title: Efficient ex vivo expansion of NOD/SCID-repopulating cells with lympho-myeloid potential in hematopoietic grafts of children with solid tumors.
abstract: BACKGROUND
  The ex vivo expansion of hematopoietic grafts could be an important therapeutic tool for accelerating hematopoietic recovery after administration of high-dose chemotherapy regimens. The fate of the long-term repopulating cells during the ex vivo manipulation of grafts is a critical issue and will ultimately define the clinical applicability of this technology to hematopoietic transplantation.
  
  
  METHODS
  To study the effects of a clinically applicable ex vivo expansion protocol in the proliferative potential of the most primitive human hematopoietic cells, both LTC-IC and NOD/SCID-RC assays were used to determine LTC-IC and NOD/SCID-RC contents of hematopoietic grafts, both before and after expansion (SCF, IL-3, PEG-MGDF Flt3-L and 5% AB serum), in four children with non-hematological malignancies.
  
  
  RESULTS
  The mean percentage of CD34+ cells after expansion was 16%. The numbers of nucleated cells increased 20-fold with a mean three-fold increase in the numbers of CD34+ cells during the expansion period. The CFC content of the samples showed a mean 11-fold increase (range: 5-17) after ex vivo expansion. The primitive hematopoietic stem cell content of the expanded cell fraction evaluated by LTC-IC assays was found to be increased in two patients out of three, with maintenance of the LTC-IC frequency in the third patient. The NOD/SCID-RC potential, evaluated in five experiments from four patients using 109 mice injected 5-6 weeks earlier with human hematopoietic cells, increased from a mean percentage of 36% (range: 7-75%) before expansion, to a mean percentage of 70% (range: 37-100%) after expansion (P < 0.00001). The frequency of NOD/SCID-RC calculated with pooled data from all patients was 1/80,000 at day 0 and 1/40,000 after seven days of culture. The full phenotypic analysis of human hematopoietic cells obtained in NOD/SCID mice injected with expanded cells showed the presence of significant numbers of CD34+, CD19+ and CD15+ cells, suggesting the persistent lympho-myeloid potential of the expanded hematopoietic cells.
  
  
  CONCLUSIONS
  Our results suggest that efficient expansion of NOD/SCID-RC with lympho-myeloid potential can be achieved not only in cord blood or normal marrow as previously reported, but also in hematopoietic grafts obtained from children exposed to high-dose chemotherapy.
authors: Departamento Basico de Medicina, Hospital de Clinicas, Montevideo, Uruguay.
authors: C
authors: C
authors: Tourino
authors: F
authors: F
authors: Pflumio
authors: S
authors: S
authors: Novault
authors: A
authors: A
authors: Massé
authors: M
authors: M
authors: Guiller
authors: M L
authors: ML
authors: Bonnet
authors: D
authors: D
authors: Valteau-Couanet
authors: O
authors: O
authors: Hartmann
authors: W
authors: W
authors: Vainchenker
authors: F
authors: F
authors: Beaujean
authors: L
authors: L
authors: Coulombel
authors: A G
authors: AG
authors: Turhan
mesh_terms: D000818:Animals; D002675:Child, Preschool; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007223:Infant; D038041:Lymphopoiesis; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D038042:Myelopoiesis; D009369:Neoplasms / Q000188:drug therapy / Q000503:physiopathology*