title: Collection of autologous monocytes for dendritic cell vaccination therapy in metastatic melanoma patients.
abstract: BACKGROUND
  Dendritic cells (DCs) for immunotherapy of malignant melanoma can be generated from partially enriched monocytes prepared from PBMNCs. The feasibility of a single steady-state leukapheresis procedure to enrich monocytes for a complete vaccination series with up to 10 vaccinations was investigated.
  
  
  METHODS
  Thirty-eight patients (27 males and 11 females) with metastatic melanoma were enrolled in the study. All leukapheresis procedures were performed by a continuous flow method (Spectra, Cobe BCT) with a standard MNC program.
  
  
  RESULTS
  An average of 11.7 L (range, 8-14 L) of whole blood was processed within 197.3 +/- 23.7 minutes, and a mean of 13.5 +/- 5.7 x 109 WBCs in a final volume of 191.0 +/- 24.2 mL was collected. The MNC purity in the apheresis component was 81.5 +/- 15.1 percent, from which 29.8 +/- 14.7 percent were monocytes. Thus, 11.0 +/- 5.0 x 109 MNCs and 3.2 +/- 2.0 x 109 monocytes were collected per procedure. Linear regression analysis revealed a high correlation between the absolute number of monocytes in peripheral blood before the apheresis procedure and the number of monocytes in the collected component (r=0.74, p < 0.0001). For the generation of DCs, 1.6 +/- 0.8 x 109 MNCs were plated into culture dishes; 3.2 +/- 1.8 percent of the cultured cells matured to DCs, which resulted in 56.5 +/- 49.4 x 106 DCs (range, 6.3-178) per patient for the complete vaccination series.
  
  
  CONCLUSIONS
  A target dose of monocytes for the complete vaccination series could be obtained by a single convenient, safe, steady-state leukapheresis procedure in each patient without the need for G-CSF mobilization. The absolute number of monocytes in peripheral blood before the apheresis procedure is the best predictive variable for the yield of monocytes in the apheresis component.
authors.affiliation: Institute of Transfusion Medicine and Immunology, Red Cross Blood Service of Baden-Württemberg, Faculty of Clinical Medicine Mannheim, Germany. x.nguyen@blutspende.de
authors.forename: Xuan Duc
authors.initials: XD
authors.lastname: Nguyen
authors.forename: Hermann
authors.initials: H
authors.lastname: Eichler
authors.forename: Antje
authors.initials: A
authors.lastname: Sucker
authors.forename: Udo
authors.initials: U
authors.lastname: Hofmann
authors.forename: Dirk
authors.initials: D
authors.lastname: Schadendorf
authors.forename: Harald
authors.initials: H
authors.lastname: Klüter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D006801:Humans; D007167:Immunotherapy; D007937:Leukapheresis; D007958:Leukocyte Count; D008297:Male; D008545:Melanoma / Q000097:blood / Q000628:therapy*; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D010976:Platelet Count