Status of HIV 'cure'? It's complicated

HIV 'cure'? It's complicated

On 15 February 2022, a patient in the United States was reported as the first woman cured of HIV. She becomes the third person believed to have been cured of the virus in the 40-year history of the disease. While the medical fraternity and AIDS society praise the possibility of a cure, they cautioned against calling the procedure a cure.  Here’s what you should know about why that is.

 

How was the HIV cure was discovered?

The now dubbed “New York” patient joins two other patients in the past decade who have been functionally cured of HIV. The three patients shared more than their HIV status in common. All three were diagnosed with life-threatening blood cancers. To treat the cancers, the patients undergo chemotherapy or radiation which destroy blood-forming stem cells. A stem cell transplant is then needed to replace these cells.  

The replacement cells used had a key element, an HIV-resistant variant. It was through this transplant of cells with this variant after cancer treatment that the patients were ‘cured’ of HIV. (And were also cured of their cancers)

 

What’s new about this HIV cure?

HIV typically enters the body because of receptors in cells known as CCR5. There are individuals who carry an inherent genetic mutation of CCR5 that can resist HIV from entering the body. This mutation is known as CCR5Δ32. Very few of these individuals exist and most are from a Caucasian and male demographic. HIV treatment studies have therefore been focused on this demographic because donors came from this demographic. Until now.

 

A team of doctors at Weill Cornell developed a transplant to expand cancer treatment options for people with blood malignancies who lack human leukocyte antigen (HLA)-identical donors. This transplant done in New York patient opened a new avenue of research:

  • HIV treatment using the genetic mutation expanded to the female and non-Caucasian demographic, broadening the scope to others
  • Compared with adult stem cells needed in a bone marrow transplant, cord blood is more adaptable and requires less of a human leukocyte antigen (HLA) match in treating cancer
  • Stem cell transplants using cord blood reduces the risk of graft versus host disease, an inflammatory reaction where the donor cells attack the new recipient’s body

 

The New York patient had two stem cell donors, one from the umbilical cord blood of an infant and the other from an adult donor. Both donors were only a partial HLA match to the woman, but the combination of the two transplants allowed for this as both had the HIV-resistant genetic mutation.

The effect of stem cells transplants from umbilical cords takes longer and makes the patient can be vulnerable to infection hence the use of additional stem cells. The additional stem cells from the adult donor were from a relative and used to reduce infectious complications

 

Can this cure be used on other patients in the future?

Though this gene therapy procedure gives hope to more than 37 million HIV patients, the procedure used is intended for the treatment of cancer, not HIV. If an HIV-positive patient were to develop a blood cancer that needs stem cell therapy, this novel approach is certainly a multi-beneficial and more gentle option than bone marrow transplants.

Dr. JingMei Hsu, the New York patient’s physician at Weill Cornell Medicine, cautions against this procedure for those patients living healthily with HIV. In a New York Times article, she 

states that “The combination of cord blood and her relative’s cells might have spared her much of the brutal side effects of a typical bone marrow transplant.”

The two other patients who were cured using stem cell therapy via bone marrow suffered from side effects such as extreme weight loss, hearing loss, infections, and near death.