CD81 and myalgic encephalomeyelitis/chronic fatigue syndrome: Despite the fact that EVs isolated with TEIR reagent include vesicles with exosomal morphology and size-range under transmission electronic microscopy (Fig. 3A), and the presence of the exosomal markers CD9 and CD81 were evidenced by western blotting (Fig. 3B), our procedures were limited at estimating the relative abundance of exosomes and other vesicle subgroups in general, and therefore any potential attribute of exosomes or other vesicle subtype in ME/CFS would be merely speculative.