Umbilical cord blood cures HIV
A US patient has become the third person in the world, and the first woman, to be cured of HIV, the deadly virus that causes AIDS. The woman, who was diagnosed with leukaemia in 2017, recovered after receiving a stem cell transplant from a donor who was naturally resistant to HIV, The New York Times reported.
The case, presented at the Conference on Retroviruses and Opportunistic Infections in Denver earlier this month, is the first involving umbilical cord blood, a new method that medical experts believe will make HIV treatment more widely available.
What is HIV and how is it transmitted?
Human immunodeficiency virus or HIV is an infection that attacks the immune system by destroying the body’s immune cells called CD4, which help it respond to infection. Once HIV attacks the CD4 cells, it starts replicating and destroying the cells, weakening the body’s immune system and making it more prone to certain “opportunistic infections” that take advantage of the weak immune system.
Bodily fluids such as blood, semen, vaginal fluids, rectal fluids and breastmilk can be carriers for HIV. It can be transmitted through unprotected sex, transfusion of contaminated blood, sharing needles and syringes, and from a mother with HIV to her infant during pregnancy.
Typically, the time between HIV transmission and AIDS diagnosis is 10-15 years, although it may occur sooner.
What do we know about this breakthrough treatment?
In 2013, the mixed-race woman, now known as the ‘New York patient’, was diagnosed with HIV. She began to receive antiretroviral drugs to keep her virus levels low. Four years later, she was diagnosed with leukaemia. As part of her cancer treatment, she received a transplant of umbilical cord blood from someone who had a natural resistance to HIV. Since then, she has not required antiretroviral therapy, researchers presenting her case said.
The blood from the umbilical cord contained a mutation that blocks HIV, The New York Times reported. Significantly, it was sourced from a partially-matched donor. Similar transplant procedures that are done using bone marrow require an exact match.
The patient was part of a US-based study, led by Dr Yvonne Bryson of the University of California Los Angeles (UCLA) and Dr Deborah Persaud of Johns Hopkins University in Baltimore, involving 25 HIV patients from across the country who had received the new type of blood transplant to treat cancer and other life-threatening diseases. As part of this study, patients first undergo chemotherapy to kill off cancerous immune cells before the stem cell transplant.
According to some experts, the new transplant method may be too risky for most people living with HIV, BBC reported.
Why is this significant?
Apart from being a major medical breakthrough, this case is significant for two reasons. First, this was the first time an umbilical cord blood transplant was successfully carried out on an HIV patient. Doctors and researchers have indicated that this approach is likely to make treatment more widely available.
Second, the patient was a middle-aged mixed-race woman. This is significant since the majority of donors in the US are of Caucasian descent. Since this breakthrough treatment only requires partial matches and not exact matches, it opens up treatment options for people from diverse racial backgrounds.
How were the first two HIV patients cured?
Timothy Ray Brown from Berlin was the first person to be “cured” of HIV after receiving a stem cell transplant in 2007. Adam Castillejo from London was the second person in the world to be cured of HIV in 2020. In both cases, the two patients received transplants from donors who have an uncommon gene that gives them protection against HIV.
Unlike in the case of the New York patient, both Brown and Castillejo received adult stem cells as part of bone marrow transplants. While adult stem cells are more difficult to find, umbilical cord blood is more widely available. It also does not require as close a match with the donor.
Both men suffered severe side effects following the bone marrow transplants, including graft-versus-host disease. In fact, Brown nearly died after his transplant.
Meanwhile, the New York patient was discharged from the hospital just 17 days after the procedure and did not develop graft-versus-host disease, her physician, JingMei Hsu, told The New York Times.
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