Why is it so difficult to find a cure for HIV and AIDS?

Curing AIDS is generally taken to mean clearing the body of HIV – the virus that causes AIDS. The virus replicates itself by inserting its genetic code into human cells and hijacking its replication machinery. The HI virus targets CD4 cells which are key role players in the body’s defence against infection and cancers. Depending on the type, antiretroviral drugs interfere with several of the steps in the replication process, which is why the drugs are so effective at reducing the amount of HIV in a person’s body. During treatment, the concentration of HIV in the blood often falls so low that it cannot be detected by the standard test, known as the viral load test.

Unfortunately, not all infected cells behave the same way, as demonstrated by the phenomenon of “resting”CD4 cells. Once infected with HIV, these cells, instead of producing new copies of the virus, lie dormant for many years, rendering the drugs targeting replication useless. Importantly, current therapies cannot remove HIV’s genetic material from these cells. This means that even if someone takes antiretroviral drugs for many years they will still have some HIV hiding in various parts of the body. A cure for HIV must therefore either remove every single cell or control HIV effectively by keeping the virus dormant. Unfortunately the virus eventually develops mutations in its genes which make the drugs ineffective, and the virus can then begin replicating uncontrollably.

REPUTABLE RESEARCH ON CURING HIV AND AIDS INCLUDES:

  • The possibility of a "functional cure" by keeping the virus dormant.
  • Bone marrow transplants. One particular transplant – given as a treatment for leukaemia – used cells from a donor with a rare genetic mutation known as Delta 32 that confers resistance to HIV infection. Twenty months after the procedure, researchers reported they could find no trace of HIV in the recipient’s bone marrow. However, bone marrow transplantation is too dangerous and costly for widespread use as a cure.
  • Gene therapy. This is viewed as having the potential to engineer HIV control by introducing genes into cells which confers resistance to the virus. However, because of the invasive nature of stem cell treatment and the fact that the body is likely to attack donor cells and destroy them, it is not viable for the majority of people living with HIV.
  • Antibodies. All people living with HIV naturally respond to the virus by producing antibodies but most people’s antibodies are unable to kill the virus. The immune systems of a small minority, however, produce “broadly neutralising antibodies’, which can kill or neutralise a wide range of HIV strains. Earlier this year (2014) a research team found and identified these antibodies in a South African woman before cloning them in a laboratory. Despite providing hope for gene therapy in other people, these antibodies were unable to destroy the virus within her own body. Like with the drugs, the HI virus eventually evades the immune system by developing mutations which prevent the antibodies from recognising and attacking it.

Despite all of this, it is often argued that there will be no single cure for HIV/AIDs, and overcoming the virus will need to involve a multi-faceted approach.

Source: www.avert.org – revised by Dr Cameron Meyer, Business Manager, Intercare Centre for Lifestyle Management.

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