[Effect of G-CSF on the proliferation and differentiation of bcr/abl(+)-CD34+ cells from CML patients].

Objective: To study the effect of granulocyte colony-stimulating factor (G-CSF) on the proliferation and differentiation of bcr/abl(+)-CD34+ cells.

Methods: bcr/abl(+)-CD34+ cells were isolated from bone marrow of chronic myelocytic leukemia (CML) patients and were treated with 0, 10, 100, 1000 ng/ml of G-CSF for 48, 96, 144 hs. CD34 cells from normal bone marrow were used as controls. Cell proliferation was determined by trypan blue dye exclusion, cell-cycle and antigen differentiation were determined by flow cytometry and cell morphology was observed under light microscope.

Results: The number of bcr/abl(+)-CD34+ cells was increased obviously in all groups. After cultured for 48 and 96 h, the number of bcr/abl(+)-CD34+ cells at G-CSF 10 ng/ml group was significantly higher than that in G-CSF 0 ng/ml group (P < 0.05) , the number of normal CD34 cells was increased only in the presence of G-CSF. After cultured for 48, 96 and 144 h, the cell number in G-CSF 100 ng/ml group was significantly higher than that in G-CSF 0 ng/ml group (P < 0.05, P < 0.01, P < 0.01, respectively). After cultured for 144 h, the cell percentages in G0/G1 phase for bcr/abl(+)-CD34+ cells in G-CSF 10, 100, 1000 ng/ml groups were significantly less than that in G-CSF 0 ng/ml group (P < 0. 05), and that for normal CD34 cells in G-CSF 10, 100, 1000 ng/ml groups were significantly less than that of G-CSF 0 ng/ml group after cultured for 48 and 96 h. The expressions of CD34 on bcr/abl(+)-CD34+ cells and normal CD34+ cells were decreased along with the culture duration, accompanied by the expression of CD33 and CD13 increased first and decreased later, which was not correlated with the concentration of G-CSF. Both bcr/abl(+)-CD34+ cells and normal CD34+ cells showed mature morphology along with proliferation and differentiation.

Conclusions: G-CSF promotes proliferation of both bcr/abl(+)-CD34+ cells and normal CD34+ cells, but not necessary for the former, and the former differentiates more rapidly than the latter does, but both was independent of G-CSF.