CD69 and myalgic encephalomeyelitis/chronic fatigue syndrome: In this case, several markers showed consistent alterations in CFS individuals and illustrate a skewed NK cell population with high CD69 and low CD25 expression, a paradoxical phenotype that has been described in acute influenza infection or vaccination[54] and that is in clear conflict with recent data reporting low CD69 expression in NK and T cells from CFS affected individuals[22,23].