title: Simultaneous immunomagnetic CD34+ cell selection and B-cell depletion in peripheral blood progenitor cell samples of patients suffering from B-cell non-Hodgkin's lymphoma.
abstract: The reduction of residual tumor cells is one of the main targets of leukapheresis product (LP) processing. Immunomagnetic enrichment/selection of CD34+ progenitor cells (Baxter Isolex 300i) can achieve a reduction of contaminating B-cells of approximately 2-3 logs in B-cell non-Hodgkin's lymphoma patients. Specific release of the enriched CD34+ cells (stem cell releasing agent PR34+; Baxter) and the use of antibody-coated immunobeads targeted against B-cell markers (CD10, CD19, CD20, CD22, CD23, and CD37) during this procedure allows the GMP-like simultaneous capture of residual B cells within a closed system. This combination of two purging techniques enhances the B-cell depletion capacity up to 4.5 logs. By performing 10 clinical-scale purging procedures, we could show that the simultaneous immunomagnetic purging method is easy to perform and highly efficient. We evaluated B-cell log depletion by flow cytometry for cases with marker-positive cells detectable before and after the purging procedure. The mean reduction of B-cells in these cases was 3.5 logs; the mean CD34+ cell yield and purity were 47 and 92%. Using three LPs, we tested the procedure on a modified Baxter Isolex 300i device with software adaptations for this procedure (software version 2.0) in direct comparison with CD34+ cell selection only, using the former version (version 1.12). The CD34+ cell yield was 49% (40-54%) for the CD34+ cell selection and 51% (19-72%) for simultaneous double selection. The mean purity was 96% for CD34+ cell selection and 98% for simultaneous double selection. B-cell depletion was 1.9 logs for CD34+ cell selection, and after simultaneous double selection, the B-cell content was decreased by 3.7 log steps (P = 0.0495). Clinical application of double-purged cells has not prolonged the hematopoietic recovery times after high-dose therapy as compared with nonpurged peripheral blood progenitor cell autotransplants. In conclusion, we could show that the simultaneous double selection protocol developed leads to a highly increased B-cell purging efficacy when compared with CD34+ cell selection without any negative effects regarding CD34+ cell yield and engraftment times after high-dose therapy.
authors.affiliation: Department of Medicine/Hematology and Oncology, University of Münster, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Mohr
authors.forename: F
authors.initials: F
authors.lastname: Dalmis
authors.forename: E
authors.initials: E
authors.lastname: Hilgenfeld
authors.forename: E
authors.initials: E
authors.lastname: Oelmann
authors.forename: M
authors.initials: M
authors.lastname: Zühlsdorf
authors.forename: K
authors.initials: K
authors.lastname: Kratz-Albers
authors.forename: A
authors.initials: A
authors.lastname: Nolte
authors.forename: C
authors.initials: C
authors.lastname: Schmitmann
authors.forename: D
authors.initials: D
authors.lastname: Onaldi-Mohr
authors.forename: U
authors.initials: U
authors.lastname: Cassens
authors.forename: H
authors.initials: H
authors.lastname: Serve
authors.forename: W
authors.initials: W
authors.lastname: Sibrowski
authors.forename: J
authors.initials: J
authors.lastname: Kienast
authors.forename: W E
authors.initials: WE
authors.lastname: Berdel
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002470:Cell Survival / Q000502:physiology; D018572:Disease-Free Survival; D005434:Flow Cytometry; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods; D007937:Leukapheresis / Q000379:methods; D008212:Lymphocyte Depletion; D016393:Lymphoma, B-Cell / Q000276:immunology*; D013234:Stem Cells / Q000276:immunology*; D016896:Treatment Outcome
chemical_list: D018952:Antigens, CD34