TNF and myalgic encephalomeyelitis/chronic fatigue syndrome: Associations between the occurrence of ME/CFS clinical symptoms, HHV−6, HHV−7 and B19 infection/co-infection reactivation, and increased expression levels of TNF-α and IL6 [40] have been observed, as well as alterations in the levels of infection markers of B19V [41] and EBV [42].