급성백혈병에서 화학요법후 가동화되는 말초혈액 CD34+세포와 CFU-GM의 역동적 분석 및 CD34+ 세포아형에 관한 연구

Abstract

Background: Recently, analysis of CD34 surface antigen expression has been proposed as a precise and valuable method for quantifying blood progenitor cells. Determination of optimum protocols for harvesting peripheral blood stem cells can be expected to be possible with this method irrespective of remarkable interindivisual heterogeneity in timing, extent, and duration of mobilization. In this study, we have evaluated the kinetics of mobilization of CD34+ cells and its phenotypic subsets, and analysed correlation between the CD34+ cells and the in vitro CFU-GM concurrently on peripheral blood samples from patients with acute leukemia in complete remission underwent various myelouppressive chemotherapy or myclosuppressive chemotherapy plus GM-CSF. Methods: Peripheral blood levels of CD34+ cells, phenotypic subsets of CD34+ cells and CFU-GM were studied serially in 19 patients with acute leukemia in remission during the periods of recovery that followed induction consolidation chemotherapy using flow cytometry direct immunofluorescence method, and in vitro progenitor cell assay, respectively. Results: Sixteen of nineteen patients(84%) showed a significant increment of CD34+ cells following myelosuppressive chemotherapy. However, there was a wide variation among patients with respect to the extent and timing of CD34+ cells mobilizations. According to the dual color immunofluorescence analysis, circulating blood CD34+ cells were predominantly CD34+/HLA-DR+, and CD34+/CD38+, whereas the expression of CD34+/HLA-DR-, CD34+/CD38-, and CD34+/CD33- cells were observed earlier in the recovery phase in some patients. The levels of peripheral blood CD34+ cells in patients with chemotherapy/GM-CSF were significantly higher than those with chemotherapy-induced mobilization(p<0.05). The highest levels of CD34+ cells were observed in patients underwent intensive consolidation chemotherapy plus GM-CSF for the first complete remission. A significant correlation (r=0.9099) was observed between circulating CFU-GM per mL (Day 14) and flow cytometric determination of total CD34+ cells per mL of blood. The appearance of CD34+ cells preceded the increase of CFU-GM by 24 to 48 hours. Conclusion: Flow cytometric analysis of CD34+ cells and its phenotypic subsets allows the rapid quatification and qualitative characterization of peripheral blood hematopoietic progenitor cells that shows remarkable interpatient heterogeneity. Estimation of CD34+ cells can replace advantageously the classic CFU-GM assay and can allow us to optimize peripheral blood stem cell collection on a real-time basis in patients with acute leukemia. Administration of GM-CSF after chemotherapy resulted in a significant enhancement of circulating CD34+ cells. But the possibility of mobilization of leukemic progenitor cells should be evaluated.