No HIV After Stem-Cell Transplants: Researchers
Two more patients undergo 'sterilizing cure,' advancing understanding of the process
The so-called "Berlin patient," Timothy Brown, is the first documented case of a sterilizing cure for HIV. An American man living in Germany who received a bone marrow transplant for leukemia, Brown has remained HIV-free even after discontinuing his antiretroviral drug therapy. The transplanted bone marrow cells came from a donor who had a rare genetic mutation that increases immunity against the most common form of HIV, and researchers believe that helped protect Brown from re-infection.
In Mississippi, a baby born with HIV nearly three years ago is the first case of a "functional cure," in which early treatment eradicates the virus. Immediate treatment with antiretroviral medications rid the child of all traces of HIV within the first month of life, and she has remained virus-free even after discontinuing drug therapy at 18 months of age.
Henrich's findings are significant because his two patients did not receive bone marrow cells with the genetic mutation that helped Brown. They also did not receive the intensive chemotherapy or total body irradiation that preceded Brown's stem-cell transplant.
Instead, their stem-cell transplants appear to have been protected by the patients' ongoing antiretroviral therapy, which continued as they received cancer treatment.
"In bone marrow transplants, the donor cells actually eliminate and replace the host patient's blood cells," Henrich said. "Antiretroviral therapy allowed the donor cells to replace the host cells without becoming infected."
By comparing Brown with the two new patients, researchers hope to better understand the immune responses that have protected all three, said Rowena Johnston, vice president and director of research for amfAR, the Foundation for AIDS Research, which is funding Henrich's research.
"It was quite unclear at the time how that cure came about," Johnston said of the Brown case. "One way these Henrich findings are significant is that they allowed us to tease apart those factors that may have been key to curing Timothy Brown."
Together, the three patients can tell researchers a lot about the barriers to a cure and how they might be overcome, Johnston continued.
Perhaps some day the treatment that helped these patients will be available to everyone with HIV, she added.