Severe CFS/ME patients were significantly reduced in CD56brightCD16dim NKG2D, CD56dimCD16− KIR2DL2/DL3, CD94−CD11a− γδ1T cells and CD62L+CD11a− γδ1T cells at 6 months. The gene discussed is KLRK1; the disease is myalgic encephalomeyelitis/chronic fatigue syndrome.