BACKGROUND & OBJECTIVE: Dendritic cells (DCs) or DClike cells had been successfully induced in vitro from leukemia cells, which may provide a promising immunotherapeutic protocol for leukemia. This study was designed to investigate the efficiency of in vitro generation of dendritic cells from CD14+ acute myelomonocytic (M4) or monocytic (M5) leukemia cells and their ability of stimulating specific antileukemia T-cell response.METHODS: Bone marrow mononuclear cells (BMMNCs) were isolated from 5M4/M5 leukemia patients with high CD14 expression, and then divided into 3groups: adherent leukemia cells, nonadherent blasts, and total unfractioned blasts. CD14 expression of the 3 groups was evaluated by flow cytometry (FCM). When cultured with or without granulocyte-macrophage colonystimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-α) for 7-10 days, monocytic leukemia cell-derived dendritic cells (Mo-LDCs) were identified through morphologic observation and immunophenotype analysis using FCM. The immune function of Mo-LDCs was detected through allogeneic mixed lymphocyte reaction (Allo-MLR) and cytotoxicity assay of antileukemia cytotoxic T lymphocytes (CTLs). The leukemic origin of Mo-LDCs was confirmed by chromosomal karyotype analysis combined with the aberrant expression of myeloid antigens. RESULTS: The amount of CD14+ cells, which could differentiate into CD83+ mature DCs under induction of the cytokine combination, was higher in adherent leukemia cells than in nonadherent blasts and total unfractioned blasts. Regarding each 3 cell groups of the same patient or the unfractioned blasts of various patients, initial CD14 expression was positively related to the yield of CD83 + DCs after induction (r=0.967, P=0.007). Mo-LDCs exhibited typical morphology and phenotype as mature DCs, induced potent proliferation of homogeneous T cells in Allo-MLR, stimulated the expansion of leukemia-specific CTLs, and continued to possess the cytogenetic abnormalities of the original leukemia, as well as the aberrant expression of myeloid antigens. CONCLUSIONS: In M4/M5 subtype of AML, CD14+ cells could differentiate into immune-competent Mo-LDCs under the induction of the cytokine combination. CD14 expression level may predict the DCs differentiation ability of monocytic leukemia. MoLDCs, which possess the classical phenotype and function of DCs, as well as the abnormal leukemic antigens, may be useful for the immunotherapy of M4/M5 AML.%背景与目的:白血病细胞能在体外分化为树突细胞(dendritic cells,DCs),从而有希望用于白血病的免疫治疗.本研究旨在探讨CD14高表达的单核细胞系白血病(M4、M5)细胞分化而来的DCs体外诱导抗白血病T细胞应答的能力.方法:取5例初诊CD14高表达的M4或M5型白血病患者的骨髓标本,分离单个核细胞(bone marrow mononuclearcells,BMMNCs),将白血病细胞分为3组:贴壁白血病细胞组、非贴壁白血病细胞组及总白血病细胞组.流式细胞术(flow cytometry,FCM)比较3组细胞的CD14表达.用含GM-CSF、IL-4和TNF-α或不含细胞因子的培养液培养细胞7～10天后,通过细胞形态学观察及FCM检测细胞表型,鉴定单核白血病细胞来源的DCs(monocytic leukemia cell-derived dendritic cells,Mo-LDCs);采用异基因混合淋巴细胞反应(allogeneic mixed lymphocyte reaction,Allo-MLR)以及细胞毒性T淋巴细胞(cytotoxic T lymphocytes,CTL)抗白血病细胞毒分析检测Mo-LDCs的免疫功能,染色体核型分析结合异常表面抗原确定Mo-LDCs的白血病来源.结果:3组中贴壁白血病细胞的CD14含量最高,在细胞因子联合诱导下,可分化为大量CD83+成熟DCs.在同一病例的3组细胞以及不同病例的总单核细胞组间,培养前CD14的表达率与诱导后CD83+DCs的产率成正相关(r=0.967,P=0.007).Mo-LDCs具有典型的成熟DCs的形态及表型特征,在Allo-MLR中能刺激同种T细胞明显增殖,并能刺激扩增特异性抗白血病CTL.同时,Mo-LDCs持续存在所起源白血病的核型异常和异常表达的髓系抗原.结论:在细胞因子组合诱导下,M4、M5亚型AML的CD14+细胞可分化为具有免疫功能的Mo-LDCs,单核系白血病细胞的CD14表达高低可能预示其DCs分化能力.Mo-LDCs具有经典的DCs的表型及功能,还具有白血病的克隆异常,可用于M4、M5患者的免疫治疗.
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