Sad news from the front of the fight against AIDS: Two HIV-positive people who underwent bone marrow transplants and were thought to be functionally cured have tested positive for the virus again.
HIV virus lives in and kills white blood cells. These blood cells are created in the bone marrow, so researchers were hopeful that they could cure the disease by wiping out the infected patient’s bone marrow and replacing it with donor marrow that wasn’t infected with the virus. This is a procedure frequently performed to treat blood cancers, so doctors are pretty comfortable with the risks, though complications can be lethal.
Two patients from Boston got bone marrow transplants to treat their blood cancer three and five years earlier. After the procedure, they were kept on drugs, and the doctors have been monitoring their blood virus levels ever since. In 2012 they announced their first results, that the patients were still free of the HIV virus years after the transplant.
To really test the “cure” though, the patients were taken off anti-HIV drugs.
Bad news struck just months after they were taken off the drugs: the virus came back. The virus was either at too low of a level to be detected while the patients were on drugs, or it could have been hiding out somewhere other than blood cells (where they normally look) in a dormant state that couldn’t be detected.
“This suggests that we need to look deeper, or we need to be looking in other tissues… the liver, gut, and brain,” study researcher Timothy Henrich, of Brigham and Women’s Hospital, told the Boston Globe.“These are all potential sources, but it’s very difficult to obtain tissue from these places so we don’t do that routinely.”
Once the drugs were removed the virus was free to exit that dormant state (or make millions of copies from the very low levels left) and re-infect the clean marrow.
Both patients are now back on anti-HIV drugs to keep the virus at bay.
While the news is horrible, it still gives us new information about what is really needed to cure the virus.
As far as we know, a bone marrow transplant has turn out to be a successful cure in only one patient, Timothy Brown, who got the bone marrow of someone lucky enough to have a genetic mutation that makes them HIV resistant. He was also given heavy doses of chemotherapy and radiation to help clean the virus out of his body before he got the transplant.
He is off drugs and has continues to test negative for the virus.
Other people, including a child who is currently 36 months old and a group of 14 patients in France, have been able to go off antiviral drugs without the virus reappearing (so far) if they get treatment early enough after first being infected. But, it’s too soon to really tell if they have been “cured” or if the virus is just hiding out in some other cells of the body waiting to reappear.
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