The study at Brigham Women’s Hospital with the two or three men who had the bone marrow transplant, does it seem amazing that they didn’t have any trace of HIV at all in their blood after the transplant correct?
Dr. Mayer: These studies with bone marrow transplants are very exciting. The first one was a patient in Berlin who had leukemia and had to have a bone marrow transplant for protection. They were able to take a donor who was a match who lacked one of the receptors that HIV combined. HIV gets inside the cells through two different receptors and one of the receptors that it uses to enter cells do not appear to be necessary for human survival. In other words, people can have genetic mutations and not have the receptor at all. The team was very smart they though if we kill most of the cells in this person’s body that can contain HIV and if we treat the person with cells that can’t pick up HIV, it’s not going to be able to get inside the cell so it’s going to exhaust itself and get removed. These new patients are a very similar kind of story. The trouble is that bone marrow transplantation itself has up to ten percent mortality, because during the period of time when a person has a transplant their immune system is essentially wiped out. They can pick up these nasty infections that could kill them. If they get through that and the transplant is a success they’re home free. Bone marrow transplantation is very expensive, tens of thousands of dollars per person. We don’t think that this is a model for how you could end the AIDS epidemic. We don’t think that we’re going to start wiping out people’s bone marrows in Africa or in Asia where there’s lots of nasty infections like tuberculosis. We’d be putting people at risk for that during that period of time. Now people are doing things that are shorter and that are reversible, like chemical bone marrow transplants that could give less or a much shorter period of time. Are there other tricks of the trade we can learn from this experience of the bone marrow transplant that we can use actually cure AIDS? While it is exciting, it’s not as far along even as the vaccine. There certainly is more movement now in the past few years to find a cure than there have been in a long time. HIV hides out in these little reservoirs and the reservoirs are in the liver, the spleen, and the gut. Any tissues that contain lymphocytes and mononeural cells can contain HIV. The thought is that we have such strong antiviral medication that can suppress HIV to a very small number, but it still can hide out in some of these cells and the immune system doesn’t recognize them.
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