Why in news?
- An HIV-positive patient in London has become the second known adult worldwide to be cleared of the AIDS virus after he received a bone marrow transplant from an HIV-resistant donor.
- His case is similar to the first known case of a functional cure of HIV in Berlin; the patient underwent similar treatment in Germany in 2007 which also cleared his HIV.
- In both the cases, donor had a genetic mutation known as ‘CCR5 delta 32’, which confers resistance to HIV.
HIV and AIDS: in brief
- Human Immunodeficiency Virus (HIV) is a virus that attacks the immune system, our body’s natural defence against illness.
- If HIV is left untreated, a person’s immune system will get weaker and weaker until it can no longer fight off life-threatening infections and diseases.
- Acquired Immune Deficiency Syndrome (AIDS) is a set of symptoms and illnesses that happen at the final stage of HIV infection, if left untreated.
How the HIV attacks the immune system?
- After a person is infected with HIV, the virus attaches itself to the body’s immune cells in the hopes of producing more virus particles.
- In the acute stages of infection, the virus destroys a lot of immune cells and produces many virus particles, leading the immune systeminto overdrive in trying and warding off infection.
- Later, the virus enters into a period of clinical latency, this time the virus is active but reproduces minimally.
- In the last stage of infection, AIDS, the number of immune cells drops well below the normal level.
- The body’s immune system is left critically damaged, leaving the person susceptible to illness.
About CCR5-delta 32 mutation
- CCR5-delta 32 is a genetic mutation responsible for HIV resistance, which hampers HIV’s ability to infiltrate immune cells.
- CCR5 co-receptor is present outside the cells and acts like a door that allows HIV entrance into the cell.
- The CCR5-delta 32 mutation acts like a door lock which prevents HIV from entering into the cell.
- About 1% of people who are descendents from Northern Europeans, are homozygous carriers of the mutated gene (they inherited a copy from both of their parents). Thus, they are immune to HIV infection.
- Since the CCR5-delta 32 is tied primarily to the Eurasia region, the mutation has not been found in Africans, East Asians etc.
- These successful cases marks critical moments in the search for an HIV cure and give hope that scientists will one day be able to cure AIDS.