My current model of PASC is that the spike protein creates zombie monocytes: https://www.biorxiv.org/content/10.1101/2021.06.25.449905v1.full

Persistent elevated monocytes on a standard blood assay with no other explanation (any kind of infection) are a possible indication.

Also, while the original article has been taken down, smokers are at higher risk of acute CV symptoms (unsurprising), but significantly lower risk of PASC - and nicotine seems to promote apoptosis of the zombie monocytes.  (But what dose is required?)