The aging bone marrow and its impact on immune responses in old age.

With aging the immune system undergoes significant age-related changes. These age-dependent changes are referred to as immunosenescence and are partially responsible for the poor immune response to infections and the low efficacy of vaccination in elderly persons. Immunosenescence is characterized by a decrease in innate and adaptive cell-mediated immune function in the peripheral blood and the bone marrow. The aging of bone marrow cells and in particular, of adaptive immune cells in the bone marrow has been addressed relatively rarely. It is therefore the goal of this review to summarize what is known about the effect of age on bone marrow immune cells and their precursors in mice and humans.