The AIDS virus is no longer detected in an American who had received a bone marrow transplant to treat his leukemia. "Cure" that experts comment with caution.
A patient "cured" of AIDS? The new challenges necessarily. For if antiretrovirals can now maintain at a very low presence of the virus in a patient, no one knows yet completely eradicate the disease. HIV is always present at low doses in patients. But this time, German scientists believe they have managed to remove all traces of HIV in a patient. An article published in the journal Blood explains how a bone marrow transplant, conducted as part of a treatment against leukemia, has resulted in this novel result.
In 2007, Timothy Brown, an American HIV positive 40 years living in Germany, is treated by Dr. Gero Hütter University Hospital the Charité Berlin for leukemia, cancer of the immune system. He is undergoing chemotherapy and radiotherapy, which suppress their immune cells completely failed. Then he underwent a bone marrow transplant, intended to produce new healthy immune cells. With the approach of the transplant, he was asked to stop taking antiretroviral drugs for fear that hinder the success of the operation.
A rare genetic mutation
But the donor was not only chosen for its compatibility with Timothy. It is also carrying a genetic mutation rare, which makes her immune cells resistant to the major forms of HIV (90% of the sexually transmitted virus). Like about 1% of the European population, it has inherited from both parents of a mutated CCR5 gene. With that, he has no CCR5 receptors on the surface of immune cells attacked by HIV LT4. It is these receptors that act as "gateway" for HIV. In their absence, the virus can no longer colonize immune cells.
The graft was successful, Timothy Brown has now rate of immune cells similar to a healthy person. And the cells now produced by his body are resistant to HIV because they carry the mutated gene. The researchers, who feared that the cessation of antiretroviral lead quickly to an outbreak of the virus, find three and a half later that the viral load is undetectable. This leads them to believe that the patient is cured of AIDS.
Hailed by the scientific community, however this result is upheld with the utmost caution. On the one hand, it is possible that the virus, although undetectable, still be present in very small quantities in cells "Sanctuaries", even if the court has reduced the number of them, according to German researchers. HIV is highly mutagenic, we can not exclude that then evolves to find another route of entry into the immune system, for example using other receptors called CXCR4.
Moreover, the method used by Dr. Hutter could not be generalized to other patients because it is too risky, experts say. The mortality rate after a bone marrow transplant is much higher than for a patient infected with HIV followed medically. It also includes a high risk of complications and may deteriorate the quality of life significantly.
This publication confirms nevertheless the interest of the runway of gene therapy for treatment of AIDS.
Lefigaro.fr
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