Interleukin-7 and Immunosenescence

Figure 5

While thymic regeneration of T cells in healthy adults experiences a 10–100-fold decrease, homeostatic T cell proliferation remains stable throughout life. Both T cell lineages decrease by 2–5-fold in diversity. However, differences in the homeostatic proliferation of CD4+ and CD8+ cells drive the imbalance of these cells observed in aging: there is a modest increase in the clonality of CD4+ cells but a large increase for CD8+ cells with a concomitant decline in the size of the CD8+ compartment.