Difference between expression of adhesion molecules on CD34+ cells from bone marrow and G-CSF-stimulated peripheral blood

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 mu g/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.