Release date: 2014-10-13
Can AIDS be cured? In July 2014, the famous functionally cured Mississippi baby reproduced the HIV virus, and the second recently cured “AIDS†AIDS baby also showed signs of HIV infection.
So far, only one patient infected with HIV has been successfully cured. He is the "Berlin case" Timothy Ray Brown. But no one knows for sure which treatment for Brown has cured his disease.
Now, a new experiment with monkeys provides more evidence for a hypothesis that a rare genetic mutation in a person who donates bone marrow to Brown may play a central role in his treatment. The study was published in the PLOS Pahogents on September 25.
In 2007, Brown was eliminated in Germany after receiving treatment for leukemia. In the treatment of leukemia, Brown first received radiation therapy to kill cancer cells and stem cells that produce cancer cells in the bone marrow, and then received transplants from bone marrow from healthy donors to produce new blood cells.
After treatment, Brown not only recovered from leukemia, but his HIV virus level also dropped to an undetectable level, and this situation continued, even though he had not taken the HIV virus that is usually used to maintain HIV infection. Low levels of antiretroviral (ART) drugs.
Scientists believe that there are three possibilities:
The reason why the virus has not been detected in Brown may be that donors transplanted with bone marrow have a rare genetic mutation that makes human CD4-T cells (a type of immune cell that is primarily attacked by HIV) resistant. HIV virus. This mutation, called the delta 32 mutation, produces immune cells that alter the CCR5 receptor and prevents HIV from entering the cell;
At the beginning of the treatment, the rays kill almost all of Brown's HIV-containing cells (from which the donor's genetic mutations have little effect);
Due to "graft versus host disease," new immune cells produced by transplanted bone marrow cells attack Brown's original cells. This may have killed all of the surviving cells that harbored HIV after Brown received radiation therapy.
So which one is it?
Dr. Guido Silvestri, a pathologist at Emory University in Atlanta, and his colleagues conducted a small study that gave three monkeys the same “treatment†as Brown to find out. Which step may have eliminated the HIV virus in cancer treatment.
In the study, they infected monkeys with the monkey's human immunodeficiency virus (Simian-Human Immunodeficiency Virus or SHIV), which is similar to the HIV virus and can cause AIDS-like diseases in animals. First, monkeys receive antiretroviral drugs for a period of time to mimic the situation of people infected with HIV. The monkeys then receive radiation and receive transplants from their own bone marrow stem cells obtained before infection.
The researchers found that radiation therapy killed most of the monkey's blood and immune cells, including up to 99% of CD4-T cells. This finding makes it possible to "kill all cells that store HIV by radiation may be a key step in curing Brown."
The scientists also found that within a few weeks after transplantation, the blood cells and immune cells of the HIV-free virus were produced in the monkeys, indicating that the bone marrow transplantation experiment was successful. If monkeys are found to be cured of HIV infection, researchers will be able to rule out the possibility of a “graft-versus-host disease†hypothesis because each monkey receives a transplant of its own cells.
But what is worse is that once the researchers stopped giving monkey antiretroviral drugs after treatment, the virus levels of the two monkeys rebounded rapidly.
More unfortunately, the third monkey developed kidney failure and was eventually euthanized. The researchers found a certain number of HIV viruses in some of its tissues, suggesting that none of the three monkeys were "cured" by this treatment.
"These findings suggest that although radiotherapy may reduce the level of HIV, it is not enough to eliminate all cells that store HIV." The researchers said, "The results show that the Berlin case was cured, the bone marrow donor's genetic mutation or It is a graft-versus-host disease that plays a significant role."
The treatment of Berlin cases has been tried in at least two HIV-infected people with lymphoma. However, in these cases, the bone marrow donor does not have a rare mutation in the CCR5 gene. The patient initially appeared to be without the HIV virus, but after a few months the virus appeared again and the patient had to start taking antiretroviral drugs again.
Source: Shell Network
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