December 17, 2010
A new report finds that nearly four years after a bone marrow transplant, a patient with both HIV and leukemia appears to be free of HIV. "Our results strongly suggest that cure of HIV has been achieved in this patient," wrote the investigators, led by Thomas Schneider of Berlin's Charite-University Medicine.
The patient underwent the stem cell transplant in 2007, with researchers using bone marrow from a donor who had a genetic mutation affecting the CCR5 receptor, which HIV uses to enter the cells it infects. People with the delta 32 mutation, most of whom are of Northern European descent, are naturally resistant to the virus.
The team followed the patient, testing samples from his colon, liver, spinal fluid, and brain -- all suspected reservoirs where HIV can hide out for years -- as he developed conditions that warranted the tests. The researchers found no evidence of HIV, which can evade detection unless it is actively infecting cells.
The man appears to have a fully functioning immune system that is genetically identical to the donor's cells, not his own immune cells, the team found.
AIDS experts caution that bone marrow transplants are too radical and risky to be considered feasible on any kind of scale. The procedure, a last-ditch treatment for cancers like leukemia, involves destroying a patient's own bone marrow and then transplanting cells of a donor with a nearly identical blood and immune system match. Months of recovery are needed as the patient's immune system reconstitutes.
"It's not practical and it can kill people," said HIV co-discoverer Dr. Robert Gallo of the Institute of Human Virology at the University of Maryland. "It is possibly a cure, that's for sure, you won't know for absolute sure until the person dies and undergoes extreme PCR [genetic] analysis of post-mortem tissue," he said.
Scientists are exploring gene therapy as a way to treat or cure HIV, however the technology is still in the experimental stages.
The study, "Evidence for the Cure of HIV Infection by CCR5Delta32/Delta32 Stem Cell Transplantation," was published early online in the journal Blood (2010;doi:10.1182/blood-2010-09-309591).