Scientists from the Institute for AIDS Research IrsiCaixa in Barcelona and the Gregorio Marañón Hospital in Madrid have managed to get six HIV-infected patients to have the virus removed from their blood and tissues after undergoing stem cell transplants.
The research, published today in the journal Annals of Internal Medicine, has confirmed that the six patients who received a stem cell transplant have the virus undetectable in blood and tissues and even one of them does not even have antibodies, which indicates that HIV could have been eliminated from your body.
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 the complete replacement of the recipient cells by those of the donor – eighteen months in one of cases- could have contributed to a potential disappearance of HIV, which opens the door to designing new treatments to cure AIDS.
IrsiCaixa researcher Maria Salgado, coprimera author of the article, together with Mi Kwon, hematologist of Hospital Gregorio Marañón, explained that the reason that drugs do not cure HIV infection is currently the viral reservoir, formed by cells infected by HIV. the virus that remain dormant and can not be detected or destroyed by the immune system.
This study has pointed out certain factors associated with stem cell transplantation that could help to eliminate this reservoir from the body.
Until now, stem cell transplantation is recommended exclusively to treat serious hematologic diseases.
The study has been based on the case of 'The Patient of Berlin': Timothy Brown, a person with HIV who in 2008 underwent a stem cell transplant to treat leukemia.
The donor had a mutation called CCR5 Delta 32 that made their blood cells immune to HIV, since it prevents the virus from entering them.
Brown stopped taking antiretroviral medication and today, 11 years later, the virus still does not appear in his blood, which is considered the only person in the world cured of HIV.
Since then, scientists are investigating possible mechanisms of HIV eradication associated with stem cell transplantation.
To do this, 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.