IL4 and myalgic encephalomeyelitis/chronic fatigue syndrome: In this study, after KXS treatment, splenocyte proliferation and secretion of IL-4 of splenocytes of mice significantly increased, and the abnormal excretion of IL-2 led by CFS decreased, which suggested that CFS may not only affect the balance of the immune system but also improve it in CFS mice through immunomodulation.