Stem cells have been credited with all sorts of medical magic. Now it looks as if they may have cured a man of his HIV infection.
In 2007, the 40-something-year-old American underwent a blood stem cell transplant to treat leukemia. His donor not only was a good blood match but also had a mutant gene that confers natural resistance to HIV, the virus that causes AIDS.
Now, three years later, the man shows no sign of leukemia or HIV, according to a report in the journal "Blood."
"It's an interesting proof-of-concept that with pretty extraordinary measures a patient could be cured of HIV," but it is far too risky to become standard therapy even if matched donors could be found, said Dr. Michael Saag of the University of Alabama at Birmingham.
He is past chairman of the HIV Medicine Association, an organization of doctors who specialize in treating AIDS.
Transplants of bone marrow - or, more commonly these days, of blood stem cells - are done to treat cancer, and their risks in healthy people are unknown. It involves destroying the person's immune system with drugs and radiation, and then replacing it with donor cells to grow a new immune system. Mortality from the procedure or its complications can be 5 percent or more, Saag said.
"We can't really apply this particular approach to healthy individuals because the risk is just too high," especially when drugs can keep HIV in check in most cases, Saag said. Unless someone with HIV also had cancer, a transplant would not likely be considered, he said.
When the man's case surfaced two years ago, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the procedure was too expensive and risky to be practical as a cure but that it might give more clues to using gene therapy or other methods to achieve the same result.