In 2007, an HIV-positive man from the U.S. faced a leukemia diagnosis while living in Berlin. He underwent a bone marrow transplant to try to cure his leukemia. However, this was also an opportunity for him and his doctors to better control, or even cure, his HIV. A bone marrow donor was found who had HIV-resistant stem cells. Due to a genetic mutation called delta-32, these cells did not produce the R5 co-receptor found on immune cells, which HIV uses to get in and reproduce.
In late 2010, an article appeared in the journal, Blood, and reported on this patient's progress now nearly 4 years after the operation. Initially, some thought HIV would reappear given that the virus is present in resting cells which eventually become reactivated and start producing HIV again. However, he continues to have normal CD4s and undetectable viral load while having been off HIV treatment for nearly 3.5 years now.
About a year after his first transplant, his leukemia returned and so another transplant was done with the same type of stem cells. His leukemia is now in remission. And although tests previously found some HIV that uses another co-receptor, called X4, his HIV has not converted to using that co-receptor and has indeed not been found in recent testing of his blood. Researchers have also found that CD4s have come back in various parts of his body including gut lymph tissue ... a very strong sign of immune reconstitution.
For more information on this fascinating development in HIV research, go to AIDS Meds.