TNF and myalgic encephalomeyelitis/chronic fatigue syndrome: No difference in the risk AF of the TNF rs1800629 SNP between patients and controls was observed, but the AF of the TNF rs1799724 risk allele T again was significantly lower in ME/CFS patients without ITO (AF 8%, OR 0.55, p = 0.043), compared to healthy controls (AF 13%, Table 3).