Identification of B/macrophage progenitors in adult bone marrow.
Current models of adult hematopoiesis propose that pluripotent hematopoietic stem cells (PHSC) differentiate into common myeloid- and lymphoid-committed precursors and that this establishes an early separation between the myeloid and lymphoid lineages. However, the description of rare, and previously unidentified, B/macrophage progenitors in postnatal bone marrow is not consistent with this model. Hypotheses to explain and reconcile their existence are discussed with particular emphasis on the possibility that fetal B/macrophage progenitors, whose development is well accepted, may persist into adult life. The existence of a normally occurring adult B/macrophage progenitor has implications for understanding the origin of tumors with B cell and myeloid characteristics.
Montecino-Rodriguez
Encarnacion
E
Department of Pathology and Laboratory Medicine 173216, UCLA School of Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095-1732, USA.
Dorshkind
Kenneth
K
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D001853:Bone Marrow / Q000502:physiology; D019070:Cell Lineage / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000502:physiology; D006801:Humans; D007107:Immune System / Q000196:embryology / Q000502:physiology; D038041:Lymphopoiesis / Q000502:physiology*; D008264:Macrophages / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology*