title: Mobilized CD34+ cells selected as autografts in patients with primary light-chain amyloidosis: rationale and application.
abstract: BACKGROUND
  Concern about tumor cell contamination in stem cell preparations has led to the use of CD34+ cell selection as a means of purging. Increasing the number of CD34+ cells per leukapheresis may help to provide an adequate dose of CD34+ cells.
  
  
  METHODS
  The reverse transcriptase polymerase chain reaction (RT-PCR) was employed to clone overexpressed clonotypic immunoglobulin light-chain variable region genes (Ig VL) from bone marrows of patients with primary light-chain amyloidosis (AL). Patient-specific primers were designed to evaluate stem cell collections for contamination. CD34+ cell selection was performed on components from AL patients who underwent mobilization with granulocyte-colony-stimulating factor (G-CSF) (filgrastim; 16 microg/kg/d for 4 days) and collection by large-volume leukapheresis (LVL;25L) on Days 4 and 5. The selected cells alone were transfused after patients received mephalan (200 mg/m2).
  
  
  RESULTS
  Contamination was found in collections from 4 to 7 patients, which provided the rationale for a subsequent trial of CD34+ cell selection. The median number of CD34+ cells per kg collected on Days 4 and 5, and in toto, was 4.0 x 10(6)(1.1-12.7), 7.9 x 10(6)(1.8-12.7), and 10.7 x 10(6)(2.9-25.4), respectively (n = 9 patients). The median yield per selection was 38 percent, with a purity of 85 percent (45-97%), and the viability of CD34+ cells averaged 96.4 +/- 3.6 percent (n = 18 selections). The median number of CD34+ cells infused was 5.9 x 10(6) per kg (2.1-10.1). In comparison with AL patients given unselected autografts, patients receiving selected CD34+ cells experienced similar reconstitution of neutrophils and platelets but slower lymphocyte recovery.
  
  
  CONCLUSIONS
  Patients with AL often have contamination with clonotypic cells in their blood autografts. G-CSF mobilization and LVL provide components that allow the selection of adequate doses of CD34+ cells. The use of CD34+ cells in patients with AL achieves rapid neutrophil and platelet recovery but delayed lymphocyte recovery. CD34+ cell selection is feasible in the treatment of AL, but its effectiveness in purging clonotypic cells remains to be ascertained.
authors.affiliation: Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston University School of Medicine, Masschusetts 02118-2393, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Comenzo
authors.forename: D
authors.initials: D
authors.lastname: Michelle
authors.forename: M
authors.initials: M
authors.lastname: LeBlanc
authors.forename: J
authors.initials: J
authors.lastname: Wally
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: G
authors.initials: G
authors.lastname: Kica
authors.forename: S
authors.initials: S
authors.lastname: Karandish
authors.forename: C F
authors.initials: CF
authors.lastname: Arkin
authors.forename: D G
authors.initials: DG
authors.lastname: Wright
authors.forename: M
authors.initials: M
authors.lastname: Skinner
authors.forename: J
authors.initials: J
authors.lastname: McMannis
mesh_terms: D000328:Adult; D000686:Amyloidosis / Q000628:therapy*; D018952:Antigens, CD34 / Q000097:blood*; D002469:Cell Separation; D002999:Clone Cells; D015331:Cohort Studies; D017931:DNA Primers; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007937:Leukapheresis / Q000379:methods; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019172:Transplantation Conditioning / Q000379:methods; D014182:Transplantation, Autologous
chemical_list: D018952:Antigens, CD34; D017931:DNA Primers; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D016179:Granulocyte Colony-Stimulating Factor