CD44 and Cognitive impairment: CD8+ T-cells can differentiate into distinct subpopulations based on the functions, and the expression of cell surface receptor molecular CD44 and CD62L.21,22 Recent studies have shown that the recruitment of clonal CD8+ T effector memory cells into the brain is linked to cognitive impairment, including aging and AD.23,24 We further explored the subset distribution of peripheral T cells and cytokine levels after HBV treatment.