Umbilical blood stem cell transplant puts woman in HIV remission
A woman is in remission for HIV after she received HIV-resistant stem cells from umbilical cord blood to treat her leukaemia
The woman, known as the New York patient, has been clear of detectable HIV since 2017, after she received HIV-resistant stem cells that had been harvested from umbilical cord blood to treat her leukaemia. Stem cells are produced by bone marrow and can turn into different types of blood cells.
Several people have previously gone into remission from HIV after receiving stem cells from adult donors who carry two copies of a naturally occurring mutation of the CCR5 gene. This delta 32 mutation prevents the virus from entering and infecting healthy cells.
With any stem cell transplant, recipients can only receive donations from people with matching tissue types to reduce the risk that their immune system will attack the transplanted tissue.
Since tissue types are inherited, a person’s ethnicity influences their ability to find a match. Having two copies of the CCR5 mutation is rare, existing in only around 1 per cent of people of northern European ancestry and being even rarer in other populations.
To overcome the lack of suitable adult donors, doctors carried out a study where they infused umbilical cord blood into the New York patient, who identifies as mixed race.
She also received stem cells from a relative. Umbilical cord blood can contain fewer stem cells than adult blood so mixing it with stem cells from a relative gives the cord blood a “kick start”, Yvonne Bryson at the University of California, Los Angeles, who co-led the study, said in a statement.
Using umbilical cord blood makes it easier to find transplant matches, as large repositories of frozen samples have been donated by people who gave birth in hospitals, says Jingmei Hsu at the New York Presbyterian Hospital. “Having a bank [of cord blood] really opened the door to help more patients,” she says.
Most people with HIV can lower the amount of the virus in their blood to undetectable levels by taking antiretroviral drugs, which stop the virus from replicating in their body.
Stem cell transplants would therefore only be considered for people with HIV who also have advanced blood cancer, which can be treated with the procedure. The New York patient no longer requires antiretroviral drugs and is also in remission for her leukaemia.
https://www.newscientist.com/article/2364804-umbilical-blood-stem-cell-transplant-puts-woman-in-hiv-remission/
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