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.
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.
Mohr
M
M
Department of Medicine/Hematology and Oncology, University of Münster, Germany.
Dalmis
F
F
Hilgenfeld
E
E
Oelmann
E
E
Zühlsdorf
M
M
Kratz-Albers
K
K
Nolte
A
A
Schmitmann
C
C
Onaldi-Mohr
D
D
Cassens
U
U
Serve
H
H
Sibrowski
W
W
Kienast
J
J
Berdel
W E
WE
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
D018952:Antigens, CD34