Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods.
BACKGROUND
Malignant cells may contribute to relapse after autologous hematopoietic cell transplantation The effectiveness of a double immunomagnetic purging strategy combining CD34-positive with B-negative cell selection to purge peripheral blood progenitor cells (PBPCs) from patients with chronic lymphoproliferative disorders has been analyzed.


METHODS
Twenty-two CD34+ cell selections from patients with follicular lymphoma (n = 14), chronic lymphocytic leukemia (n = 6), mantle cell lymphoma (n = 1), and splenic marginal zone lymphoma (n = 1) were performed by use of a magnetic cell selector followed by a negative cell selection step with anti-CD19 monoclonal antibody bound to immunomagnetic beads.


RESULTS
The PBPC components contained median CD34+ cells of 1.24 percent (range, 0.38-3.92%) and CD19+ cells of 1.83 percent (range, 0.06-69.7%). After positive selection (n = 22), 49 percent (range, 16-72%) of CD34+ cells were recovered with a purity of 93 percent (range, 24-99%). The double-positive and -negative selections (n = 20) yielded 57.5 percent of CD34+ cells (range, 33.4-79.4%) with a purity of 95 percent (range, 63-99%). Logarithms of B-cell reduction in the CD34+-cell-enriched B-cell-depleted component had a median value of 3.63 (range, 2.74-4.84 log) and CD19+ and CD5+ cells for chronic lymphocytic leukemia patients with more than 4.56 log (>3.6-5.6 log). Of 13 PBPC components that had a tumor-specific clonal signal, 10 became PCR negative after the double-selection procedure.


CONCLUSIONS
Combined positive and negative magnetic cell selection achieves a high grade of tumor cell reduction with up to 77 percent of the grafts being negative for tumor-specific clonal signal by PCR analysis. This technique preserves an adequate recovery of progenitor cells able to engraft.
Martín-Henao
G A
GA
Department of Cryobiology and Cell Therapy, Duran and Reynals Hospital, Barcelona, Spain. gmartinh@iro.es
Picón
M
M
Rueda
F
F
Amill
B
B
Querol
S
S
Gonzalez-Barca
E
E
Ferrá
C
C
Grañena
A
A
García
J
J
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D018941:Antigens, CD19 / Q000276:immunology; D018952:Antigens, CD34 / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D003114:Colony-Forming Units Assay; D015925:Cryopreservation; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D018189:Immunomagnetic Separation / Q000592:standards; D007937:Leukapheresis / Q000379:methods; D008232:Lymphoproliferative Disorders / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D033581:Stem Cell Transplantation / Q000379:methods / Q000592:standards; D014182:Transplantation, Autologous / Q000379:methods / Q000592:standards
D000911:Antibodies, Monoclonal; D018941:Antigens, CD19; D018952:Antigens, CD34