Monday, July 30, 2012
USA - Bone marrow transplants: A cure for HIV?
The cure for HIV may be at hand as two HIV-infected men who underwent bone marrow transplant appeared to be cured of the virus.
During the 29th AIDS conference, Dr Daniel Kuritzkes, Chief of Infectious Diseases at Brigham and Women’s Hospital in Boston presented his study on two patients who have been infected for many years. The men were also unlucky to have cancer but more than two years after receiving bone marrow transplants, HIV cannot be detected anywhere in their bodies.
Kuritzkes assume that overtime the transplanted donor cells have replaced the patients’ own lymphocytes. Lymphocytes are a type of white blood cell and are a key part of the immune system.
As this occurred, the amount of HIV DNA detectable in the patients’ blood cells decreased and became undetectable. One patient has now been monitored for nearly two years since his transplant and the other for three-and-a-half years. So far, no traces of virus could be found in the patients’ plasma.
Kurtizke explains that the case was different from the “Berlin” patient, who received cells that were intrinsically resistant to HIV infection because they lacked a key HIV receptor (the CCR5 receptor), the cells the two patients received were CCR5+. He believes that continuous administration of effective antiretroviral therapy protected the donor cells from becoming HIV infected as they eliminated and replaced the patients’ immune cells, effectively clearing the virus from the patients’ blood lymphocytes.
“Everyone knows about this ‘Berlin patient’. We wanted to see if a simpler treatment would do the same thing,” he said.
But the only way to verify that the transplant plus antiretroviral therapy can eradicate HIV is to take the patients off their medication regimens.
That would be the “next logical step,” said Kuritzkes, adding that this would require patient consent and adherence to ethics protocols.
But even if the transplant procedure were found to eliminate the reservoir of latent HIV cells, bone marrow transplantation is a very risky procedure. Kuritzkes said he does not “foresee bone marrow transplantation being performed on otherwise healthy HIV-infected patients who are doing well on [antiretroviral therapy].”
Kuritzkes and his colleagues are continuing to enroll and follow HIV-positive patients who have undergone bone marrow transplants as part of a larger study.