IL21 and myalgic encephalomeyelitis/chronic fatigue syndrome: Amongst these significant correlations, levels of LIF in EVs correlated with 8 plasma cytokines in ME/CFS (CCL3, IL15, LIF, IL17, IL21, IFNβ, TGFα and TGFβ) and 5 in the control group (CCL3, IL1α, IL17, IL21 and IFNβ) (Supplemental Fig. 2).