CCR5∆32 -- if you have this mutation on both sides of your family, you are fully immune; if only one side, you are mostly immune. It's not common, but there is a case of a German man who was cured of AIDS after receiving a bone marrow transplant from someone who was heterozygotic for the mutation.

The fifth person cured with a CCR5∆32 bone marrow transplant was announced today. At least it hit my feed today anyway.

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In Sweden it is not that uncommon that people are immune to HIV. I know that i have seen articles talking about 15%, but i don't think any large population wide studies has been made so they are estimates.

The core theory is that the resistance mutation was developed in Sweden and that the Vikings brought the resistance with them to the rest of Europe on their adventures during the Vendel and Viking age. This might explain the high amount of resistant people in Finland, Russia and the Baltic countries today along with Sweden.

The HIV bypasses the human immune system by hiding inside and attacking the T-helper cells. The T-helper cells are responsible for activating the other cells such as the Natural Killer cells to fight and attack against an infection.

It seems like the CCR5 delta 32 mutation disables the CCR5 receptor on the surface of white blood cells/T-helper cells. The HIV uses this CCR5 receptor to latch onto the T-helper cells and get into it.

People with these genes are immune to HIV because the HIV can't latch onto the white blood cells/T-helper cells.

The current traditional vaccines don't work against HIV because vaccines are about making the T-helper cells activate the other cells to fight against the infection. The HIV goes straight to the T-helper cells. Without the T-helper cells, the immune system is compromised and the body is completely helpless against infections.

Things like the bone marrow transplants work because the bone marrow creates the blood cells like the T-helper cells (without the CCR5 receptor).

What's the use of CCR5 receptor? What are the implication (other than being immune to HIV) if a T-Helper cell lacks CCR5 receptors?

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Its exact role in the immune system is unknown and it doesn’t seem absolutely necessary, similar to how people who are heterozygous for sickle cell anemia do not display symptoms because they have sufficient amounts of normal blood cells even if some of their blood cells are sickle cells.

Would that indicate a large population crash in “pre-history” caused by HIV? Leaving only those with the CCR5 mutation to repopulate? That would indicate that HIV has been around for a very long time and have big historical implications.

Not necessarily, as population bottlenecks sometimes concentrate a random mutation in a population.

The gene might also be beneficial in some other way we don't yet understand.

Didn't the double mutation give you immunity to the plague in Europe too? Unfortunately if you survived and your village did not, you were obviously a witch and summarily burned at the stake.

My understanding is that it has negligible side effects other than some good immunities. If you run into a conspiracy type person it's a great rabbit hole to send them down. Mention HIV is probably a conspiracy and an elite group of people are immune to it. =)

There has been some research into the negative side affects of having the mutation. Some include having more negative side affects from the flu and west nile.

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You are not "fully immune", because HIV has two tropisms. CCR5 and CXCR4. CXCR4 tropic HIV can infect a person with CCR5∆32

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But if you were the only person who survived, and your village did not, who would be around to call you a witch, let alone burn you? Other survivors? Then wouldn’t they be witches too? So you’d all have like a secret understanding? Like a special handshake, or wink of an eye?

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Neighbouring villages. It was never 100% simultaneous saturation. But really, you're applying logic to witch hunters? That seems ineffectual.

But the one who survived, could theoretically get out of it by declaring “they were the chosen one” (with the right tone), and then take over the neighboring village.

No real science ever confirmed this theory.

Interesting, those conspiracy theorists would be making the exact same mistake as the witch hunters

Evolution is random. Sometimes outside circumstances guide this randomness, sometimes it doesn't. (or the mutation coincides with another mutation that is more actively selected for)

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I see 4.9% of 555 newly diagnosed HIV infections in France between 2003-10, were the CXCR4-tropic variant. And of these, 1.5% were involved in a transmission clusters (one case).

I think it means the CXCR4-tropic variant usually arises/evolves after infection, it's less often involved in transmission?

I think they hypothesize, if I understand the paper correctly, that the CXCR4-tropic variant is less infectious than CCR5 variants.

Frange, P., Meyer, L., Ghosn, J., Deveau, C., Goujard, C., Duvivier, C., Tubiana, R., Rouzioux, C., Chaix, M.L. and ANRS CO6 PRIMO Cohort Study Group, 2013. Prevalence of CXCR 4‐tropic viruses in clustered transmission chains at the time of primary HIV‐1 infection. Clinical Microbiology and Infection, 19(5), pp.E252-E255.

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Other viruses could interact with CCR5

Smallpox is the primary candidate as its relatives interact with the same receptor family, and this study shows a protective effect against HIV from smallpox vaccination suggesting antigens between the two viruses are somewhat similar in an example of convergent evolution

It’s much less random than people believe

the mutations are mostly always happening, they usually only become widespread enough to notice when a change in environment selects for it so it can spread.

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I can’t find any evidence that anybody was ever burnt at the stake for surviving plague. Where did you get that? It did not have a 100% kill rate either…

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Yup. Kinda. If you have two copies of the ccr5 delta 32 you can come into contact with hiv but it can’t get past the ccl5 and GP120 due to the mutation. Less protection with 1 copy. There’s still research on any negative impacts this mutation might cause.

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Generally speaking, yes it's quite possible that some people are immune to HIV, the trouble is that because they never get infected, people don't really know they contracted it, and then fought it off.

Transmission rates are also not 100%, especially if you're a 'top' the chances of not getting it go down even further, so it's very hard to test against a control. Were somebody to become aware of a possible infection the standard operating procedure would be to start an anti viral regiment as soon as possible to prevent the infection from taking hold, which further reduces the chances to study this possibility.

There have been tidbits of useful data though, such as the Berlin patient which has been mentioned by others.

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Ooooh let’s do this gene trick with rabies now, then I’ll be able to sleep better.

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