https://www.jax.org/news-and-insigh...s-federal-grant-for-chronic-fatigue-research#
this announcement of funding from last year was retweeted in response to his tweet
includes this paragraph
Unutmaz proposes to undertake a major study of ME/CFS patients, screening blood samples for potential immunological biomarkers of the disease, and using the results to develop better diagnostic tools and personalized treatments for the disease.
This assumes that the marker is to be found in the blood. To me this sounds like looking under the lamppost: perhaps we have a dysfunction that happens inside of cells, is disseminated in fluids other than the blood, is an interaction between cells and mitochondria, etc.
I don't know enough biology to name all the bodily processes, but I do know that there's a bit more in your body than blood. It just happens that it's very easy to take a bit of blood out and send it to a lab.
Sort of like analyzing the engine oil in the car; you can tell a great deal about what's going on by sending a little used oil out for analysis, but that's not going to find an occluded oil passage which will only become a problem at very low temperatures. Then not enough oil will flow and the engine will seize up, leaving you to freeze to death somewhere in the arctic tundra.
To find the problem you'll either have to chill the whole thing, hook up instruments and carefully measure oil pressure and flow under many different conditions, or disassemble the engine and find the partly blocked passage. Drawing off a little oil and sending it to a lab is rather easy. The engine exam expedition for a hidden defect is not.