title: Kinetics of CFU-Mk after automated plateletpheresis.
abstract: OBJECTIVE
  Platelet count, thrombopoetin (TPO) level and the compartment of megakaryocyte progenitor cells (CFU-Mk) are major determinants in the regulation of thrombopoiesis. The aim of this study was to investigate the potential changes in the compartment of CFU-Mk and their correlation with serum TPO levels and platelet count after plateletpheresis.
  
  
  METHODS
  Twelve healthy individuals were randomly assigned to undergo single-donor plateletpheresis. A collagen-based in vitro culture system was used to determine the number of peripheral blood (PB) CFU-Mk before and after donation and on days 1, 4 and 7 thereafter. TPO levels were measured by a specific enzyme-linked immunosorbent assay and whole blood counts were performed using an automated cell counter.
  
  
  RESULTS
  The pre-apheresis platelet count (mean +/- SEM: 276 +/- 13 x 10(9)/l) decreased after plateletpheresis to a nadir of 194 +/- 8 x 10(9)/l (P < 0.001), showed a gradual increase on days 1 and 4, and reached pre-apheresis values by day 7 (280 +/- 11). The serum TPO levels were found to be significantly increased on days 1 and 7 as compared to baseline levels (baseline value 103.3 +/- 18.5 pg/ml versus day-1 value 135.8 +/- 25.8 pg/ml and day-7 value 132 +/- 30.19 pg/ml; P < 0.03 and P < 0.03, respectively). The numbers of CFU-Mk in PB were significantly elevated on day 4 only (125 +/- 21 colonies/ml of PB versus pre-apheresis values of 68 +/- 18 colonies/ml of PB, P < 0.005).
  
  
  CONCLUSIONS
  These findings suggest that platelet loss during plateletpheresis affects thrombopoiesis at the progenitor cell level, probably through alterations in TPO plasma concentrations.
authors.affiliation: Department of Blood Group Serology & Transfusion Medicine, University of Graz, Graz, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Wagner
authors.forename: D W
authors.initials: DW
authors.lastname: Schwartz
authors.forename: M
authors.initials: M
authors.lastname: Winter
authors.forename: E
authors.initials: E
authors.lastname: Kabrna
authors.forename: M
authors.initials: M
authors.lastname: Kollars
authors.forename: I
authors.initials: I
authors.lastname: Schwarzinger
authors.forename: G
authors.initials: G
authors.lastname: Lanzer
authors.forename: W R
authors.initials: WR
authors.lastname: Mayr
authors.forename: K
authors.initials: K
authors.lastname: Geissler
mesh_terms: D001772:Blood Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D006410:Hematopoiesis; D006801:Humans; D007700:Kinetics; D008533:Megakaryocytes / Q000166:cytology*; D023461:Myeloid Progenitor Cells / Q000166:cytology*; D010976:Platelet Count / Q000295:instrumentation; D010983:Plateletpheresis / Q000295:instrumentation*; D013926:Thrombopoietin / Q000097:blood
chemical_list: D013926:Thrombopoietin