title: A validated real-time quantitative PCR approach shows a correlation between tumor burden and successful ex vivo purging in follicular lymphoma patients.
abstract: OBJECTIVE
  Purging procedures are increasingly used to provide stem cell collections devoid of contaminating tumor cells. In follicle center lymphoma (FCL), most approaches eradicate polymerase chain reaction (PCR);-detectable disease in only a fraction of harvests undergoing ex vivo manipulation. In this study we evaluated whether there is a relationship between tumor burden of stem cell harvests and successful clearance of PCR-detectable disease following ex vivo manipulation.
  
  
  METHODS
  To address this issue, we developed a real-time PCR approach for quantitative measurement of tumor contamination using the bcl-2 rearrangement. Real-time PCR was used to evaluate the relationship between tumor burden of stem-cell harvests and purging effectiveness in PCR(+) samples derived from 10 FCL patients. Ex vivo purging was performed using the MaxSep cell separator (Baxter Immunotherapy, Deerfield, IL, USA).
  
  
  RESULTS
  Our real-time PCR method proved effective, sensitive, accurate, and reproducible. Four collections were successfully cleared of minimal residual disease (MRD) whereas six remained PCR(+). Real-time PCR showed that the four collections successfully cleared of MRD had a prepurging tumor burden significantly lower than those remaining PCR(+) (p = 0.04).
  
  
  CONCLUSIONS
  This study provides the first evidence that evaluation of tumor burden in stem-cell harvests by real-time PCR can predict the effectiveness of therapeutic intervention in non-Hodgkin's lymphoma. Based on these findings, we foresee a more widespread use of this technique to evaluate the impact of different therapeutic approaches in FCL.
authors.affiliation: Divisione Universitaria di Ematologia, Azienda Ospedaliera S. Giovanni Battista, Torino, Italy. marco.ladetto@unito.it
authors.forename: M
authors.initials: M
authors.lastname: Ladetto
authors.forename: S
authors.initials: S
authors.lastname: Sametti
authors.forename: J W
authors.initials: JW
authors.lastname: Donovan
authors.forename: D
authors.initials: D
authors.lastname: Ferrero
authors.forename: M
authors.initials: M
authors.lastname: Astolfi
authors.forename: M
authors.initials: M
authors.lastname: Mitterer
authors.forename: I
authors.initials: I
authors.lastname: Ricca
authors.forename: D
authors.initials: D
authors.lastname: Drandi
authors.forename: P
authors.initials: P
authors.lastname: Corradini
authors.forename: P
authors.initials: P
authors.lastname: Coser
authors.forename: A
authors.initials: A
authors.lastname: Pileri
authors.forename: J G
authors.initials: JG
authors.lastname: Gribben
authors.forename: C
authors.initials: C
authors.lastname: Tarella
mesh_terms: D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D001781:Blood Component Removal / Q000379:methods*; D015321:Gene Rearrangement; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D008224:Lymphoma, Follicular / Q000097:blood* / Q000628:therapy; D008875:Middle Aged; D008969:Molecular Sequence Data; D018365:Neoplasm, Residual / Q000097:blood; D016133:Polymerase Chain Reaction / Q000379:methods*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014178:Translocation, Genetic; D014182:Transplantation, Autologous
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases