CD2 and myalgic encephalomeyelitis/chronic fatigue syndrome: CD56dimCD16− NK cell CD2 expression was significantly lower in moderate CFS/ME compared with severe CFS/ME patients (p = 0.033) while CD18+CD2− was increased in moderate CFS/ME patients compared with controls and severe CFS/ME in CD56dimCD16− NK cells (p = 0.009 and 0.035 respectively).