This paper seems to have been missed (I coudn't find it here, apologies if this is a repost). Perhaps that's because this paper is a conference paper that reports negative results. Negative results are still informative, in this case very much so if you are interested in the topic of gut permiability... Assessment of intestinal tight junction proteins in Chronic Fatigue Syndrome Rachel J. Passmore, E. W. Brenu, S.B. Ramos, S. Marshall-Gradisnik, N. Wong, S.L. Hardcastle, S. Johnston, A. Hawthorn, T.Nguyen, T.K Huth National Centre for Neuroimmunology and Emerging Diseases, Griffith Health Institute, Griffith University, Parklands, Queensland, Australia. ResearchGate link (PDF of full paper is available for download) "The aim of this study was to determine whether the gastrointestinal symptoms in CFS are caused by increased permeability in tight junctions resulting in subsequent translocation of pathogenic bacteria into the lumen. Serum concentrations of the intestinal proteins zonulin, LPS, and FABP2 were examined in CFS patients and healthy controls." "As increased tight junction permeability has been implicated in the pathogenesis of other fatigue associated diseases, where the translocation of pathogenic bacteria out of the intestinal mucosal layer causes an inflammatory response [5,8,9], it is reasonable to conclude that it may also be implicated in the aetiology of CFS. However, as these were no significant differences in the concentrations of any of the tight junction proteins measured, this suggests that increased permeability and subsequent translocation of bacteria into the lumen may not contribute to the pathogenesis of gastrointestinal symptoms in CFS. In addition, further classification of CFS patients based on gastrointestinal symptomatic criteria may be beneficial to further understanding the role of the tight junctions in CFS."