Human immunodeficiency virus or HIV attacks the immune system by destroying CD4 immune cells that help it respond to the infection.
A US patient has become the first-ever woman — the third person in the world — to be cured of HIV, the AIDS-causing deadly virus. The New York Times reported that the woman, who was diagnosed with leukaemia in 2017, recovered following a stem cell transplant from a donor naturally resistant to HIV. The case, which was presented earlier this month at the Conference on Retroviruses and Opportunistic Infections in Denver, is the first involving umbilical cord blood. This new method will make HIV treatment more widely available, medical experts believe.
HIV AND ITS TRANSMISSION
Human immunodeficiency virus or HIV attacks the immune system by destroying CD4 immune cells that help it respond to the infection. Once the virus attacks the CD4 cells, it replicates and destroys the cells, weakening the immune system and making it prone to “opportunistic infections” that take advantage of a weakened immune system.
HIV can be carried by bodily fluids such as semen and vaginal fluids, blood, breastmilk, and rectal fluids. The virus can be transmitted through transfusion of contaminated blood, unprotected sex, sharing needles and syringes, and from a HIV-positive mother to her infant during pregnancy.
Typically, AIDS diagnosis takes around 10-15 years after HIV transmission, although, in some cases, it may occur sooner.
In 2013, doctors diagnosed the mixed-race woman, known now as the ‘New York patient’, with HIV. She started receiving antiretroviral drugs to keep the virus levels low. She was diagnosed with leukaemia four years later. As part of her cancer treatment, she received umbilical cord blood from someone with a natural resistance to HIV. Since then, she has not needed antiretroviral therapy, researchers said.
The blood from the umbilical cord contained a mutation blocking HIV, The New York Times reported. In a more significant development, the blood was sourced from a partially-matched donor. Such transplant procedures done using bone marrow require an exact match.
The patient was part of a study, led by University of California Los Angeles’ Dr Yvonne Bryson and Johns Hopkins University’s Dr Deborah Persaud, involving 25 HIV patients from across the US who had received the new type of blood transplant for cancer and other life-threatening diseases. As part of the study, patients first undergo chemotherapy to kill off the cancerous immune cells prior to the stem cell transplant.
Some experts told the BBC that the new transplant method might be too risky for most people with HIV.
Major medical breakthrough apart, two reasons make this case significant. First, this was the first time that an umbilical cord blood transplant was carried out successfully on an HIV patient. Doctors and researchers indicated that this approach could make HIV treatment more widely available.
Second was the patient being a middle-aged woman of mixed-race. This development is significant since the majority of US donors are of Caucasian descent. With this treatment only requiring partial matches, it opens up treatment avenues for people from diverse racial heritage.
THE FIRST TWO ‘CURED’ HIV PATIENTS
Berlin native Timothy Ray Brown was the first person to be ‘cured’ of HIV after he received a stem cell transplant in 2007. Adam Castillejo from London was the second person when he was cured in 2020. In both the cases, the two patients received transplants from donors with an uncommon gene giving them protection against HIV.
Unlike the New York patient, both Castillejo and Brown received adult stem cells as part of bone marrow transplants. While adult stem cells are difficult to find, umbilical cord blood is more widely available and does not require a match.
Both men, however, suffered severe side effects following the transplants, including graft-versus-host disease.
The New York patient, on the other hand, was discharged 17 days after the procedure and did not suffer from graft-versus-host disease, The New York Times reported.