On the other hand, the serum levels of CD3+CD8+ EVs were significantly higher in patients with EBV infection, lower in RA patients, and not different in AD and OA patients relative to the control (Figure 7(c)), according to clinical findings of increased and decreased CD8+ T cell counts in EBV infection and RA, respectively [51, 55, 56]. Here, CD8A is linked to Epstein-Barr virus infection.