title: Transplantation hematopoiesis.
abstract: Hematopoietic reconstitution after transplantation relies on a small number of hematopoietic stem cells that selectively migrate from the bloodstream to the hematopoietic microenvironment. In the first phase of engraftment, an extreme proliferative demand causes a limited stem cell fraction and its progeny to divide continuously, showing a significant telomere shortening. When all hematopoietic compartments are fully reconstituted, progenitor cell replication stabilizes and the stem cell pool reverts to a quiescent state. In transplant recipients, the hematopoietic microenvironment and stem cell reservoir remain defective for a prolonged period. However, in most patients donor-derived polyclonal hemopoiesis results, and the system is not exhausted but is capable of sustained normal counts and eventually overcomes stressed conditions.
authors.affiliation: Dipartimento di Emato-Oncologia, Ospedale San Martino, Genova, Italy. marinapodesta@smartino.ge.it
authors.forename: M
authors.initials: M
authors.lastname: Podestà
mesh_terms: D000818:Animals; D002633:Chemotaxis; D006085:Graft Survival; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000502:physiology; D006801:Humans; D016615:Telomere / Q000378:metabolism