Figures & data
FIGURE 1. Summary of Age-Related Changes in the Immune System. Steady-state turnover of the immune system begins in the bone marrow with haematopoietic stem cells (HSCs), which give rise to both myeloid and lymphoid lineages. Along the lymphoid lineage, T-cells mature in the thymus and become positive for CD4 or CD8. Monocytes, derived from myeloid progenitor cells, travel through the blood steam to sites of recruitment and enter tissues as elicited macrophages. HSCs, T-cells, and macrophages all experience cellular changes with aging.
