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Stem cell research is considered promising in the search for treatment options for HIV
Photo: Andrew Brookes/Getty Images/Westend61
A US leukemia patient has become the first woman and third person in the world to appear to have been cured of HIV.
She was treated with a new form of stem cell therapy, scientists reported Tuesday at a conference in Denver.
The middle-aged, multi-racial woman was diagnosed in June 2013 as being HIV positive.
Antiretroviral drugs kept the virus under control in her body.
In March 2017, she was diagnosed with myeloid leukemia, a cancer that starts in blood-forming cells in the bone marrow.
As part of a study, the woman was treated around six months later with stem cells from umbilical cord blood, primarily to fight the cancer.
Since then she has been virus-free and no longer needs anti-HIV medication, the doctors said.
The woman is said to be the first HIV patient to be treated with stem cells from umbilical cord blood.
The two patients previously cured of HIV with stem cell therapy were male.
The first, Timothy Ray Brown, also known as the "Berlin Patient," was virus-free for twelve years after treatment.
In 2020, Brown died of cancer.
There was another success story three years ago: Adam Castillejo's HIV virus is also no longer detectable after the stem cell transplant.
Both men were treated with stem cells from the bone marrow, also called a bone marrow transplant.
The donors had a special mutation called Delta 32. This means that the cells do not produce a CCR5 receptor, which most HI viruses need to attach to a cell in which they could multiply.
So the donors are inherently immune to the virus.
Scientists believe that after the transplant, recipients take on this trait and become immune to HIV as well.
Only around 20,000 stem cell donors worldwide carry the special mutation, most of them come from northern Europe.
Stem cell therapy is highly risky
With a stem cell transplant, new blood stem cells grow in the body.
This renews the immune system.
In the case of a stem cell transplant, the tissue characteristics of the stem cell donor and the stem cell recipient usually have to match.
This is extremely rare.
In addition, stem cell therapy remains a high-risk treatment that is usually only an option for cancer patients when all other treatment options have been exhausted.
Therefore, in the future, physicians will likely continue to rely on the classic approach of keeping the HI virus in check with antiretroviral drugs and thus suppressing the outbreak of AIDS in the long term for the vast majority of those affected.
The two treated men also suffered serious side effects after the bone marrow transplant, such as graft-versus-host disease, in which the donor's cells attack the recipient's body.
Timothy Ray Brown nearly died after treatment.
Stem cells from umbilical cord blood, like those used in the patient in the USA, have the advantage that they are usually better tolerated and the body is less likely to reject them than with stem cells from the bone marrow, for example.
A complete match between donor and recipient is therefore not absolutely necessary.
This could be an advantage for people from different backgrounds.
Because in the global stem cell databases, predominantly white people are registered.
While patients usually have to wait a long time before a suitable bone marrow donor is found who has the same characteristics as their own, the leukemia patient was treated with stem cells from a donor who was only partially able to do so.
Since the therapy takes around six weeks to take effect, the woman also received blood cells from a first-degree relative.
These semi-matched cells supported their immune system until the umbilical cord cells became dominant.
That made the transplant less dangerous, her doctors reported.
According to the team, she tolerated the treatment well.
She left the hospital just 17 days after the transplant, reports the New York Times.
She has not developed graft-versus-host disease.
The woman continued to take antiretroviral drugs for 37 months.
After she stopped taking them, neither HIV nor antibodies against the virus were detectable in her blood – not even 14 months later.
"The fact that the patient is multiracial and female is both very important to science and has important implications for society," Steven Deeks, an AIDS researcher at the University of California, told the New York Times « according to.
It is believed that HIV infection progresses differently in men and women.
But while women account for around half of all HIV cases worldwide, only about eleven percent of the participants in HIV studies are female.
Deeks sees the healing success as groundbreaking, but does not believe that stem cell therapy will soon be commonplace for HIV patients.
Sharon Lewin, President of the International Aids Society, expressed more confidence in a statement.
"This is now the third report of a cure and the first in a woman living with HIV," Lewin said.
Bone marrow transplants, as performed in the male patients, are not a viable strategy to cure most people with HIV.
But the woman's case shows that a cure from HIV is possible and the method could be a viable strategy for it.
"The three cases of a cure through stem cell therapy help to learn more about the different components that play a role in transplantation," says Lewin.
Around 38 million people worldwide are currently living with HIV.
About three quarters of them receive antiretroviral drugs that control the virus in order to suppress the outbreak of AIDS in the long term.
However, they cannot completely defeat the virus.
Scientists have therefore been researching treatment options for the disease for years.
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