For example, the predominant TRM cells associated with the pathogenesis of AIH are CD8+CD69+CD103+ TRM cells that highly express PD1, CXCR3 and granzyme B (36); whereas liver TRM cells of patients with acute hepatitis A are mainly CD8+CD69+CD103- TRM cells that express high levels of HIF-2α (55). Here, CD8A is linked to hepatitis A virus infection.