The patient, a middle-aged woman of mixed race, was treated with a transplant of stem cells from umbilical cord blood, according to CNN.
She has now been in remission of HIV for 14 months, said scientists.
Researchers, who presented findings at the Conference on Retroviruses and Opportunistic Infections on Tuesday, believe the new stem cell method could potentially treat more people from racially diverse backgrounds than was previously thought possible.
This is because umbilical cord blood does not need to be as closely matched to the recipient as adult cells from bone marrow transplants.
“The fact that she’s mixed race, and that she’s a woman, that is really important scientifically and really important in terms of the community impact,” Dr Steven Deeks, an Aids expert at the University of California, told the New York Times.
The woman is understood to have been diagnosed with HIV in 2013, before receiving a diagnosis of acute myeloid leukaemia four years later.
She underwent high-dose chemotherapy that destroyed her blood cells, before receiving a transplant of stem cells from a family member to boost immunity and replenish her blood cell levels.
The patient then received stem cells through the umbilical cord blood of a newborn baby who was not related to her. The cord blood is said to have featured a mutation making cells resistant to HIV infection.
Just over three years after her 2017 transplant, the patient was able to stop taking HIV medication, called antiretroviral therapy (ART) and about 14 months later, she had no detectable virus in her system.
Researchers said both her cancer and HIV are in remission and the patient is doing well - but it is still too soon to declare for certain that she has been cured of HIV.
According to scientists, the majority of US donors who have the HIV-resistant mutation in their blood are of Caucasian - particularly northern European - descent, limiting options for those who are not white.
Researchers are encouraged by the most recent study, because although the patient is of mixed race heritage, she was still a match for the cell transplant. This suggests there may be a wider pool of people of racially diverse backgrounds who could benefit from this treatment.
Although the study is promising, researchers caution that the treatment may only apply to a small percentage of people living with HIV.
Around 50 people per year in the US living with HIV and blood cancer may benefit from the treatment, Dr. Yvonne Bryson, chief of pediatric infectious diseases at UCLA and the principal investigator of the study, told CNN.
Dr. Marshall Glesby, associate chief of the Division of Infectious Diseases at Weill Cornell Medicine and a member of the research team, agreed, adding: "This is not the type of treatment that would be appropriate for somebody who does not have a medical need to have a transplant."
What is HIV and how many people are living with the virus worldwide?
HIV (Human Immunodeficiency Virus) is a virus which attacks the immune system.
According to the World Health Organization (WHO), 37.7 million people were living with HIV or AIDS worldwide in 2020. Of those, 680,000 people died from HIV-related causes that year.
What treatment is available?
There is currently no cure for HIV but treatment now allows most people to have a normal life expectancy.
The virus stays in the body for life but ART treatment can keep the virus under control and keep the immune system healthy.
HIV medication increases a person’s CD4 (white blood cells that fight infection) count and reduces their viral load. The treatment is now so effective it reduces someone’s viral load to undetectable levels within about six months.
When a patient reaches undetectable levels, this means they cannot pass on the virus and allows a them to maintain a healthy immune system.
However, without medication, people living with HIV can develop AIDS (Acquired Immune Deficiency Syndrome) - the most advanced stage of the infection, in which the immune system can no longer fight infections.
The National Aid Trust says: "AIDS is life-threatening, but if HIV is caught early and is treated, it will not lead to AIDS. If HIV is caught late, it can lead to more complications and could ultimately lead to AIDS."
Those who are HIV-negative can also choose to take PrEP (pre-exposure prophylaxis) drugs, which reduce the risk of getting HIV, before and after sex. It works to block HIV if it gets into a person's body.