Hematopoiesis and Development

In the fetus, committed hematopoietic stem cells develop in the mesoderm and migrate to the fetal liver in the 6th week of pregnancy. Fetal liver stem cells then initiate erythropoiesis and seed the developing thymus (in week 7) and bone marrow (in week 20). In the thymus, alpha beta and gamma delta T cells develop, and the potential also exists for various dendritic cells (DC) and natural killer (NK) cell types. In the bone marrow, B cells, granulocytes, monocytes and DC all potentially develop. This pattern persists well into adulthood.

Related Information

• Mini-review: Cytokine Regulation During Embryonic Hematopoiesis
• Mini-review: Thrombopoietin (Tpo)