The HIV virus has disappeared after a stem cell transplant.
A New York woman is the fourth patient to have experienced complete remission of the AIDS virus after a stem cell transplant ‒ stem cells which, in addition to being compatible, have a mutation that prevents the virus from entering them.
As in the three previous cases ‒ Berlin, London and Düsseldorf ‒ the New York patient had blood cancer. After the transplant, which was performed with umbilical cord blood cells, both the cancer and HIV disappeared. In the other three cases, adult stem cells were used.
After 30 months without any trace of the virus or use of antiretroviral drugs, the researchers cautiously speak of “remission and possible cure” of HIV.
“She is currently clinically healthy, cancer- and HIV-free. We’re calling this a possible cure rather than a definitive cure, while we wait for a longer follow-up period”, said Yvonne Bryson, specialist in the Division of Infectious Diseases at the Department of Paediatrics at the University of California, Los Angeles and lead author of the research.
In a virtual press conference, Bryson indicated that while this procedure may not be applicable to all patients with HIV, the results obtained is “good news” which can pave the way for the development of new techniques to implement this whole new therapeutic strategy.
Approximately 38 million people worldwide are living with HIV. HIV infections are currently incurable: in most cases, we simply must accept that we can keep the virus under control through lifelong administration of antiretroviral drugs, which minimize viral load. But the virus is never eliminated, as it usually hides in viral reservoirs, and when drug treatment is interrupted, it awakens from its dormant state.
Stem cell transplant is a highly aggressive technique (mortality can reach 40%) and is intended for patients with blood cancer who do not respond to other therapies. Due to its risks, it is not a procedure that can be implemented with all HIV patients: it is simply unethical to administer these aggressive treatments to patients in order to get rid of the virus when there are in fact effective antiretroviral therapies which are capable of keeping infections under control.
The four patients had blood cancer and had no other alternative but to undergo a stem cell transplant. The therapy consists in emptying the patient’s bone marrow, where haematopoietic stem cells are located, to eliminate the cancer and repopulate it with cells extracted from a compatible donor. Therefore, to kill two birds with one stone ‒ cancer and HIV ‒, donors were sought who, in addition to being compatible, had a specific mutation in their CCR5 gene (CCR5Δ32), which prevents the virus from penetrating cells. The donor’s stem cells eventually replace those of the patient, leading to a reduction in the patient’s blood cancer while offering resistance against HIV.