- A man became the third person to have been “cured of HIV” after a bone marrow transplant carrying a specific HIV-resistant mutation.
- The CCR5-delta 32 mutation prevents the receptors used by the HIV virus from forming on the surface, effectively denying the virus its doorway to the body. It is this genetic mutation that scientists have utilised to “cure” patients of HIV.
What is CCR5 mutation and how does it fight off HIV?
- HIV (Human Immunodeficiency Virus) mainly attacks the CD4 immune cells in the human body, thereby reducing a person’s ability to fight off secondary infections.
- The CCR5 receptors on the surface of the CD4 immune cells act as a doorway for the HIV virus.
- However, the CCR5-delta 32 mutation prevents these receptors used by the HIV virus from forming on the surface, effectively removing the doorway.
- Only 1 per cent of the people in the world carry two copies of the CCR5-delta 32 mutation – meaning they got it from both their parents – and another 20 per cent carry one copy of the mutation, mainly those of European descent.
- Those with the mutation hence are almost immune to the infection, although some cases have been reported.
Can such transplants solve the HIV crisis?
- With the mutation existing in very few people and nearly 38.4 million people living with HIV across the world, it would be very difficult to find a matching donor in the first place.
- However, even if donors were to become available, experts believe it is highly unlikely that bone marrow transplants can be rolled out for all those with HIV.
- This is because it is a major procedure with high risks associated, especially that of the person rejecting the donated marrow.
- There is also the likelihood of the virus mutating to enter the cells through other mechanisms in such persons.
What are the current treatments for HIV?
- Although there are no cures for the infection at present, the disease can be managed using antiretroviral therapy.
- These medicines suppress the replication of the virus within the body, allowing the number of CD4 immune cells to bounce back.
- Although earlier the drugs were given only to those with low CD4 count under the government’s programme, now the programme supports anyone who has been diagnosed with HIV.
- The drugs have to be taken for life because the virus continues to persist in reservoirs across the body.
- If the drugs are stopped, the virus can again start replicating and spreading.
- When the viral levels are low, the likelihood of a person transmitting the infection is also low.
- If left untreated, the virus destroys a person’s immune system and they are said to be in the Acquired Immunodeficiency Syndrome stage (AIDS) where they get several opportunistic infections that may result in death.
- Although there is no vaccine for HIV, there are Pre-exposure prophylaxis (or PrEP) medicines that can be taken by people at high risk of contracting the infection. PrEP reduces the risk of getting HIV from sex by about 99 per cent.
SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB