It is a historical fact: a team of scientists from the Gregorio Marañón Hospital in Madrid and the IrsiCaixa AIDS Research Institute in Barcelona (Spain) have succeeded in eliminating HIV in a group of patients. That’s right: HIV has been undetectable in blood and tissues after undergoing stem cell transplants.
In all, five HIV-infected people received a stem cell transplant. In one of them, apart from the virus being undetectable in blood and tissues, antibodies are not detected in its blood either.
In the study carried out by Spanish scientists and published in the Annals of Internal Medicine magazine, it is stated that certain factors associated with stem cell transplantation could contribute to the elimination of the viral reservoir in the body . This resolution has been thanks to stem cell transplantation that will allow, in the future, the design of HIV cure strategies that are much less invasive than the current ones, since stem cell transplantation is exclusively recommended to treat serious hematological diseases.
Timothy Brown: the beginnings
The study is based on the case of HIV patient Timothy Brown, from Berlin (Germany), who in 2008 underwent a stem cell transplant to treat leukemia. In this case, the donor had a mutation called CCR5 delta 32 that made his blood cells immune to HIV (this mutation prevents the virus from entering the blood cells). Brown eventually stopped taking antiretroviral medication and after 11 years without treatment, the HIV virus has not shown any signs of life. That is why he is considered the only person in the world cured of HIV.
Since that time, scientists have been studying plausible HIV eradication mechanisms associated with stem cell transplantation.
Thus, the IciStem consortium created a unique cohort of infected people who underwent a transplant to cure a hematological disease, in order to design new cure strategies. The participants had survived at least 2 years after receiving the transplant.
After transplantation, all participants maintained antiretroviral treatment and managed to remit the hematological disease after stopping taking immunosuppressive drugs. The experts observed that 5 of the patients had an undetectable reservoir in blood and tissues.
Why is this important?
It is important because these factors are always detected in HIV-infected people, whether or not they take antiretroviral drugs. It should be taken into account that all patients with an undetectable HIV reservoir had received an umbilical cord blood transplant.
As if this were not enough, in one of the patients, the viral antibodies had completely disappeared. “This fact could be proof that HIV is no longer in your blood, but this can only be confirmed by stopping treatment and checking whether the virus reappears or not,” explains María Salgado, co-author of the work.
This milestone in medicine could serve to design less complex and invasive HIV cure strategies. In fact, the next step will be to carry out a clinical trial, controlled by doctors and researchers, to interrupt antiretroviral medication in some of the subjects and administer new immunotherapies; This way we can check if there is a rebound of the virus or if HIV is completely eliminated from the body.
Referencia: Mechanisms that contribute to a profound reduction of the HIV-1 reservoir after allogeneic stem cell transplant. Annals of Internal Medicine, 2018. doi: 10.7326/M18-0759
