目的：研究地塞米松(DXM)对恶性造血细胞表面rnFlt3受体表达及重组人Flt3配体(rhFL)介导的恶性rn造血细胞增殖的影响。方法：采用流式细胞仪分析rn18株恶性造血细胞系细胞和10例新鲜白血病原代rn细胞表面Flt3受体的表达，及与DXM 0.1μmol/Lrn共育24h后Flt3受体的表达，用MTT法测定DXMrn对rhFL介导的恶性造血细胞增殖的影响。结果：rn(1)恶性造血细胞系细胞和白血病原代细胞Flt3受rn体的表达广泛并呈多样性。(2)恶性细胞表面Flt3rn受体的表达与rhFL介导的恶性细胞增殖无一定相关rn性，rhFL促进部分Flt3受体阴性细胞的增殖。(3)rnDXM下调Flt3受体的表达，抑制rhFL介导的部分rn恶性造血细胞系细胞和新鲜白血病原代细胞的增rn殖。结论：DXM可下调恶性造血细胞表面Flt3受rn体的表达，抑制rhFL介导的恶性造血细胞的增殖。rnDXM和rhFL联合应用，可使rhFL在恶性造血系统rn疾病的造血功能缺乏治疗时更为安全。%AIM: To investigate the effect of dexamethasone rn(DXM) on the expression of Flt3 receptor and the prolifrneration mediated by recombinant human Flt3 ligand rn(rhFL) in leukemia cells. METHODS: Eighteen marnlignant hematopoietic cell lines and 10 leukemia blasts rnfrom leukemia patients were examined by flow cytometry rnfor the expression of Flt3 receptor before and after incubarntion with DXM 0.1 μmol/L for 24 h. The effect of rnDXM on the proliferation of malignant hematopoietic cells rnwas measured by MTT assay. RESULTS: (1) Expresrnsion of the Flt3 receptor in malignant hematopoietic cell rnlines and leukemia blasts was widespread and extremely rnheterogeneous; (2) The presence of receptor on the surrnface of malignant hematopoietic cell didn't necessarily imrnply a significant ligand-induced response, at least in terms rnof proliferation. Conversely, some Flt3 receptorrnnegative malignant hematopoietic cells responded to rnrhFL; (3) DXM down-regulated the expression of Flt3rnreceptor and inhibited the proliferation induced by rhFL in rnsome malignant hematopoietic cell lines and fresh rnleukemia cells. CONCLUSION: DXM may downrnregulate the expression of Flt3 receptor on the surface of rnmalignant hematopoietic cells and inhibit the proliferation rninduced by rhFL. A combination of rhFL and DXM rnmay serve to control hematopoietic defects in malignant rnhematopoietic diseases.
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