title: Positive and negative selection to reduce tumour contamination in peripheral blood stem cell harvests.
abstract: Peripheral blood progenitor cells used during high dose treatments for malignancy may be contaminated with tumour cells that could later contribute to recurrence. CD34+ selected harvests still contain tumour cells and an additional negative selection may be capable of reducing this contamination. We have assessed a two-stage technique in which a CD34+ selection is followed by a tumour specific depletion stage using a B cell or breast cancer specific antibody panel. Initial small-scale selections on 11 patients with NHL and breast cancer showed that cell loss was greatest following the CD34+ selection with a median yield of 38.8 per cent (range 17. 2-56.4 per cent). The addition of the depletion stage resulted in a minimal loss of CD34+ cells with a yield for this step of 94.2 per cent (range 77.5-99.3 per cent). Clinical scale selections were performed on seven patients with CLL and a median of 2.8x10(6)/kg CD34+ cells (range 1.5-6.1x10(6)/kg) were collected. Cell recovery was 53.3 per cent following CD34+ selection and 76.9 per cent following the tumour specific depletion stage, resulting in a final product containing a median of 1.0x10(6)/kg CD34+ cells (range 0. 55-2.0x10(6)/kg). All unmanipulated harvests were heavily contaminated with tumour cells (median contamination 10.2 per cent, range 2.0-83.1 per cent) as measured by flow cytometry and a median 4.7 log (range 3-5 log) tumour cell purge was produced following two-stage selection. Six of the patients have received cells manipulated in this way with median engraftment times of neutrophils>0.5x10(9)/l=16 days (range 13-20 days) and platelets>20x10(9)/l=16.5 days (range 11-42 days). At a median follow-up of 25 months, these transplanted patients remain well and in molecular complete remission.
authors.affiliation: Academic Department of Haematology and Oncology, University of Leeds, U.K.
authors.forename: F E
authors.initials: FE
authors.lastname: Davies
authors.forename: A C
authors.initials: AC
authors.lastname: Rawstron
authors.forename: G
authors.initials: G
authors.lastname: Pratt
authors.forename: R
authors.initials: R
authors.lastname: Coupe
authors.forename: D
authors.initials: D
authors.lastname: Clarke
authors.forename: A
authors.initials: A
authors.lastname: Lubenko
authors.forename: K
authors.initials: K
authors.lastname: Short
authors.forename: T J
authors.initials: TJ
authors.lastname: Perren
authors.forename: P J
authors.initials: PJ
authors.lastname: Selby
authors.forename: S
authors.initials: S
authors.lastname: Maclennan
authors.forename: K
authors.initials: K
authors.lastname: Major
authors.forename: V
authors.initials: V
authors.lastname: Woodhead
authors.forename: F
authors.initials: F
authors.lastname: Robinson
authors.forename: J A
authors.initials: JA
authors.lastname: Child
authors.forename: G M
authors.initials: GM
authors.lastname: Smith
authors.forename: P W
authors.initials: PW
authors.lastname: Johnson
authors.forename: G J
authors.initials: GJ
authors.lastname: Morgan
mesh_terms: D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000276:immunology; D016465:Bone Marrow Purging / Q000379:methods*; D001943:Breast Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy; D005260:Female; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology* / Q000473:pathology; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology
chemical_list: D018952:Antigens, CD34