title: Selection and transplantation of autologous CD34+ B-lineage negative cells in advanced-phase multiple myeloma patients: a pilot study.
abstract: The feasibility of sequential positive and negative selection of mobilized CD34+ B-lineage negative cells to achieve tumour-free autografts in multiple myeloma (MM) patients was evaluated. Peripheral blood stem cells (PBSC) of 14 patients with advanced disease were mobilized. CD34+ cells were enriched in 12 of the patients by the avidin-biotin immunoabsorption technique. Subsequently, CD10+, CD19+, CD20+ and CD56+ cells (B-lin cells) were removed by immunomagnetic depletion. Minimal residual disease (MRD) was detected by flow cytometry and PCR-based molecular analysis of the patient specific IgH complementary-determining region III (CDRIII). Positive selection of stem cells produced a median recovery of 54.7% of the initial content of CD34+ cells (median purity 71.9%). Negative depletion of B-lineage cells reduced the number of CD34+ cells to 33.3% of the baseline value (median purity 72.7%). However, long-term culture assays showed the recovery of >60% of primitive haemopoietic progenitor cells after depletion of the B-lineage-positive cells. All evaluable patients had detectable disease in PBSC collections. The first step of positive selection of CD34+ cells resulted in >2 logs of tumour cell purging. However, molecular assessment showed the persistence of the disease in 6/7 cases. Immunofluorescence analysis demonstrated 1 additional log of B-cell purging by negative depletion. More importantly, molecular evaluation of IgH CDRIII region showed the disappearance of myeloma cells in 6/7 patients. 12 patients received a median of 3.9 x 106 CD34+ B-lin- cells/kg after conditioning with high-dose melphalan and showed a rapid reconstitution of haemopoiesis. These results were similar to two similar cohorts of patients who received either unmanipulated PBSC or positively selected CD34+ cells after the same conditioning regimen. Severe extrahaematological toxicity was limited to mucositis; no late infections were observed. We concluded that autotransplantation of purified CD34+ B-lin- cells was associated with a rapid and sustained recovery of haemopoiesis and low peritransplant morbidity. Sequential positive and negative enrichment of stem cells reduced tumour cell contamination in B-cell malignancies below the lower limit of detection of molecular analysis.
authors.affiliation: Institute of Haematology and Medical Oncology 'L. & A. Seràgnoli', University of Bologna, Bologna, Italy. rmlemoli@med.unibo.it
authors.forename: R M
authors.initials: RM
authors.lastname: Lemoli
authors.forename: G
authors.initials: G
authors.lastname: Martinelli
authors.forename: A
authors.initials: A
authors.lastname: Olivieri
authors.forename: M R
authors.initials: MR
authors.lastname: Motta
authors.forename: S
authors.initials: S
authors.lastname: Rizzi
authors.forename: C
authors.initials: C
authors.lastname: Terragna
authors.forename: G
authors.initials: G
authors.lastname: Leopardi
authors.forename: M
authors.initials: M
authors.lastname: Benni
authors.forename: S
authors.initials: S
authors.lastname: Ronconi
authors.forename: I
authors.initials: I
authors.lastname: Cantori
authors.forename: D
authors.initials: D
authors.lastname: Rondelli
authors.forename: S
authors.initials: S
authors.lastname: Mangianti
authors.forename: P
authors.initials: P
authors.lastname: Leoni
authors.forename: M
authors.initials: M
authors.lastname: Montanari
authors.forename: M
authors.initials: M
authors.lastname: Cavo
authors.forename: S
authors.initials: S
authors.lastname: Tura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000378:metabolism*; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D005260:Female; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000628:therapy*; D018365:Neoplasm, Residual / Q000175:diagnosis; D010865:Pilot Projects; D014182:Transplantation, Autologous
chemical_list: D018952:Antigens, CD34