A research published this Monday in the Annals of Internal Medicine, has confirmed that, after a study carried out by researchers from the Sida IrsiCaixa in Barcelona and the Gregorio Marañón Hospital in Madrid, it has been achieved that six patients infected with HIV have eliminated the virus of HIV from your blood and tissues after being subjected to a series of stem cell transplants. 5 of the patients treated with this method have managed to have an undetectable viral load and even the sixth, has managed to eliminate the antibodies from their organism.
The patients maintain the antiretroviral treatment, but the researchers believe that the origin of the stem cells (umbilical cord and bone marrow), as well as the time elapsed to achieve complete replacement of the recipient cells by those of the donor, (up to eighteen months in one of them) could have helped the disappearance of HIV, which opens the door and new hopes to design new treatments to cure AIDS. Maria Salgado, one of the researchers from Barcelona, together with Mi Kwon, a hematologist at the Hospital Gregorio Marañón, explain that the reason drugs currently do not cure HIV infection is the viral reservoir, made up of cells infected by the virus that remain in a latent state and can not be detected or destroyed by the immune system itself.
Based on the famous case of ‘The Patient of Berlin’: Timothy Brown a person with HIV who in 2008 underwent a stem cell transplant to treat his leukemia. The donor happened to have a mutation called CCR5 Delta 32, which made their blood cells completely immune to HIV, since they prevent the virus from entering them. Brown stopped taking antiretroviral medication 11 years ago and even today, the virus remains undetected in his body, which is considered the only person in the world cured of HIV. Thanks to Timothy Brown, scientists are investigating possible mechanisms of HIV eradication associated with stem cell transplantation.
The IciStem consortium created a unique cohort in the world of people infected with HIV who underwent a transplant to cure a blood disease, with the ultimate goal of designing new strategies for cure. “Our hypothesis was that, in addition to the CCR5 Delta 32 mutation, other mechanisms associated with transplantation influenced the eradication of HIV in Timothy Brown,” said Salgado. The study included six participants who had survived at least two years after receiving the transplant, and all donors lacked the CCR5 Delta 32 mutation in their cells. “We selected these cases because we wanted to focus on the other possible causes that could help eliminate the virus,” Mi Kwon detailed. After the transplant, all the participants maintained the antiretroviral treatment and achieved the remission of their hematological disease after the withdrawal of the immunosuppressive drugs. After various analyzes, the researchers saw that 5 of them had an undetectable reservoir in blood and tissues and that in the sixth the viral antibodies had completely disappeared 7 years after the transplant. According to Salgado, “this fact could be proof that HIV is no longer in his blood, but this can only be confirmed by stopping the treatment and checking whether the virus reappears or not.” The only participant with a detectable HIV reservoir received an umbilical cord blood transplant – the rest was from bone marrow – and it took 18 months to replace all of their cells with the donor cells. The next step will be to conduct a clinical trial, controlled by doctors and researchers, to stop antiretroviral medication in some of these patients and to provide new immunotherapies to check for viral rebound and confirm if the virus has been eradicated from the body.