Posted at 5:00 a.m.
It is really encouraging. Any breakthrough takes us to another step towards total healing.
Gary Lacasse, Executive Director of the Canadian AIDS Society
A drastic increase
In recent years, Canada has seen a sharp rise in cases of the human immunodeficiency virus (HIV), which causes AIDS. “We have suffered drastic increases since 2014, with an increase of around 25%. With the pandemic, unequal access to screening in the country has also manifested itself in an increase in STBBIs,” maintains Mr. Lacasse.
Number of people living with HIV
Source: Government of Canada
2561
Number of new HIV diagnoses in Canada in 2018, compared to 2040 cases in 2014.
Source: Canadian AIDS Society
A chronic illness
The treatments offered to date usually consist of a combination of three antiretroviral drugs taken daily. These drugs do not eradicate the virus, but reduce the viral load in the patient. “It works extremely well, and people have a life expectancy that’s about the same as people who don’t have HIV, but it’s still a chronic disease,” says Dr.r Michel Alary, population health researcher at the CHU de Québec–Université Laval.
17,040
Number of people infected with HIV in Quebec in 2018.
Source: Portrait of sexually transmitted and blood-borne infections (STBBIs) in Quebec, year 2019
An effective transplant
On February 15, scientists announced that a woman of mixed racial origin appears to have been cured of HIV. The patient, who underwent a transplant as part of treatment for leukemia, received stem cells from a newborn baby with a rare genetic mutation that prevents HIV from taking hold. Three months after the transplant, all of the woman’s blood cells were now resistant to HIV. She was able to stop taking her antiretroviral drugs.
Two other cases
PHOTO MANUEL VALDES, ASSOCIATED PRESS ARCHIVES
American Timothy Ray Brown, nicknamed the “Berlin patient”, was the first person in the world to be cured of HIV. Pictured here in March 2019 in Seattle, Mr Brown passed away in September 2020.
This is not the first time that a stem cell transplant has cured an individual with HIV. Two other cases of recovery have been reported worldwide so far. Known as the “Berlin patient” and the “London patient”, the two men received stem cell transplants from bone marrow. Their donors were also carriers of the mutation that makes them resistant to infection.
More diversity
The fact that this third patient, nicknamed the patient from New York, is a mixed-race woman is a great scientific advance, experts believe. Indeed, the mutation being much more common in people of European descent, it is more difficult to find donors for stem cell transplants in non-white patients.
The use of umbilical cord blood, as in the cured patient, does not require finding a donor of similar ethnicity, unlike bone marrow transplants which made it possible to cure the two previous patients, indicates Éric Cohen, professor of virology at the Faculty of Medicine of the University of Montreal. The use of umbilical cord blood therefore opens the way to the healing of more people of various origins.
1%
Researchers estimate that 1% of individuals of northern European descent have the HIV-resistant mutation that has cured all three individuals. However, this mutation is less prevalent in other ethnic groups, including Africans and Asians.
Source: article published in the scientific journal HIV Medicine : “Identification and frequency of CCR5Δ32/Δ32 HIV-resistant cord blood units from Houston area hospitals”.
For better representation
The patient is also the first woman to be diagnosed with long-term remission. “This is important and it sends a very good message, considering that only around 11% of participants in clinical trials for cures are women. It is important that there is a good representation, even almost equal, to ensure that the treatments are generalizable”, maintains Mr. Cohen.
25%
Of the 62,050 Canadians living with HIV at the end of 2018, 1 in 4 (25%) were women.
Source: Government of Canada
A risky procedure
Could stem cell transplantation by immunized donors be generalizable to all patients? No, say the experts without hesitation. The transplant is a very risky procedure, with a mortality rate of 10% to 20%, says the Dr Alary. It is therefore only considered in people with HIV who also have cancers and other diseases.
PHOTO ARCHIVES PRESS
Éric Cohen, professor of virology in the department of microbiology, infectiology and immunology of the faculty of medicine at the Université de Montréal
All the same, these are three cases that stimulate research, because it proves that we are capable of curing patients. It sheds light on strategies to eventually find treatments that carry less risk.
Éric Cohen, professor of virology in the department of microbiology, infectiology and immunology of the faculty of medicine at the Université de Montréal
The future
Experts hope that this breakthrough will lead to a cure for the disease. “We would like to mimic this approach, without the risks it may entail. I am very confident that we will get there, ”says Professor Cohen. Until then, the Dr Alary recalls the importance of good screening and generalized access to treatment.