CD4 and myalgic encephalomeyelitis/chronic fatigue syndrome: Accordingly, IL-10 released by both EBV-transformed B cells and Tregs would favor a Th2 type immune response (43), and gp42-mediated disruption of TCR-MHC-II interaction would further decrease CD4 T cell activation, leading to poor CD4 T cell immunity to mitogens and other specific antigens, which have been described in some patients with ME/CFS (2).