Background: Recent studies have shown that interleukin-3 receptor alpha (CD123) is highly expressed on leukemia stem cells of patients with acute myeloid leukemia, and is correlated with tumor load and poor prognosis. The expression of CD123 may also be high in patients with myelodysplastic syndrome (MDS). In this study, the expression and clinical significance of CD123 and granulocyte colony stimulating factor (G-CSF) receptor (CD114) on the bone marrow cells of patients with MDS were investigated to explore the molecular marker of the malignant clone of MDS.
Methods: Forty-two patients with MDS, who were diagnosed in the Hematological Department of General Hospital of Tianjin Medical University from 2008 to 2009, and twelve normal controls were enrolled in this study. Fluorescence activiated cell sorter (FACS) was used to measure the expression of CD123 on CD34(+)CD38(-) cells and CD114 on CD34(+) cells of the bone marrow of these patients and controls and the clinical significance was analyzed. The expression of CD114 on CD123(+)CD34(+)CD38(-) cells was further measured to explore the molecular marker of the malignant clone in MDS.
Results: MDS patients displayed significantly higher proportion of CD34(+)CD38(-)/CD34(+) ((14.03 +/- 5.27)%) than normal controls ((7.70 +/- 4.36)%, P < 0.05). The expression rate of CD123(+)CD34(+)CD38(-)/CD34(+)CD38(-) was significantly higher in MDS patients ((48.39 +/- 28.15)%) than that in normal controls ((8.75 +/- 11.71)%, P < 0.01). The expression level of CD123 was significantly correlated with the proportion of bone marrow blasts (r = 0.457, P < 0.05). The expression rate of CD114(+)CD34(+)/CD34(+) was lower in MDS patients ((33.05 +/- 21.71)%) than that in normal controls ((38.99 +/- 19.07)%) but was not statistically significant (P > 0.05). The expression of CD114 on CD123(+)CD34(+)CD38(-) cells ((34.82 +/- 29.58)%) was significantly lower than that on CD123(-)CD34(+)CD38(-) cells ((53.48 +/- 27.41)%) of MDS patients (P < 0.05).
Conclusions: MDS patients displayed higher proportion of CD34(+)CD38(-)/CD34(+) than normal controls. CD123 was highly expressed in the bone marrow of the patients with MDS, significantly correlated with the proportion of bone marrow blasts, and thus might be the marker of MDS malignant clone. CD123(+)CD34(+)CD38(-) cells exhibited lower expression of G-CSF receptors, which might partly explain why MDS clone responds worse to G-CSF in vitro and in vivo.