A New Yorker is the first woman possibly cured of HIV thanks to a transplant of umbilical cord blood stem cells resistant to that virus, which were combined with stem cells from a close relative to increase the chances of success.
The so-called New York patient also suffered from a type of leukemia, which made a bone marrow transplant necessary, and she has been virus-free since 2017, a period that, due to other similar cases, is considered reasonable to consider that she may be cured.
This case was reported a year ago at a medical congress, but until now the results had not been published in any scientific journal, which is what the team, headed by the University of California (UCLA) and Johns Hopkins, is doing today in Cell.
Today four people consider themselves cured of HIV, patients from Berlin, London, Düsseldorf and now New York. All also suffered from leukemia that required a bone marrow transplant, a risky intervention that is only indicated in hematological cancers.
The case of the New York patient, a middle-aged woman who identifies as “racially mixed”, has several peculiarities compared to the others, the first to undergo a transplant of HIV-resistant stem cells from cord blood umbilical cord and not from a matched adult donor.
The team believes that the treatment has given “satisfactory long-term results,” the study indicates, and that the use of umbilical cord blood stem cells increases the chance of curing HIV in people of all racial origins.”
“The HIV epidemic is racially diverse, and it is extremely rare for people of color or mixed race to find a sufficiently matched adult unrelated donor,” explained Yvonne Bryson of UCLA and co-director of the study.
However, the use of umbilical cord blood cells “expands the opportunities for people of diverse ancestry living with HIV who require transplantation for other conditions to achieve a cure.”
The patients in Berlin, London and Düsseldorf received stem cell transplants from matched adults who carried two copies of the CCR5-delta32 mutation, a natural mutation that confers resistance to HIV by preventing the virus from entering and infecting cells.
Only about 1% of whites are homozygous for the CCR5-delta32 mutation and it is even rarer in other populations, limiting the possibility of transplanting it to patients of color, as stem cell transplants often require a great compatibility between donor and recipient.
These conditions made it almost impossible to find an adult donor with the aforementioned mutation and compatible with the patient, so in 2017 the team transplanted stem cells carrying CCR5-delta32/32 from stored umbilical cord blood to try to simultaneously cure cancer and HIV.
In addition, these cells were infused with stem cells from one of the patient’s relatives to increase the chances of success of the procedure.
“With umbilical cord blood, you don’t have as many cells and they take a little longer to populate the body after infusion,” but using a mixture of stem cells from a relative and cord blood “gives a boost to the cell’s umbilical cord blood,” Bryson said.
The transplant managed to put both HIV and leukemia into remission, which lasted for more than four years. Thirty-seven months after the transplant, the patient was able to stop taking the anti-HIV medication. The doctors who follow her say that she has not contracted HIV for more than 30 months since she stopped antiviral treatment (at the time the study was written, only 18 months had passed).
“Stem cell transplants with CCR5-delta32/32 cells offer a two-for-one cure for people living with HIV and blood cancers,” said Deborah Persaud, from Johns Hopkins University and co-director of the study, quoted by Cell.
However, due to the invasiveness of the procedure, stem cell transplants (both with and without the mutation) are only being considered for people who need a transplant for other reasons, and not to cure HIV alone, a disease for which there is medication.
The study also highlights the importance of having CCR5-delta32/32 cells in stem cell transplants for patients with HIV, since all the cures, up to now, “have been with this population of mutated cells, and the studies in which New stem cells that have been transplanted without this mutation have not been able to cure HIV,” Persaud stressed.
