In my practice, rituximab at 375mg/m2 causes hypotension in most patients, about 60% need downward adjustment of their infusion rates and about 25% the hypotension is severe enough to be symptomatic. I would expect the hypotensive reactions to be more severe and frequent at the dose of 500mg/m2 used in the CFS protocol. If the patients signed a proper consent form they would have been warned that hypotension would be a risk, therefore most patients would be aware that they had received rituximab rather than placebo. The physicians who administered the rituximab would have to be adjusting the infusion rate in most patients and would also be aware that they had given the active drug rather than the placebo.Interesting.
Therefore the statement that the study was double blinded is incorrect; it is not possible to double blind rituximab for the above reasons. Furthermore, the results are based on subjective, "how do I feel" criteria which could be influenced by the patients knowledge that they had received rituximab.
(As a side note: It is sad to see that Jamie always brings up XMRV)