CSF2 and myalgic encephalomeyelitis/chronic fatigue syndrome: There was no difference between the treatment and control groups on day 0 (IgG control: 3.1 ± 0.5, anti–GM-CSF: 3.1 ± 1.0, P > 0.05); however, mice treated with anti–GM-CSF had significantly lower CFS scores compared to the control group on both days 3 (IgG: 11.2 ± 1.2, anti–GM-CSF: 5.4 ± 1.2, P = 0.001) and 7 (IgG: 10.9 ± 0.7, anti–GM-CSF: 6.2 ± 0.9, P < 0.001, Fig. 5B).