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The Düsseldorf patient, a 53-year-old German man, has been labelled as the third person to have been "cured of HIV (Human Immunodeficiency Virus)". Even four years after quitting the medication, the virus is still undetectable in his body. This has been made possible with a bone-marrow transplant from a person carrying a specific HIV-resistant genetic mutation.

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What is this genetic mutation and can it put a stop to the HIV virus once and for all?

Others who became HIV-free

Timothy Ray Brown, referred to as the Berlin patient, got two stem cell transplants in 2007 and 2008 to cure his blood cancer, and as a result, he became the first person to successfully overcome HIV. His physicians chose a donor with two copies of the CCR5-delta 32 genetic mutation since the mutation is known to render carriers nearly resistant to HIV. He was diagnosed with HIV, thus the donor was chosen by his doctors. Until his death in 2020 from cancer, he never had HIV, as reported by the Indian Express. 

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Years later, researchers reported similar results in Adam Castillejo, a patient from London, who underwent the same treatment for the first time in 2019. Four years after he stopped using the anti-retroviral medications that regulate the amount of the virus in the body, the Düsseldorf patient, who also received a transplant for blood cancer, has continued to be HIV-free.

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In 2022, there were two further cases of "The City of Hope patient" and "New York patient." Dual stem cell treatment, which uses stem cells from both an adult and a neonate's umbilical cord to complete the transplant in the New York patient, is less rigorous in its HLA matching requirements. This is crucial because it might facilitate the transplantation of CCR5-delta 32 in individuals of different races.

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CCR5 mutation and how does it work against HIV?

The CD4 immune cells in the human body are the primary targets of HIV, which makes it harder for a person to fend against secondary infections. The HIV virus enters the body through the CCR5 receptors on the surface of CD4 immune cells. However, the CCR5-delta 32 mutation blocks the formation of these surface-bound HIV viral receptors, by effectively closing the passage, according to the National Centre of Biotechnology Information. 

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Just one per cent of the world's population has the CCR5-delta 32 mutation in two copies, which means they acquired it from both parents. 20 per cent of people, mostly those of European heritage, have the mutation in one copy. Those who carry the mutation are therefore almost resistant to the virus.

Are transplants a solution to the HIV crisis?

Finding a compatible donor in the first instance would be extremely challenging given the mutation's rarity and the almost 38.4 million individuals living with HIV worldwide, according to the World Health Organisation (WHO). The donor pool for many, especially those from nations with high HIV prevalence, reduces even more when the mutation occurs mostly in Caucasians.

Yet, experts think it is extremely improbable that bone marrow transplants could be made available to everyone with HIV, even if donors were to become available. This is due to the fact that it is a significant surgery with significant dangers, particularly the chance of the recipient rejecting the given bone marrow.

Also, there is a chance that the virus will evolve and find new ways to infiltrate cells.

What are the currently available treatments for HIV?

Despite the fact that there are currently no treatments for the infection, antiretroviral medication can be used to control the disease, according to the Centre for Disease Control and Prevention. These drugs prevent the virus from replicating within the body, enabling the number of CD4 immune cells to increase once more. Although the government's programme used to solely provide medications to people with low CD4 counts, it now supports anybody who has been diagnosed with HIV.

As the virus is still present in the body's reservoirs, the medications must be taken for the rest of one's life. The virus can once more begin multiplying and spreading if the medications are stopped. It is less likely for someone to spread the virus when viral levels are low.

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