An age-related decline of CD62L and vaccine response: a role of microRNA 92a?

Aging process can affect T cell and antibody response to vaccination and an age-related decline in the expression of CD62L on CD8(+) T-lymphocyte is one of the important factors that contribute. A recent report demonstrated that percentage of CD3(+)CD8(+)CD62L(+) cells and CD8(+) T-lymphocyte microRNA-92a levels significantly decline with the age and were positively correlated. These results suggested that the age-related attrition of human naïve T cells could be connected to a reduced microRNA-92a in T-lymphocytes and downregulation of the microRNA-92a level might indicate exhaustion of naïve T-cells due to alteration of the immunologic condition with aging. Further studies are necessary to evaluate whether targeting microRNA-92a as microRNA mimics could be one of the therapeutic strategies in improving vaccine response in elderly.