I just searched Hacker News for earlier stories about treatments for the same syndrome, and see that about a half year ago here a very preliminary study was the topic of a busy thread. The article submitted just now is a good follow-up on what clinical trial data are still needed to see whether or not rituximab is a safe and effective treatment (my guess is NOT) for chronic fatigue syndrome/systemic exertion intolerance disease.[1]

[1] https://www.sciencebasedmedicine.org/iom-recommends-replacin...