Public health strategies for combating the HIV pandemic may be thwarted by “elite suppressors,” people who have AIDS but do not test positive for it in some tests, according to scientists at Johns Hopkins.
The current standard test for HIV ? the serological testing algorithm for recent HIV seroconversion (STARHS) ? distinguishes newly infected patients from those chronically infected based on the concentration of HIV antibodies in their blood, according to an announcement by Johns Hopkins Medical Institutes at the International Conference on AIDS in Toronto this week. The amount of antibodies increases with time, allowing doctors to estimate how long a patient has been infected and more effectively track the spread ofHIV.
Elite suppressors are “making STARHS and tests like it harder to use for determining incidence,” chief of the Center for Prevention and AIDS Administration Claudia Gray said.
The study does not call into question the test?s ability to determine if someone has AIDS because “if people have an HIV infection, they will have antibodies,” Gray said. “Elite suppressors have a smaller amount, but if the antibodies are there, they will test positive.”
There should be no confusion with a basic antibody test, said Mary Muzzuca, nursing supervisor for Howard County Health Department?s HIV Program. “We do as much as we can to make sure people know if they need to have the test repeated,” she said. “But whether people get tested often or not, being able to lower your chances is possible by advocating for safer sex and for partner testing.”
The Hopkins study showed as many as 280 people in Baltimore may have AIDS, but their immune systems suppress the virus to a nearly undetectable level, making them elite suppressors.
Hopkins scientists screened 1,549 people, and 183 tested positive for HIV. Testing showed 11 of those people were newly infected, but a second test called Affinity/Avidity revealed a deficiency in the STARHS test. Measuring the immune system’s response, which is weaker in a new infection than in a long-term patient, the test showed only six had new infections.
The study implies “elite suppressors” have such low blood concentrations of antibodies to HIV that they are almost indistinguishable from newly infected patients. Researchers speculated that genetics could give them stronger immune systems or that antiretroviral drugs may be a factor.
The similarity to recently infected patients may confuse scientists using the test to track the spread of HIV, the study said.
In order to accurately monitor the disease, new tests will have to discount resultsthat falsely appear new, the study?s lead researcher Oliver Laeyendecker said in a statement.
