contact with mother and child. When they reappeared months later, doctors were astonished to find that the infant had no detectable levels of the virus, even though she was no longer taking the drugs. This is surprising since people with HIV need to take medication for life because the virus hides away in cells around the body, including in CD4 white blood cells, and re-emerges if drug treatment is discontinued.
鈥淔or 10 months she was off treatment, yet there was no trace of the virus,鈥� said Deborah Persaud of Johns Hopkins University in Baltimore, Maryland, who presented the results at a conference on in Atlanta, Georgia this week. 鈥淭he child remains off antiretroviral therapy, and this sets the stage for a paediatric cure agenda.鈥�
Time will tell
Some researchers say the claims are premature, however. 鈥淲as the child really infected, and is this 鈥榗ure鈥� going to be sustained?鈥� says John Frater of the University of Oxford. 鈥淥nly time will tell if the virus will eventually come back,鈥� he says. 鈥淭hey鈥檝e used very sophisticated tests to look for virus in the blood, but it can also hide elsewhere in the body.鈥�
鈥淚t鈥檚 been very irresponsible reporting so far,鈥� says David Margolis of the University of North Carolina in Chapel Hill. 鈥淚鈥檝e not seen the actual data yet,鈥� he says, adding that he believes the child could be a 鈥渟uper-controller鈥�, an individual with natural resistance to HIV.
Super-controllers, discovered in the early 2000s, have a genetic fault in a white-blood-cell surface receptor called CCR5. Since HIV needs to latch on to this receptor to invade cells, super-controllers are protected from infection. It turns out that about 1 per cent of Europeans have this mutation.
Only one person was previously reported to have been 鈥渃ured鈥� of HIV: a man from Germany who also had leukaemia. In 2007, he received a bone marrow transplant from a super-controller. All his blood cells thereafter carried the faulty CCR5 receptor, which effectively banished the virus from his body.
Experimental treatments
Researchers are experimenting with therapies that use 鈥済ene scissors鈥� to disable the genes that control the production of CCR5 receptors in a person鈥檚 own blood cells. One person treated this way by a company called Sangamo Biosciences in Richmond, California, showed promising results after three months but normal treatment was resumed on ethical grounds.
Another big hope is using a drug called vorinostat to flush out dormant HIV from its hiding places in the body, then kill it with antiretroviral drugs. Trials of this drug, including one led by Margolis, are ongoing.
Following the World Health Organization鈥檚 revised guidelines on preventing maternal transmission of HIV, several countries in Africa are now treating all mothers who are infected rather than just those whose CD4 cell count has fallen below 350 per millilitre of blood. A from the US Centers for Disease Control and Prevention showed that in Malawi alone, this increased almost eightfold the number of pregnant mothers receiving antiretroviral drugs, although evidence is still being gathered on whether this reduces the rate of infection in babies.
If the new triple drug regime shows potential in further studies, it could help millions of infants. In sub-Saharan Africa alone, an estimated 300,000 infants acquired HIV infection from their mother in 2011.
鈥淭his news gives us great hope that a cure for HIV in children is possible and could bring us one step closer to an AIDS-free generation,鈥� said UNAIDS executive director Michel Sidib茅.
