Hemopoietic stem cell (HSC, PPSC) Common myeloid progenitor (CMP, CFU-GEMM) Granulocyte/ monocyte progenitor (GMP, CFU-GM) Pro-dendritic cella (pro-DC) Dendritic cell Neutrophil progenitor (NoP, CFU-G) Neutrophil Basophil/mast cell progenitorb (BMCP) Mast cell progenitor (MCP) Mast cellBasophil progenitor (BaP, CFU-Ba) Basophil Eosinophil cell progenitor (EoP, CFU-Eo) Eosinophil Neutrophil Eosinophil Monocyte progenitor (MoP, CFU-M) Monocyte Macrophage Megakaryocyte progenitorc (MKP, CFU-Meg) Megakaryocyte/ erythrocyte progenitor (MEP) Megakaryocyte Megakaryoblast Platelets Erythrocyte progenitor (ErP, CFU-E) Proerythroblast Orthochromatophilic erythroblast Erythrocyte
FIGURE 10.16 • Hemopoiesis. This chart is based on the most recent concepts in hemopoiesis. It shows blood cells’ development from hemopoietic stem cells in the bone marrow to mature cells and their distribution in the blood and connective tissue compartments. In all lineages, extensive proliferation occurs during differentiation. Cytokines (including hemopoietic growth factors) may and do act individually and severally at any point in the process from the first stem cell to the mature blood or connective tissue cell.
aProdendritic cells are possible to differentiate from common lymphoid progenitor. bIf committed to enter the mast cell lineage, the basophil/mast cell progenitor cell migrates to the spleen where it differentiates into a mast cell progenitor cell. After further differentiation in the spleen, it migrates to the intestine to become a mast cell precursor. cA megakariocyte progenitor cell may also differentiate directly from a common myeloid progenitor cell.
FIGURE 10.17 • Hepatic stage of hemopoiesis. Photomicro -graph of the fetal liver stained with H&E shows active hemopoiesis. The small round bodies (arrows) are mostly nuclei of developing erythrocytes. Although it is difficult to discern, these cells are located between developing liver cells and the wall of the vascular sinus. 350.
of stem cells is self-sustaining). Recent studies indicate that HSCs also have the potential to differentiate into multiple non–blood cell lineages and contribute to the cellular regeneration of various tissues and multiple organs. During embryonic development, HSCs are present in the circulation and undergo tissue-specific differentiation in different organs. Human HSCs have been isolated from umbilical cord blood, fetal liver, and fetal and adult bone marrow. In the adult, HSCs have the potential to repair tissues under pathologic conditions (e.g., is-chemic injury, organ failure). Human HSCs express specific molecular marker proteins such as CD34 and CD90 and at the same time do not express lineage-specific markers (Lin–) that are found on lymphocytes, granulocytes, monocytes, megakaryocytes, and erythroid cells. It is now believed that human HSC can be identified by the Lin , CD34, CD90 , and CD38 cellsurface markers. HSCs are not identifiable in the routine preparation; however, they can be identified and isolated using immunocytochemical methods.
A hemopoietic stem cell (HSC) in the bone marrow gives rise to multiple colonies of progenitor stem cells.
In the bone marrow, descendants of the HSC differentiate into two major colonies of multipotential progenitor cells: The common myeloid progenitor (CMP) cells and the common lymphoid progenitor (CLP) cells.