US scientists report third case of HIV remission from stem cell treatment

16 Feb 2022

HIV-infected H9 T cell. Image: National Institute of Allergy and Infectious Diseases

Scientists believe patients could develop an immune system that is resistant to HIV with a novel stem cell transplant.

US scientists reported that a woman living with HIV has had no detectable levels of the virus for 14 months after receiving a cord blood stem cell transplant. This makes her the first woman and the third person known to have entered HIV remission following a stem cell treatment.

Cord blood is the blood that remains in the placenta and umbilical cord following a birth and is full of hematopoietic stem cells. These can turn into any kind of blood cell and can be used to treat blood disorders, immune deficiencies, metabolic diseases and some cancers, according to Harvard Health Publishing.

Future Human

A US observational study had been examining the outcomes of 25 people living with HIV who underwent a cord blood stem cell treatment for cancer, hematopoietic disease or other underlying disease.

In these cases, the stem cells had a unique genetic mutation that lacked CCR5 co-receptors, which is what HIV uses to infect cells. By killing off the cancerous cells with chemotherapy and then transplanting stem cells with this mutation, scientists have theorised that people living with HIV can develop a HIV-resistant immune system.

The woman whose case was reported by US scientists yesterday (15 February) had been on antiretroviral therapy (ART) for HIV for four years before receiving a leukaemia diagnosis. Prior to the stem cell treatment, the scientists said her HIV was “well controlled but detectable”.

In 2017, she received a transplant of cord blood stem cells along with adult donor cells from a relative to boost her recovery. After 100 days, she had fully engrafted with the stem cells and had no detectable trace of HIV. More than three years (37 months) after the transplant, she stopped ART.

The study team reported that no HIV was detected in her system for 14 months, except one detection of trace amounts 14 weeks after stopping ART.

Cord blood is more widely available than the adult stem cells used in the previous two HIV remission cases. There also does not need to be as close of a genetic match to the patient, which means it could help treat more people of diverse racial backgrounds, The New York Times reported.

The researchers presented some of their findings at the Conference on Retroviruses and Opportunistic Infections. The research was conducted at the International Maternal Pediatric Adolescent AIDS Clinical Trial Network, funded by the US National Institutes of Health.

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Leigh Mc Gowran is a journalist with Silicon Republic