It is a little known fact that some people are born with an immunity to HIV/AIDS. Such a person could be exposed to infection again and again and yet not contract the illness. They are the lucky ones. But more than that, they could also be the ones who hold the cure for the world. Some suggest that Elton John may be one such person who is immune to HIV. I today’s post, I look at what causes someone to be immune to HIV and whether Sir Elton John might have this special gift…
HIV – the ‘AIDS virus’ – is a cunning beast. Unlike most viruses that attack us, and get killed off by the immune system pretty pronto, HIV manages to survive inside us. The virus particle attaches onto and wriggles inside the body’s white blood cells – the very agents designed to protect us. Then, by attacking them from the inside, the immune system is gradually worn down to the point that it is exhausted and can no longer deal with everyday infections. This is called AIDS, and we all know where the story ends.
HIV immunity – a lucky genetic mistake
But by an odd quirk of nature and evolution, about one percent of white Europeans (fewer in other ethnic groups) have a genetic ‘defect’ that makes their white blood cells different. For these people, HIV does enter the blood but then doesn’t get any further. In these people, the virus particle cannot stick onto white blood cells well enough to burrow inside.
Like Velcro, HIV uses tiny ‘hooks’ to cling onto the outside of white blood cells. In people who are genetically immune to HIV, one such ‘hook’ – a protein called CCR5 – is ‘broken’. Unable to cling on, the microscopic HIV just slides off the cell, rendering it impotent.
The circle of life
Most people who are born with HIV immunity are unaware that they have it. The closest someone will ever normally come to knowing they are immune is when sexual partners are succumbing to HIV/AIDS but they don’t have it.
Sir Elton John was recently quoted speaking about how HIV/AIDS had impacted his life:
‘By all rights I shouldn’t be here today. I should be dead – six foot under in a wooden box… I should have contracted HIV in the 1980s and died in the 1990s, just like Freddie Mercury, just like Rock Hudson. Every day I wonder, how did I survive?’
Of course, without a genetic test it is not possible to know whether he is immune or just got lucky. Whatever the truth is, Elton John’s life, music and charity work gives a great many people hope. Many researchers are examining the whys and wherefores of HIV immunity in the hope of finding an ultimate cure or vaccine. If nothing else, that gives me hope.
Thanks for reading – all opinions expressed are my own. Feel free to add your thoughts in the comments below.
Footnote: HIV drugs now and not yet…
A CCR5-delta-32 double mutation is the name given to the genetic difference present in those with HIV immunity. Some anti-HIV drugs have tried to do something similar to stop infection by blocking HIV from attaching to the CCR5 protein on white blood cells. None, however, have provided a cure. It is feasible though that future gene therapy could one day ‘give’ someone the CCR5-delta-32 double mutation and so render them completely immune to HIV.
Wired Magazine: Genetic HIV Resistance Deciphered (a good and thorough explanation of HIV resistance/immunity)
University of California – Los Angeles. “Gene-based stem cell therapy specifically removes cell receptor that attracts HIV.” ScienceDaily. ScienceDaily, 28 February 2010.
Shimizu, S., Hong, P., Arumugam, B., Pokomo, L., Boyer, J., Koizumi, N., Kittipongdaja, P., Chen, A., Bristol, G., Galic, Z., Zack, J., Yang, O., Chen, I., Lee, B., & An, D. (2009). A highly efficient short hairpin RNA potently down-regulates CCR5 expression in systemic lymphoid organs in the hu-BLT mouse model Blood, 115 (8), 1534-1544 DOI: 10.1182/blood-2009-04-215855
Image Source: Wikimedia Commons