title: Increased apoptosis in cryopreserved autologous hematopoietic progenitor cells collected by apheresis and delayed neutrophil recovery after transplantation: a nested case-control study.
abstract: OBJECTIVE
  Delayed neutrophil recovery following autologous hematopoietic stem cell transplantation (aHSCT) increases transplant-related morbidity. Apoptosis induced by cryopreservation and thawing of hematopoietic progenitor cells collected by apheresis (HPC-A) was investigated in this nested case-control study as a factor associated with delayed neutrophil recovery following aHSCT.
  
  
  METHODS
  Among patients with lymphoma who underwent aHSCT between 2000 and 2007 (n = 326), 13 cases of primary delayed neutrophil recovery and 22 age- and sex-matched controls were identified. Apoptosis and viability were measured using multiparameter flow cytometry, and colony-forming capacity was determined using semi-solid methylcellulose assays.
  
  
  RESULTS
  HPC-A grafts from cases and controls had similar percentages of viable mononuclear cells (MNC) and CD34+ progenitor cells, as determined by standard 7AAD dye exclusion methods measured before and after cryopreservation. Patients with delayed neutrophil recovery received increased numbers of apoptotic MNC (P = 0.02) but similar numbers of apoptotic CD34+ cells per kilogram measured after thawing. Apoptosis was more pronounced in MNC compared with CD34+ cells after thawing, and apoptosis was negligible in freshly collected HPC-A products. Patients with delayed neutrophil recovery had fewer total colony-forming unites (CFU) and CFU-granulocyte-macrophages (GM) per 10(5) viable post-thaw MNC compared with controls (P < 0.05).
  
  
  CONCLUSIONS
  Increased numbers of apoptotic MNC in thawed HPC-A products are associated with delayed neutrophil recovery after aHSCT. Studies that address factors contributing to increased apoptosis are needed, and measuring apoptosis in thawed HPC-A may have a role in the assessment of graft adequacy.
authors.affiliation: Regenerative Medicine Program, Ottawa Hospital Research Program, Ottawa, Canada.
authors.forename: Luke
authors.initials: L
authors.lastname: Wu
authors.forename: Ayman
authors.initials: A
authors.lastname: Al-Hejazi
authors.forename: Lionel
authors.initials: L
authors.lastname: Filion
authors.forename: Robert
authors.initials: R
authors.lastname: Ben
authors.forename: Michael
authors.initials: M
authors.lastname: Halpenny
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Antonio
authors.initials: A
authors.lastname: Giulivi
authors.forename: David S
authors.initials: DS
authors.lastname: Allan
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology; D017209:Apoptosis / Q000276:immunology*; D001781:Blood Component Removal / Q000379:methods; D016022:Case-Control Studies; D002470:Cell Survival / Q000276:immunology; D015925:Cryopreservation; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008223:Lymphoma / Q000628:therapy; D009504:Neutrophils / Q000276:immunology* / Q000473:pathology*; D013234:Stem Cells; D014182:Transplantation, Autologous / Q000009:adverse effects
chemical_list: D018952:Antigens, CD34