I am not sure I agree about that. IL-1 might well be acting locally, with nothing to find in the blood. Doing blood levels would be sensible and I expect they will do them, but they certainly should not be the primary outcome measure. If you think about it showing that an IL-1 inhibitor inhibits IL-1 in PWME tells you nothing whatsoever about ME - just that you put the right drug in the bottle. The end point is designed to show that in PWME the inhibitor benefits symptoms - i.e. fatigue, so fatigue is precisely the right endpoint!
I am sorry but it sounds more like speculation rather than science. It is also inconsistent with the findings of Lipkin. If they use patiënts who are longer sick then 3 years beacause only in the first three years cytokines are elevated.