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Posted On: 06/22/2022 10:18:46 AM
Post# of 148885
Quote:
The multiple and overlapping feedback loops are what maintains homeostasis across multiple biological systems.
The entire point of targeting CCR5 in disease is that the increase in CCR5 is disrupting homeostasis. I am well aware of the feedback loops that exist with CCR5 which are based on the ligand activation. Let's take a look at CCL5 (RANTES), It also binds to CCR3 and CCR4. The
highest binding affinity is by far CCR5. CCR3 and CCR4 expression is a small fraction of CCR5 expression. In an over-reactive immune system you will see an increase in all CCR receptors but CCR3 and CCR4 are still a small increase compared to CCR5.
There is a feedback loop where CCL5 increases CCR5 expression and that increased expression further elevates CCL5 levels. Blockade of CCR5 breaks that loop at 700mg as can be seen in Patterson's paper - "CCR5 inhibition in critical COVID-19 patients decreases inflammatory cytokines, increases CD8 T-cells, and decreases SARS-CoV2 RNA in plasma by day 14".
Yet you see a dramatic increase in CCL5 levels at 700mg in the NASH poster.
As can be seen in a myriad of papers the increase in CCR5 receptor occupancy by any drug mirrors a decrease in chemokines.
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