title: A rationale for positive selection of peripheral blood stem cells in multiple myeloma: highly purified CD34+ cell fractions of leukapheresis products do not contain malignant cells.
abstract: In multiple myeloma (MM), the presence of tumor cells in leukapheresis products (LP) has been demonstrated with highly sensitive molecular biological tools in up to 100% of cases. Therefore methods to reduce the tumor load of LP by CD34+ selection are envisaged. However, there is controversy as to whether the CD34+ cell is already involved in the malignant process. We have established a PCR assay with allele-specific oligonucleotide primers (ASO) complementary to the CDR3-hypervariable region of the immunoglobulin heavy chain gene of each patient's myeloma clone. Using this ASO-PCR, 43 LP of 10 patients with MM eligible for high-dose therapy were assessed for malignant cells. Furthermore, in an experimental setting we have examined 10 CD34+ and four CD19+ fractions obtained from PCR-positive LP by sequential preparative magnetic and fluorescence activated cell sorting (purity >96%) for the presence of the tumor-specific CDR3 region. The majority of LP harbored cells of the myeloma clone (93%), while all CD34+ fractions were PCR-negative. In all CD19+ fractions malignant cells were detected. These results confirm that CD34+ selection can be considered for LP in MM. The sensitivity of the ASO-PCR (up to 10[-5]) enables us further to monitor the efficacy of CD34+ enrichment protocols in the clinical setting.
authors.affiliation: Department of Internal Medicine V, University of Heidelberg, Germany.
authors.forename: F W
authors.initials: FW
authors.lastname: Cremer
authors.forename: K
authors.initials: K
authors.lastname: Kiel
authors.forename: C
authors.initials: C
authors.lastname: Sucker
authors.forename: J
authors.initials: J
authors.lastname: Wacker
authors.forename: A
authors.initials: A
authors.lastname: Atzberger
authors.forename: R
authors.initials: R
authors.lastname: Haas
authors.forename: H
authors.initials: H
authors.lastname: Goldschmidt
authors.forename: M
authors.initials: M
authors.lastname: Moos
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000097:blood; D018952:Antigens, CD34 / Q000097:blood*; D001483:Base Sequence; D017931:DNA Primers; D005260:Female; D005803:Genes, Immunoglobulin; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007937:Leukapheresis / Q000379:methods; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009101:Multiple Myeloma / Q000235:genetics / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000235:genetics
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D017931:DNA Primers; D007143:Immunoglobulin Heavy Chains; D017260:Receptor-CD3 Complex, Antigen, T-Cell