HIV DNA declines rapidly in some infants who start ART soon after birth
Two new South African studies have shown that HIV-positive infants who start antiretroviral therapy (ART) within days of birth can rapidly reduce their viral load and viral DNA. While this is not the same as curing HIV, researchers do consider reducing viral DNA a crucial step toward finding a cure. However, the dramatic responses to treatment seen in these studies may occur only in a minority of cases.
Kirsten Veldsman of Stellenbosch University described a decline in HIV RNA and DNA in five infants treated with ART within eight days of birth. In three of the infants, significant declines in HIV RNA occurred within 3.3 months; in the other two, significant declines HIV RNA took 6.3 and 6.7 months, respectively.
In all the infants, HIV DNA was cleared much more quickly than it is in adults. Over the first 15 days of treatment, HIV DNA in the infants decreased very quickly; then it began to decline more slowly. However, even this slower rate of decay in infants treated soon after birth was faster than the rate of decay seen in patients who began treatment later. The median rate of decay was 200-fold in each month of treatment. This rapid decline in HIV DNA may be due to the faster turnover of CD4 cells in infants.
Another South African study suggests that this rapid response to treatment may be unusual. Infants who began ART within the first month of life at Rahima Moosa Mother and Child Hospital experienced a wide range of viral load responses. One-third of the 75 infants who have been studied so far achieved undetectable viral load, but this took anywhere from 90 to 330 days. In the remaining two-thirds of the infants, viral load either never fell to undetectable levels or rebounded after initial suppression. In three infants, HIV RNA fell to levels undetectable by qualitative PCR. “If they presented for HIV diagnosis, they would test negative for HIV,” explained Dr. Louise Kuhn of Columbia University.
However, it remains to be determined whether HIV DNA has now fallen to undetectable levels in those infants.
Researchers consider clearing the reservoir of HIV-infected cells a key step toward developing a cure for HIV infection.
The possibility of eliminating HIV infection in infants treated soon after birth was first reported in 2013, when researchers found that HIV infection appeared to have been cleared in the “Mississippi baby,” who started ART within days of being born. However, HIV DNA remained detectable at a very low level in the “Mississippi baby,” and the patient's infection later reemerged.
Since then, researchers have focused on finding out whether the disappearance of HIV in infants treated soon after birth is common, and whether it is possible to completely eliminate HIV DNA in those infants. It is thought that if it is possible to achieve persistently undetectable levels of HIV DNA, that might indicate that the pool of HIV-infected cells had been eliminated and that the risk that the virus would reemerge after stopping treatment would be low. The question remains whether it is possible to achieve persistently undetectable levels of HIV DNA by starting treatment soon after birth.