Haematopoietic stem cells (HSCs) reside in the medulla of the bone (bone marrow) and have the unique ability to give rise to all of the different mature blood cell types and tissues.[2][3] HSCs are self-renewing cells: when they differentiate, at least some of their daughter cells remain as HSCs, so the pool of stem cells is not depleted. This phenomenon is called asymmetric division.[4] The other daughters of HSCs (myeloid andlymphoid progenitor cells) can follow any of the other differentiation pathways that lead to the production of one or more specific types of blood cell, but cannot renew themselves. The pool of progenitors isheterogeneous and can be divided into two groups; long-term self-renewing HSC and only transiently self-renewing HSC, also called short-terms.[5] This is one of the main vital processes in the body.
In developing embryos, blood formation occurs in aggregates of blood cells in the yolk sac, calledblood islands. As development progresses, blood formation occurs in thespleen,liver andlymph nodes. Whenbone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism.[3] However, maturation, activation, and some proliferation of lymphoid cells occurs in the spleen,thymus, and lymph nodes. In children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.[6]
Haematopoiesis (fromGreek αἷμα, "blood" and ποιεῖν "to make"; also hematopoiesis inAmerican English; sometimes also haemopoiesis or hemopoiesis) is the formation ofblood cellular components. All cellular blood components are derived fromhaematopoietic stem cells.[3] In a healthy adult person, approximately 1011–1012 new blood cells are produced daily in order to maintain steady state levels in the peripheral circulation.[7][8]
All blood cells are divided into three lineages.[9]
Red blood cells, also called erythrocytes, are the oxygen-carryingcells.Erythrocytes are functional and are released into the blood. The number of reticulocytes, immature red blood cells, gives an estimate of the rate oferythropoiesis.
Haematopoietic stem cell transplantation (HSCT) is the transplantation ofmultipotent haematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood.[10][11][12] It may beautologous (the patient's own stem cells are used),allogeneic (the stem cells come from a donor) or syngeneic (from an identical twin).[10][11]
^Monga I, Kaur K, Dhanda S (March 2022). "Revisiting hematopoiesis: applications of the bulk and single-cell transcriptomics dissecting transcriptional heterogeneity in hematopoietic stem cells".Briefings in Functional Genomics.21 (3):159–176.doi:10.1093/bfgp/elac002.PMID35265979.
^Morrison, SJ; Weissman, IL (Nov 1994). "The long-term repopulating subset of hematopoietic stem cells is deterministic and isolable by phenotype".Immunity.1 (8):661–73.doi:10.1016/1074-7613(94)90037-x.PMID7541305.
^Fernández, KS; de Alarcón, PA (Dec 2013). "Development of the hematopoietic system and disorders of hematopoiesis that present during infancy and early childhood".Pediatric Clinics of North America.60 (6):1273–89.doi:10.1016/j.pcl.2013.08.002.PMID24237971.
^Semester 4 medical lectures at Uppsala University 2008 by Leif Jansson
^Tyndall A, Fassas A, Passweg J, et al. (1999). "Autologous haematopoietic stem cell transplants for autoimmune disease–feasibility and transplant-related mortality. Autoimmune Disease and Lymphoma Working Parties of the European Group for Blood and Marrow Transplantation, the European League Against Rheumatism and the International Stem Cell Project for Autoimmune Disease".Bone Marrow Transplant.24 (7):729–34.doi:10.1038/sj.bmt.1701987.PMID10516675.
^Hashemi Taheri AP, Radmard AR, Kooraki S, Behfar M, Pak N, Hamidieh AA, Ghavamzadeh A (September 2015). "Radiologic resolution of malignant infantile osteopetrosis skeletal changes following hematopoietic stem cell transplantation".Pediatric Blood & Cancer.62 (9):1645–49.doi:10.1002/pbc.25524.PMID25820806.S2CID11287381.
^Langereis EJ, den Os MM, Breen C, Jones SA, Knaven OC, Mercer J, Miller WP, Kelly PM, Kennedy J, Ketterl TG, O'Meara A, Orchard PJ, Lund TC, van Rijn RR, Sakkers RJ, White KK, Wijburg FA (March 2016). "Progression of Hip Dysplasia in Mucopolysaccharidosis Type I Hurler After Successful Hematopoietic Stem Cell Transplantation".The Journal of Bone and Joint Surgery.98 (5):386–95.doi:10.2106/JBJS.O.00601.PMID26935461.
