Hematopoiesis is a hierarchically organized process in which a population of hematopoietic stem cells (HSCs) gives rise to all blood cell lineages. HSCs possess the ability to differentiate into all functionalblood cells and self–renew. Through a series of lineage commitment steps, HSCs give rise to progeny that progressively lose self-renewal potential causing them to become more restricted in their differentiation capacity, generating multi-potential and lineage-committed progenitor cells, and ultimately mature functional circulating blood cells.

The capability of hematopoietic stem cells to self-renew and differentiate is fundamental for the formation and maintenance of life-long hematopoiesis.Hematopoietic stem cells are highly valuable for their ability to reconstitute the hematopoietic system when transplanted. This has enabled their use in the clinic to treat a variety of disorders including bone marrow failure, myeloproliferative disorders and other acquired or genetic disorders that affect blood cells.