All three criteria were used for each paper? What were the three criteria? The reason this is relevant is because they look like a mixed bag at best, meaning the usual problems with findings, or lack of such.
"Sixteen patients who fulfilled the Centers for Disease Control, British, and/or Australian criteria for chronic fatigue syndrome..."
It also made clear that the definition of abnormality they used was somewhat arbitrary and another paper had used a different definition.
Also the locations for the abnormalities in the second paper were similar to the depression cohort.
These were authors who did say the abnormalities suggested a biological process.
Anyway, I'll need to see more evidence to see how good they are in M.E. specifically. For example, I had relatively mild M.E. for the first few years - would it have shown up I wonder.