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Context: Some people of African descent possess a gene variant that likely controls human immunodeficiency virus (HIV), lowering their risk of transmitting the virus and delaying the advancement of their illness, according to a new study.

Findings on Gene CHD1L and HIV’s Relation

• Researchers analysed the DNA of almost 4,000 people of African ancestry living with HIV-1 and found a gene variant CHD1L on chromosome 1.
• People carrying this variant had a low viral load. This lowers their risk of spreading the virus and slows the progress of their illness.
• They infected these cells with HIV. They found that the virus made more copies of itself when CHD1L was turned off in immune cells called macrophages.
• But there was no change in T cells, another type of immune cell. Most HIV, according to the researchers, replicates in T cells. However, research has also shown that macrophages can sustain HIV replication in the absence of T cells.
• The link between HIV replication in macrophages and viral load is particularly interesting and unexpected.

About CHD1L and HIV

• The gene named Chromodomain Helicase DNA Binding Protein 1 Like (CHD1L), contains information to make proteins that allow the body to repair DNA damage.
• A variant of the CHD1L gene is specifically present in the African population and it has been linked to the reduced viral load (amount of HIV in the blood) of the most common and virulent type of HIV, called HIV-1 (more common and severe retrovirus compared to HIV-2).
• The researchers said between 4 per cent and 13 per cent of people of African origin could be carrying this particular variant.

About HIV

• 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.
• Therefore if HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome).

Transmission:

• 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.

Vaccines:

• There's no vaccine to prevent HIV infection and no cure for AIDS. Protecting oneself from infection is the way ahead.

Prevalence of HIV

• HIV-1 affects an estimated 7 million people worldwide. Despite antiretroviral therapy bringing down annual HIV cases, the decline has slowed substantially since 2005.
• In 2021, for instance, some 1.5 million people contracted the infection and 650,000 people died from AIDS-related illnesses despite improvements in treatment.
• The Government of India estimates that about 2.40 million Indians are living with HIV (1.93 ‐3.04 million) with an adult prevalence of 0.31% (2009).
• Annual new HIV infections in India have declined by 48% against the global average of 31% and annual AIDS-related deaths have declined by 82% against the global average of 42% (the baseline year of 2010).

Government initiatives

• The National AIDS Control Programme (NACP), launched in 1992, is being implemented as a comprehensive programme for the prevention and control of HIV/AIDS in India.
  • The National AIDS Control Board (NACB) was constituted and an autonomous National AIDS Control Organisation (NACO) was set up to implement the project.
  • The first phase focused on awareness generation, setting up surveillance systems for monitoring the HIV epidemic, and measures to ensure access to safe blood and preventive services for high-risk group populations.
• In 1999, the 2nd Phase of “The National AIDS Control Project (NACP II)” was launched with World Bank credit support.
  • The objectives of NACP II: to reduce the spread of HIV infection in India, and to increase India’s capacity to respond to HIV/AIDS on a long-term basis.
  • Adoption of National AIDS Prevention and Control Policy (2002).
• The 3rd phase of the national programme (NACPIII) was launched in 2007
  • NACP-III aimed at halting and reversing the HIV epidemic in India over its five-year period by scaling up prevention efforts among High-Risk Groups (HRG) and General Population and integrating them with Care, Support & Treatment services.
• In 2012, the 4th Phase of the National AIDS Control Project (NACP IV)” was launched.
  • It aims to reduce new infections by 50% (2007 Baseline of NACP III).
  • Provide comprehensive care and support to all persons living with HIV/AIDS and treatment services for all those who require it.

Treatments available

• 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.
• 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.

Way ahead

• There is a need to increase free HIV Prevention, detection and treatment services in facility and community settings to high-risk, vulnerable and other ‘at-risk’ populations and PLHIV without any stigma and discrimination promoting equity and inclusiveness.
• The community system strengthening through formal and informal engagement with an emphasis on the decentralised model of district-level programme monitoring and the community feedback loop is the need of the hour.
• Special attention to most at-risk populations, youth, and pregnant women offering a comprehensive package of services should be given.
• The community should be engaged in the design, concurrent appraisal and feedback to the project for providing strategic guidance and mid-course corrections.

PRACTICE QUESTION Q. Consider the following statements about CHD1L gene: The gene named Chromodomain Helicase DNA Binding Protein 1 Like (CHD1L), contains information to make proteins that allow the body to repair DNA damage. A variant of the CHD1L gene is specifically present in the African population It has been linked to the reduced viral load of the most common and virulent type of HIV, called HIV-1. How many of the above  statements are correct? 1 and 2 only 1 and 3 only 2 and 3 only All are correct Ans: D

https://www.downtoearth.org.in/news/africa/gene-variant-in-people-of-african-origin-helps-control-hiv-says-study-90974