Difference between Expression of Adhesion Molecules on CD34 + Cells from Bone Marrow and G‐CSF‐Stimulated Peripheral Blood

Abstract

Three‐color immunofluorescence cytometry was used to quantify the expression of different adhesion molecules on CD34⁺ cells of steady‐state bone marrow (BM) and peripheral blood stem cells (PBSC) after mobilizing with G‐CSF (10 μg/kg/body weight) in nine cancer patients undergoing high‐dose chemotherapy with subsequent autologous blood stem cell rescue. The expression rate of each adhesion molecule on CD34⁺ cells showed great inter‐individual variations. High expression (>50%) on CD34⁺ cells from PBSC and BM was found for CD58 (leukocyte function‐associated antigen‐3), CD31 (platelet‐endothelial cell adhesion molecule‐1), CD11a (leukocyte function‐associated antigen‐1) and CD49d (very late activation antigen‐4); a moderate expression (20%‐40%) was seen for CD49e (very late activation antigen‐5), CD62L (leukocyte‐endothelial cell adhesion molecule), CD54 (ICAM‐1) and CD117 (c‐kit). c‐kit, CD58, CD62L and CD49d were less expressed on CD34⁺ cells of PBSC than of BM, the difference being statistically significant for CD49d (p < 0.05). CD49e and CD37 were expressed more in PBSC than BM without being statistically significant. The mean fluorescence intensity for all adhesion molecules on CD34⁺ cells did not differ significantly between PBSC and BM. The significantly lower expression of CD49d on G‐CSF‐mobilized PBSCs might suggest that downregulation of this molecule may be involved in the process of peripheral stem cell mobilization.