CCR5 Receptors – Can they be a cure for HIV?

Why in news?

A man from Germany, has become at least the third person to have been cured of HIV with the virus not being detectable in his body even 4 years after stopping the medicine.

What is the Human Immunodeficiency Virus (HIV)?

• Type - HIV is a lentivirus, which is a sub-classification of the retrovirus.
• AIDS - It causes the HIV infection which over time leads to Acquired Immunodeficiency Syndrome (AIDS).
• AIDS is a deadly condition in which the affected person’s immune system fails, leading to the spread of life-threatening infections and cancers in his body.
• HIV demolishes a particular type of WBC (White Blood Cells) and the T-helper cells.
• Transmission - HIV infection can occur by the transference of blood, breast milk, vaginal fluid, semen, or pre-ejaculate.

What is CCR5 mutation?

• HIV mainly attacks the CD4 immune cells in the human body.
• The CCR5 receptors on the surface of the CD4 immune cells act as a doorway for 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.
• Those with the mutation are almost immune to the HIV infection, although some cases have been reported.

What are the challenges in transplanting these receptors in HIV Patients?

• Heavy load of HIV Patients - Mutation exist in very few people and nearly 38.4 million people living with HIV across the world.
• It is very difficult to find a matching donor.
• Restricted donor pool - The mutation occurs mainly among Caucasians, and restricted the donor pool further.
• High risk - Bone marrow Transplant involves high risks, 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.
• Anti-Retroviral Therapy - These medicines suppress the replication of the virus within the body, allowing the number of CD4 immune cells to bounce back.
• 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.
• PrEP - 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%.

References

1. Indian Express – Third patient is cured of HIV
2. Wion – Duesseldorf patient cured of HIV
3. DW – Germany's 'Düsseldorf Patient' cured of HIV