The London citizen infected with HIV entered a long remission after a stem cell transplantation, which also helped him to beat the cancer. This is the second case in the world when a patient defeated HIV after a stem cell transplant.
Doctors believe that this procedure cannot be considered as a way to treat millions of people infected with HIV and at risk of developing AIDS. However, it can help develop an effective treatment that will change the patient’s DNA with high accuracy.
The curing of the “London patient”, whose identity has not been disclosed, occurred after several unsuccessful attempts to reproduce the results of 2008, when Timothy Brown, the Berlin patient, became resistant to HIV infection in the process of treatment of leukemia with stem cells. This gave rise to new hopes that the disease, which is now being restrained in patients with the daily intake of expensive drugs, can soon be cured with a single injection of constructed immune cells.
Using the data, obtained from these two patients, scientists with the help of genetic engineering and immunotherapy will be able to develop a treatment for the disease, which claimed 35 million lives and still kills 940 thousand people per year.
“This is both really exciting and really important”, – said Jonah Sacha, an immunologist at Oregon Health and Science University who studies HIV and was not involved in the new research. “It really gives a lot of hope to the HIV-cure field. But it also underscores the scale of the task ahead. It’s huge.”
Worldwide, nearly 37 million people are infected with the human immunodeficiency virus. About 21 million people take antiretroviral drugs every day to suppress the infection.
However, drug resistant strains appear regularly. This raises medical concerns about the long-term effectiveness of modern antiretroviral drugs and added the need to find a way to kill HIV “with one shot” once and for all.
The London patient has been taking anti-retroviral drugs for a long time to suppress HIV, which he was diagnosed with in 2003. In 2012, he was also diagnosed with Hodgkin’s lymphoma.
The patient underwent a course of chemotherapy, which did not bring any improvement. In addition, doctors could not obtain the necessary stem cells from him for autologous transplantation. Then they turned to the international registry in search of a suitable stem cell donor. In addition to histological compatibility, doctors were looking for a certain kind of gene that the donor should inherit from both parents.
Scientists believe that this gene, known as CCR5, plays a key role in the penetration of HIV into cells. Those who have two copies of a version of a gene known as CCR5 Delta32 appear to be resistant to HIV.
It took considerable effort, but the researchers were able to find a donor who fit the bill. Following standard blood cancer treatment protocols, doctors killed and suppressed much of the patient’s immune system, and then transplanted a population of stem cells obtained from the donor’s bone marrow.
16 months after transplantation, the patient’s immune system contained a new pair of CCR5 genes.
Despite the fact that the patient was fully aware of what could happen if he refused antiretroviral therapy, he stopped taking the drugs. The tests performed showed that even 18 months after the refusal of drugs, HIV RNA was not detected in his blood. According to a report, published in Nature, the London patient’s body appears to have completely suppressed the virus.
Although only time will tell whether his remission is permanent, the London patient has no signs of both Hodgkin’s lymphoma and HIV infection.
The study authors made clear that they don’t expect stem cell transplants to become the standard treatment for HIV. Transplants, which are currently used mainly for the treatment of blood cancers, are expensive, complex and extremely dangerous.
The Berlin and London patients provided scientists with important information about the genetic mechanism that may act as a switch on HIV control. If you use the knowledge gained in immunotherapy and other treatment methods that are already widely used, it could pave the way to healing.
The effective elimination of HIV in both men confirms the investigators’ long-held assumption that having two copies of CCR5 Delta32 essentially knocks the gene out and prevents the most common form of HIV from entering human cells for replication.
“It’s quite clear that the CCR5 receptor is absolutely a critical part of what HIV needs to enter cells”, – said Dr. Otto Yang, an infectious disease specialist and HIV researcher at UCLA.” Turning that knowledge into an HIV cure will take many, many more steps”.