IL4 and myalgic encephalomeyelitis/chronic fatigue syndrome: Bedoui, et al. (2003) [14] demonstrated that NPY, a neuropeptide found at elevated levels in female CFS patients [15] (n = 93 females; age 44 ± 0.9 years [18–60 years]), suppressed IFNγ production in Th-1 cells and increased production of IL-4 by Th2 cells.