The only clinical trial targeting antibodies found moderate to marked clinical improvements in 10 of 15 subjects treated with rituximab, a B cell depleting antibody, and 2 of 15 placebo arm subjects at a single time point (Fluge et al., 2011). This, however, was a post hoc analysis as the trial failed to meet its primary endpoint. Currently, researchers in the United Kingdom and Norway are conducting further studies addressing this question (Edwards, 2013; Mella and Fluge, 2014).
Edwards, J. 2013. UK rituximab trial—statements by professor Jonathan Edwards and invest in ME.
http://www.ukrituximabtrial.org/Rituximab news-July13 01.htm (accessed May 14, 2014).
Fluge, O., O. Bruland, K. Risa, A. Storstein, E. K. Kristoffersen, D. Sapkota, H. Naess, O. Dahl, H. Nyland, and O. Mella. 2011. Benefit from B-lymphocyte depletion using the anti-CD20 antibody rituximab in chronic fatigue syndrome. A double-blind and placebocontrolled study. PLoS ONE 6(10):e26358.
Mella, O., and O. Fluge. 2014. B-lymphocyte depletion using rituximab in chronic fatigue syndrome/myalgic encephalopathy (CFS/ME). A randomized phase-III study. (RituxME).
https://clinicaltrials.gov/ct2/show/NCT02229942 (accessed September 17, 2014).