Eric Blue, a 12-year-old with HIV and leukemia who underwent a historic cell transplant at the University of Minnesota Amplatz Children's Hospital to potentially remedy both diseases, has passed away due to complications with the procedure. A similar technique has been lauded for curing three men with the virus and blood cancers, but this new development highlights the pre-existing dangers of the experimental method.

The treatment first gained mainstream attention in 2007, when Timothy Brown, an HIV-positive American expat living in Germany, received a unique bone marrow transplant to treat his leukemia. About 1 percent of Europeans carry a mutation that makes them resistant to HIV, and his doctors devised an ingenious plan of tracking down a bone marrow donor with the trait. Five years after his transplant, Brown has shown no sign of HIV or cancer, and his 'miraculous' case has been followed by two more.

In 2009 The New York Times labeled Brown's story as the "New Hope of a Cure for H.I.V.", but was this description overzealous?

Eric Blue's cancer was deemed terminal, and a transplant was absolutely required. So in April, his doctors attempted to recreate Timothy Brown's success by using cord blood cells from an HIV-resistant donor. The procedure essentially attempts to replace a patient's entire immune system with the donor's cells. This is accomplished via the use of chemotherapy, which wipes away the current immune system and can leave a patient vulnerable to infection and other complications. Brown suffered long-term neurological consequences that left him with temporary blindness and memory problems.

The outlook was initially promising for Blue, who grew up in Alexandria, La, as he had made it through the initial vulnerable stages of his treatment. Early tests had shown that he was HIV-negative and leukemia-free, even after his medications had been discontinued.

However he eventually fell victim to another common side-effect of bone marrow transplants: graft-versus-host disease. As the name suggests, this unpredictable condition happens when the donor's cells begin to attack the recipient. It is estimated to occur in 60-80 percent of transplants where the donor and recipient are not related.

Many doctors, including those with success stories, have tried to draw attention to the dangers associated with bone marrow transplants, citing that the possible lethality — 15 to 20 percent patient mortality — and the expensive price tag do not justify its broad use with HIV.

While scientific lessons can be learned from Eric Blue's tragedy and Timothy Brown's triumph, renown HIV expert Dr. Jay Levy probably stated it best when he wrote in 2009 that this strategy is "not an HIV cure, but encouraging new direction" for combating the disease.