Isolation of CD34+ progenitor cells from peripheral blood by use of an automated immunomagnetic selection system: factors affecting the results.
BACKGROUND
The isolation of CD34+ cells from mobilized peripheral blood is being increasingly used in the setting of allogeneic or autologous hematopoietic cell transplantation. Investigation of variables that may influence the effectiveness of CD34+ cell selection is of interest.


METHODS
Fifty-one CD34+ cell selections from peripheral blood progenitor cells (PBPCs) (39 allogeneic and 12 autologous) were performed using a magnetic cell separator (Isolex 300i, Baxter), including version 2.0 software. The results obtained were analyzed for different processing variables. The feasibility of transplanting these isolated CD34+ cells was also analyzed.


RESULTS
The isolated CD34+ cell fraction had a median purity of 88.9 percent (range, 47.8-98.3). The median recovery of CD34+ cells was 45.1 percent (13.8-76.2), and the median colony-forming unit- granulocyte-macrophage (CFU-GM) content was 17. 2 percent (0.8-58.6). Logarithms of T- and B-cell depletion had median values of 3.7 and 2.8, respectively. The version 2.0 software of the Isolex 300i gave a higher CD34+ cell recovery in the enriched cell fraction (median 57.8%) than did version 1.11 (39.4%) or 1.12 (44.4%) (p = 0.01). The use of recombinant human deoxyribonuclease I during cell processing yielded more CD34+ cells (53% vs. 41%, p = 0. 01) and higher purity (92.8% vs. 87%, p = 0.03). There was a correlation between the percentage of CD34+ cells labeled with the monoclonal antibody 8G12 clone and the percentage of CD34+ cells labeled with the monoclonal antibody used during the processing technique (9C5 clone) in the initial, enriched, and depleted CD34+ cell fractions (R(2) = 0.95; 0.92; 0.78, p< 0.005, respectively). Median times for recovering >0.5 x 10(9) per L of granulocytes and >20 x 10(9) per L of platelets were 13 and 16 days in the allograft patients and 13 and 14 days in the autograft patients.


CONCLUSIONS
CD34+ cells can be highly and effectively isolated from allogeneic and autologous grafts by use of this automated technique, with a high grade of T- and B-cell depletion. These purified CD34+ cell components can engraft normally.
Martín-Henao
G A
GA
Department of Cryobiology and Cell Therapy, Cancer Research Institute, Barcelona, Spain. gmartinh@iro.es
Picón
M
M
Amill
B
B
Querol
S
S
González
J R
JR
Martínez
C
C
Martino
R
R
Ferrá
C
C
Brunet
S
S
Grañena
A
A
Sierra
J
J
García
J
J
D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000097:blood*; D003114:Colony-Forming Units Assay; D015925:Cryopreservation; D005260:Female; D006098:Granulocytes / Q000637:transplantation; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged
D018952:Antigens, CD34