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Discussion Starter · #1 ·
Just want to confirm something..
is the mutation of CRCX4 will give you a FULMINANT HIV Course? i suppose cause directly will get to Th4 and no macrophage, CTL or NK help from them...? please enlighten me! a friend of mine got this question about mutation on CRCX4 :confused:
 

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Just want to confirm something..
is the mutation of CRCX4 will give you a FULMINANT HIV Course? i suppose cause directly will get to Th4 and no macrophage, CTL or NK help from them...? please enlighten me! a friend of mine got this question about mutation on CRCX4 :confused:
It seems that HIV can't identify a mutated CXCR4 receptor on CD4+ helper T cell which helps T cells evade fusion & entry of HIV & is protective. Heterozygous mutation will slow the progression of HIV & homozygous mutation is for lucky people (immunity) :)

FA mentions this for CCR5 mutation. This may be the same for CXCR4 as well, but I'm not sure.
 

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Think of it this way, in the world of USMLE there is only 1 strain of HIV (in real life there are multiple that work in different ways, but for USMLE there is only 1 :p ). This strain of HIV initiates infection through the CCR5 receptor and then causes massive damage through the CXCR4. CCR5 is predominantly expressed on Macrophages (and T-Cells too, but macrophages is the big one to remember) and CXCR4 is expressed on CD4+ T-Cells.

So in the initial stages, macrophages will be infected and as the disease progresses, HIV will affect T-Cells, leading to the severe immunodeficiency we call AIDS.

Using this very simplified (and not 100% accurate) framework, it stands to reason that if you have a homozygous mutation of CCR5, HIV can never initiate the infection and thus you are immune. If you are heterozygous, you can still get the infection but the course will be less severe and take a lot longer for you to go to full blown AIDS.

As for CXCR4 mutations I havent met any person yet who has been tested on CXCR4 mutations, but such a mutation would potentially lead to another form of immunodeficiency that my teacher mentioned in passing once named WHIM Syndrome which I dont fully understand the pathogenesis of so I cant really help you out with. In short, dont worry about CXCR4 mutations as they are not related to HIV, lead to a disease that I havent seen in FA, and I have never met anyone who has been tested on it. If im mistaken, then please someone do correct :p
 

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Discussion Starter · #6 ·
Thank u so much admin!! Very interesting and This is such high yield cause hiv is all over step1. Thank you!!
 
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