CD28 and myalgic encephalomeyelitis/chronic fatigue syndrome: However, modest differences were observed in several differentiation populations in the CD8+ T cell compartment (Figure 5B) with a small increase in the proportion of EM cells (CCR7-CD45RA-CD28-CD57-) and a reduction in the proportion of terminally differentiated cytotoxic effector TEMRA cells (CCR7-CD45RA+CD28–CD57+) in people living with ME/CFS.