CXCL8 and myalgic encephalomeyelitis/chronic fatigue syndrome: As IL-1α, IL-6 and IL-8 were selected from a candidate set of cytokines that were reasonably invariant across age and BMI in healthy subjects this result suggests that duration of illness may be a main factor driving the need for parameter tuning across ME/CFS subgroups, at least in the group of cytokines measured here.