I just posted abstracts for these two papers on the "Other Health News and Research" section of the forums: Endothelial histamine H1 receptor signaling reduces blood-brain barrier permeability... Inflammatory mediators and modulation of blood-brain barrier permeability Blockade of histamine H2 receptors attenuate blood-brain barrier permeability, cerebral blood flow.. Together, these papers suggest and important role for histamine in the modulation of blood-brain barrier permeability and how increased permeability leads to encephalomyelitis. It is no secret that I am fairly convinced that ME/CFS is simply undiagnosed Mast Cell Activation Disorder. As histamine is one of the mediators released by mast cells, blockade of the appropriate histamine receptors should help deal with the encephalomyelitis part of ME/CFS. These papers, taken together, suggest that blockade of the H2 receptor may help prevent/attenuate encephalomyelitis.