急性粒-单核细胞白血病的免疫表型及细胞遗传学特征

背景与目的:白血病中某些抗原的表达与细胞遗传学的改变密切相关。本研究旨在探讨急性粒-单核细胞白血病(acutemyelomonocyticleukemia,M4)的免疫表型特征,并分析其与细胞遗传学的关系,为其诊断及治疗提供依据。方法:采用一组系列相关单克隆抗体和三色流式细胞术对81例M4患者进行免疫表型分析,并分析有核型资料的73例患者的核型异常;同时应用双色间期荧光原位杂交(fluorescenceinsituhybridization,FISH)技术对有染色体标本的35例患者进行inv(16)检测,并分析inv(16)阳性患者的免疫表型特征。结果:81例M4患者中48例(59.3%)表达干细胞标志CD34;髓系标志以CD33(84.0%)表达最高,其次为CD13(81.5%)和CD14(24.7%);分别有23例(28.4%)和10例(12.3%)患者表达T系和B系相关抗原。11例M4Eo患者中CD13均阳性,10例CD33阳性,7例CD34阳性,5例CD2阳性。FISH检测发现14例患者inv(16)阳性,其中CD13阳性13例,CD33阳性11例,CD34阳性8例,CD14阳性5例,CD7阳性3例,CD2阳性3例。73例M4患者中,异常染色体检出率为41.1%(30/73),共检出11种主要异常核型。CD2和CD34在染色体异常患者中表达明显增高,而CD14表达减低。CD2在M4Eo中表达增高,但其表达与inv(16)无显著性相关。结论:急性粒-单核细胞白血病以髓系抗原表达为主,CD2和CD34在染色体异常患者中表达明显增高;CD2在M4Eo中表达增高。Inv(16)在M4中占40%,各抗原表达与inv(16)无显著相关性。     

急性白血病首次复发后免疫表型及细胞遗传学改变

目的 :分析成人急性白血病首次复发前后免疫表型和细胞遗传学改变。方法 :采用间接荧光法分析急性白血病患者的免疫表型 ,用 G分带技术研究患者的染色体核型。结果 :5例中 4例急性淋巴细胞白血病 ( ALL )复发后的患者发生免疫表型变化 ,均涉及 CD3 4 抗原表达 ;CD3 4 抗原的表达与再诱导治疗结果呈负相关。 10 /12例急性髓细胞白血病 ( AML )复发患者免疫表型发生改变 ,涉及 CD1 4 、CD1 5 、CD1 3 、CD3 3 、CD3 4 、CD7、HLA-DR等抗原 ;CD1 4 、CD3 3 、CD3 4 发生改变的患者再诱导治疗效果差 ;CD1 5 由阴性转为阳性的患者再诱导效果较好。 7例患者复发前后均进行了染色体核型分析 ,4例出现主要的染色体核型改变 ,其中 3例为异常核型转为正常核型 ;染色体核型发生改变的病例再诱导治疗效果均较差。结论 :成人急性白血病复发后免疫表型和细胞遗传学均可发生改变 ,这些改变与再诱导治疗的结果有关。     

成人急性髓细胞性白血病免疫表型与细胞遗传学及临床特征的关系

背景与目的:新的WHO分类已迅速应用于白血病的诊断。依据多个系相关抗原的表达,多参数高分辨流式细胞术可准确地识别白血病细胞的系列来源和分化阶段,而且某些抗原表达与细胞遗传学改变和预后密切相关。本研究旨在探讨初治成人急性髓细胞性白血病(acutemyeloidleukemia,AML)的免疫表型特征,并对其与FAB分类、细胞遗传学和临床表现的关系进行分析。方法:采用多参数高分辨流式细胞术对96例成人AML患者骨髓进行免疫表型分析,染色体G显带技术对其中的73例进行核型分析。结果:AML患者中,某些免疫表型特征与FAB分类具有相关性,包括M3中缺乏表达HLA鄄DR、CD34和CD56,但CD2的表达增加;M2中CD19、M5中CD14和CD56的表达增加,而M0中未见MPO的表达。本组AML核型异常率为54.8%,其中CD22、CD56和TdT的表达与核型异常有显著性相关。10例t(8;21)改变仅见于M2中,并高表达CD15、CD19、CD34和CD56,但未见CD2和CD7表达。7例伴t(15;17)的M3患者中未见淋系抗原的表达。此外,CD4和TdT抗原的表达与患者年龄、CD7和CD14的表达与外周血白细胞计数、CD4、CD14和CD56的表达与血小板计数等均有显著性正相关。结论:AML患者免疫表型与细胞遗传学的相关性提示AML抗原的异常表达可能与基因的异常改变密切相关。白血病免疫表型的检测有助于     

流感疫苗促进髓系白血病骨髓细胞来源树突状细胞的功能

目的: 研究流感疫苗对髓系白血病骨髓源性树突状细胞（dendritic cells,DCs）功能的影响及其机制。方法：分离髓系白血病患者\[急性髓细胞白血病(acute myeloid leukemia, AML)19例, 慢性髓细胞白血病（chronic myeloid leukemia,CML) 8例\]骨髓单个核细胞（mononuclear cell,MNC）,用GMCSF和IL4诱导7 d,获得未成熟白血病DCs,然后加入全病毒灭活流感疫苗（whole inactivated influenza vaccine, WIV）、裂解病毒流感疫苗（split influenza vaccine,SIV）或TNFα继续培养24 h。R显带法分析DCs染色体核型,流式细胞仪检测DCs表型,ELISA法测定DCs培养上清IL12的水平,CCK8法检测DCs诱导的CTL对自体白血病细胞的细胞毒作用。结果：19例AML患者中的15例及8例CML患者的MNC全部成功诱导出DCs。与TNFα刺激的白血病DCs相比,流感疫苗刺激的白血病DCs表面分子（CD80、CD83、CD86、HLADR）表达明显上调（P<005）,培养上清中IL12的分泌水平明显增加（P<0.05）,其诱导的CTL可显著杀伤自体白血病细胞（P<0.05）;WIV刺激的DCs在表型、IL12分泌水平及细胞毒作用方面均较SIV刺激的DCs显著增高（P<0.05）。结论： 流感疫苗促进髓系白血病源DCs表型成熟及IL12的分泌,增强其诱导的CTL对自体白血病细胞的杀伤作用。     

232例急性髓细胞白血病免疫表型及与细胞遗传学关系分析

目的探讨初治成人急性髓细胞性白血病（acute myeloid leukemia,AML）的免疫表型特征,并对其与FAB分类、细胞遗传学的关系进行分析。方法采用CD45/SSC双参数散点图设门方法、三色流式细胞术对232例急性髓细胞白血病细胞进行免疫表型分析,染色体G显带技术对其中的172例进行核型分析。结果AML患者中,CD38、CD33和CD13的表达最常见,CD117、CD11b分别有助于区分髓系和淋系白血病,在淋系抗原中,以CD9、CD7较常见。CD7可能是一个独立的预后因素。某些免疫表型特征与FAB分类具有相关性,包括M3中缺乏表达HLA-DR和CD34,而CD9表达增加。CD11b有助于M5与M1、M2、M3的区分,M5中CD14的表达率增加,其阳性率明显高于M2。CD15可能有助于M5亚型的鉴别。本组AML核型异常率为71.6%,t（8;21）（q22;q22）主要见于M2（79.0%）,还见于M5。单纯t（8;21）（q22;q22）易位10例（52.6%）,伴其它染色体异常的为9例（47.4%）,主要附加异常染色体类型为性染色体的丢失。CD13、CD9的表达与染色体异常显著性相关。CD117、CD15同时表达的AML少有预后较差染色体的异常。伴t（8;21）（q22;q22）异常的AML表达CD15、CD33、CD38显著增加。结论白血病免疫表型的检测有助于AML的诊断和分类。免疫表型与细胞遗传学的相关性提示AML抗原的异常表达可能与基因的异常改变密切相关。     

树突状细胞体外高效诱导白血病特异性细胞毒性T淋巴细胞生成

[目的]研究体外诱导产生的细胞毒性T淋巴细胞(CTL)及其抗白血病反应.[方法]应用mGM-CSF及mIL-4细胞因子从小鼠骨髓细胞扩增出成熟树突状细胞(DC),使其负载冻融法制备的白血病细胞相关抗原(TAA),通过观察DC诱导的白血病特异性CTL的免疫表型,MTT分析其对于L7212细胞的抑制率,利用ELISA评价IL-2和IL-4水平.[结果]骨髓单个核细胞经mGM-CSF、mIL-4的联合作用7天后光镜及扫描电镜下观察到大量成熟DC生成.经负载TAA的DC活化后T细胞中CD3 、CD8 、CD25 细胞明显增多.FCM显示CD3 、CD8 、CD25 T细胞显著增多,CD8 细胞多于CD4 细胞.活化后T细胞对L7212细胞有特异性杀伤活性,在效靶比为50:1培养72 h后杀伤率达90.1%±2.7%.DC与T细胞共培养上清中IL-2的分泌水平为4.656±0.62pg/ml,明显高于普通T细胞培养组的1.436±0.11pg/ml(P=0.011),IL-4水平则无明显变化(P＞0.05).[结论] mGM-CSF及mIL-4配伍诱导生成的DCs经L7212冻融抗原负载后可在体外高效诱导白血病特异性CTL生成.     

急性髓系白血病M2型免疫表型及细胞遗传学研究

目的 探讨急性髓系白血病M2型的免疫表型及细胞遗传学特征.方法 采用一组单克隆抗体和三色流式细胞术对112例M3患者进行免疫表型及核型分析.结果 112例M3患者中,70例(62.5%)表达干细胞标志CD34.髓系标志中以CD13(87.5%)M2患者表达最高,其次是CD33(83.9%)和CD14(2.7%).分别有34例(30.4%)及24例(21.4%)患者表达T系及B系标志.112例M2患者中,73例(65.2%)检出异常核型,共检出28种数目异常,25种结构异常.47例(42.0%)患者检出t(8;21).CD19及CD34单独或共同表达在核型异常及伴t(8;21)的M2患者中显著增高(P＜0.05).结论 M3以髓系抗原表达为主,部分有淋系抗原表达,CD19及CD34表达与t(8;21)显著相关.     

髓系／NK前体细胞急性白血病1例的诊断分析

目的 分析1例髓系／NK前体细胞急性白血病（M／NKPAL）的诊断过程,提高对M／NKPAL的认识。方法 对1例M/NKPAL采用细胞涂片染色、细胞化学染色方法和流式细胞术进行细胞形态学和免疫表型分析,并应用细胞遗传学和PCR技术进行染色体核型分析及T细胞受体、白血病融合基因的检测,同时结合相关文献进行分析。结果骨髓原始细胞为90.4％,绝大部分白血病细胞形态学类似急性淋巴细胞白血病L2型,过氧化物酶染色阴性,偶见Auer小体。免疫表型为CD34、HLA-DR、CD33、CD7、CD56、CD38阳性和cyCD3弱表达,而cyMPO、CD3、CD4等阴性。存在染色体核型异常,未检测到克隆性T细胞受体基因重排和白血病相关的融合基因。结论M/NKPAL临床少见,诊断复杂,仅依据形态学难以诊断,应注意与伴有髓系抗原表达的T淋巴细胞白血病、急性髓细胞白血病微分化型、T／髓系混合表型急性白血病和母细胞性NK细胞白血病／淋巴瘤等相鉴别。     

不同亚型急性髓性白血病细胞转化为树突状细胞的研究

目的 :探讨利用一定组合的细胞因子 ,将不同亚型的急性髓性白血病 (acute m yeloidleukemia,AML)细胞在体外转化为树突状细胞 (dendritic cell,DC)。方法 :8例初发 AML 患者 (其中M1 1例、M2 a3例、M32例、M4 c1例、M51例 )的骨髓单个核细胞 (BMMNC) ,在含 GM- CSF、IL- 4和TNF-α的完全培养液中培养 14天 ,通过光镜及电镜下观察细胞形态、流式细胞仪测定细胞免疫表型和 MTT法混和淋巴细胞反应来鉴定 DC。结果 :6例患者的 BMMNC培养 14天后转化为 DC。 DC的免疫表型 CD1 a、CD83、CD86 、HL A- DR较培养前明显上调 (P<0 .0 5 )。 DC对同种异体 T淋巴细胞有较强的刺激作用 ,远高于对照 (P<0 .0 5 ) ,而且随 DC数量的增加刺激 T细胞增生的活性越强。2例患者(M2 a1例 ,M31例 )的 BMMNC未转化为 DC,免疫表型分析显示 CD83及 CDla的表达较低 ,但 CD86 及HL A- DR的表达明显增高。结论 :利用一定组合的细胞因子可以将 AML细胞在体外转化为形态、表型和功能符合 DC特征的细胞。某些 AML患者的原始细胞不能转化为 DC,与其亚型无关 ,原因有待进一步探讨     

慢性髓性白血病来源的树突状细胞诱导的CTL体外作用研究

 目的　研究慢性髓性白血病来源的树突状细胞的免疫功能。方法　分离慢性期CML患者外周血单个核细胞 (PBMNC) ,用细胞因子GM CSF及IL 4在体外诱导培养DC ,检测细胞表型 ,并观察其诱导的CTL体外抗肿瘤效应。用酶联免疫 (ELISA)方法测定CML DC混合淋巴细胞反应 (MLR)上清液中IL 12及IFN γ的量 ,并与正常DC进行比较。结果　联合GM CSF及IL 4可诱导CML细胞分化为CML DC ,CML DC的CD1a、CD80、CD83表达率均低于正常DC ;CML DC混合淋巴细胞反应上清IL 12及IFN γ含量均低于正常DC ;CML DC能诱导出对自身CML细胞有特异性杀伤作用的CTL。结论　CML DC具有抗原提呈细胞的免疫功能 ,能诱导抗白血病CTL反应。     

The efficient generation of CD83 positive immunocompetent dendritic cells from CD14 positive acute myelomonocytic or monocytic leukemia cells in vitro

The ability of leukemic cells to differentiate to mature dendritic cells (DCs) was investigated in six acute myelomonocytic or monocytic leukemia cases. It was found that CD14 positive cells were more efficiently changed to CD83 positive mature typed DCs with granulocyte-macrophage colony-stimulating factor (GM-CSF)/interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha) compared with CD14 negative cells. Such leukemia derived DCs expressed a sufficient level of costimulatory molecules (CD80 and CD86), and were shown to be monoclonal based on an the X-inactivation analysis. They also stimulated not only allo- but auto-T lymphocytes, which thereafter became cytotoxic T lymphocytes (CTLs).     

Presentation of tumor antigens by phagocytic dendritic cell clusters generated from human CD34+ hematopoietic progenitor cells: induction of autologous cytotoxic T lymphocytes against leukemic cells in acute myelogenous leukemia patients

The use of antigen-presenting dendritic cells (DCs) is currently proposed for tumor immunotherapy through generation of CTLs to tumor antigens in cancer patients. In this study, DCs were differentiated using granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha from CD34+ hematopoietic progenitor cells that had been mobilized into the peripheral blood. To use the phagocytic activity of DCs for processing and presentation of tumor antigens, we established DC clusters containing immature DCs by preserving proliferating cell clusters without mechanical disruption. After an 11-day culture, the developed clusters contained not only typical mature DCs but also immature DCs that showed active phagocytosis of latex particles, suggesting that the clusters consisted of DCs of different maturational stages. These heterogeneous clusters could present an exogenous protein antigen, keyhold limpet hemocyanin, to both CD4+ and CD8+ T lymphocytes. Furthermore, in three acute myelogeneous leukemia patients, clusters pulsed with autologous irradiated leukemic cells could also induce antileukemic CTLs. The mechanical disruption of clusters abrogated the induction of CTLs to leukemic cells as well as to hemocyanin. This observation gives an important information for the use of heterogeneous DC clusters derived from autologous peripheral blood CD34+ cells in the case of immunotherapy for leukemia.     

Single-cell cloning of human, donor-derived antileukemia T-cell lines for in vitro separation of graft-versus-leukemia effect from graft-versus-host reaction

In previous studies, we showed the possibility of expanding in vitro polyclonal CTL lines directed against patient leukemia cells using effector cells derived from both HLA-matched and HLA-mismatched hematopoietic stem cell donors. Some CTL lines, especially those derived from an HLA-disparate donor, displayed residual alloreactivity against patient nonmalignant cells. In this study, we evaluated the possibility of separating in vitro CTLs with selective graft-versus-leukemia (GVL) activity from those potentially involved in the development of graft-versus-host disease (GVHD) through single T-cell cloning of antileukemia polyclonal CTL lines. We showed that CTLs that were expanded from a single T-cell clone (TCC), able to selectively kill leukemia blasts and devoid of alloreactivity towards nonmalignant cells, can be obtained from antileukemia alloreactive polyclonal CTL lines. TCCs expressed a wide repertoire of different T-cell receptor (TCR)-Vbeta families, mainly produced IFNgamma and interleukin 2, irrespective of CD8 or CD4 phenotype, and could be extensively expanded in vitro without losing their peculiar functional features. The feasibility of our approach for in vitro separation of GVL from GVH reaction opens perspectives for using TCCs, which are selectively reactive towards leukemia blasts, for antileukemia adoptive immune therapy approaches after hematopoietic stem cell transplantation, in particular from HLA-mismatched donors.     

Use and specificity of breast cancer antigen/milk protein BA46 for generating anti-self-cytotoxic T lymphocytes by recombinant adeno-associated virus-based gene loading of dendritic cells

Antigen-targeted immunotherapy is an emerging treatment for breast cancer. However, useful breast cancer antigens are only found in a subset of cancer patients. BA46, also known as lactadherin, is a membrane-associated glycoprotein that is expressed in most breast cancer cells but not in general hematopoietic cell populations. Moreover, it is much more difficult to generate CTLs against self-antigens. We wished to determine if the use of recombinant adeno-associated virus (rAAV) type 2 vectors for gene-loading of dendritic cells (DCs) could generate rapid, effective cytotoxic T lymphocytes (CTLs) against BA46. We were able to demonstrate that AAV/BA46/Neo-loading of DCs resulted in: (1) BA46 expression in DCs, (2) chromosomal integration of the AAV/BA46/Neo vector within DCs, (3) strong, rapid BA46-specific, MHC class I-restricted CTLs in only 1 week, (4) T-cell populations with significant interferon-gamma (IFN-gamma) expression but low IL-4 expression, (5) high CD80 and CD86 expression in DCs, and (6) high CD8:CD4 and CD8:CD56 T cell ratios. These data suggest that rAAV-loading of DCs may be useful for immunotherapeutic protocols against self-antigens in addition to viral antigens and that the BA46 antigen is potentially appropriate for cell-mediated immunotherapeutic protocols addressing ductal breast cancer.     

Generation of tumor-specific T-lymphocytes by cross-priming with human dendritic cells ingesting apoptotic tumor cells

It has been suggested that dendritic cells (DCs) are capable of ingesting apoptotic tumor cells (ATCs) and presenting tumor-associated antigens to immune cells. We evaluated the potential of human DCs, which have ingested ATCs, to serve as a source of antigenic epitopes for presentation to T cells specific for PCI-13, a squamous cell carcinoma of the head and neck cell line. Immature DCs (DCimm) generated in the presence of interleukin 4 and granulocyte machrophage colony-stimulating factor from peripheral blood monocytes of HLA-A2+ healthy donors were incubated in the presence of ATCs. Uptake of ATCs by DCs was monitored by flow cytometry and confocal microscopy after 2-18 h of coincubation. When DCs were matured (DCmat) in the presence of proinflammatory cytokines, their capacity to uptake ATCs was reduced. Responses of PCI-13-specific CD8+ T cells to unmodified PCI-13 cells and to DCimm or DCmat +/- ATCs or +/- tumor lysates were tested in gamma-IFN enzyme-linked immunospot and cytotoxicity assays. Unmodified tumor cells were found to be the best stimulators of antitumor activity of the established T-cell line, and ATCs alone were minimally stimulatory. However, DCs that ingested ATCs were able to present tumor antigens to CTLs, and DCimm and DCmat were almost equally stimulatory. When DCs plus various tumor-derived preparations were used as antigen-presenting cells with autologous HLA-A2+ T cells obtained from normal donors, DCs that had ingested ATCs were more effective in generating CD8+ CTLs than tumor cells alone or DCs pulsed with tumor lysates. The results indicate that human DCs fed with ATCs and then matured effectively generated T cell-mediated antitumor responses in vitro.     

Expression of CD 19 antigen on acute monoblastic leukemia cells at diagnosis and after TPA-induced differentiation

We have previously shown that CD 19, a B-lymphoid differentiation antigen, is expressed on acute myeloid leukemia cells. In this study, the expression of CD 19 and CD 14 (a monocytic antigen) was investigated in 18 cases of acute monoblastic leukemia. The staining by anti-CD 19 antibody (SB4) ranged between 26 and 81% of the cells, and was significantly correlated with the staining by anti-CD 14. Double stainings confirmed that the antigens were expressed on the same cells. After a 48-hr culture in the presence of TPA, most cells became adherent and lost CD 19 antigen, whereas CD 14 was still expressed with only minimal changes. It is concluded that CD 19 antigen is expressed on more immature stages of monoblastic leukemias. The hypothesis that CD 19 could be an early monocytic differentiation antigen is discussed.     

Tumor necrosis factor alpha down-regulates c-myc mRNA expression and induces in vitro monocytic differentiation in fresh blast cells from patients with acute myeloblastic leukemia

We have studied tumor necrosis factor alpha (TNF-alpha) for its capacity to induce differentiation and to modulate c-myc and c-fms protooncogene mRNA expression in fresh blasts from 10 patients with acute myeloblastic leukemia (AML). Bone marrow blast cells were grown in suspension cultures in the presence of 500 U/ml (62 ng/ml) of TNF-alpha for 7 days. Induction of differentiation was assessed by means of morphology, cytochemistry, immunophenotyping (CD11b, CD13, CD14, CD33), and nitroblue tetrazolium reduction. In all cases, exposure of leukemic blasts to TNF-alpha resulted in phenotypic changes consistent with induction of differentiation, although a marked variability in degree and type of response was observed. The majority of cases developed monocytic morphology and showed significant increases (chi 2 test, p less than 0.05) in phagocytic activity and/or expression of ANAE and myelomonocytic differentiation antigens (CD11b, CD14). TNF-alpha reduced c-myc mRNA level over a period of 24 hr in four of six cases studied: the two cases with no down-regulation were the least responsive in terms of myelomonocytic differentiation. These results confirm those obtained with leukemic cell lines, suggesting that TNF-alpha can induce differentiation of fresh AML blasts, mainly toward the monocytic lineage, and that induction of differentiation seems to be closely linked to down-regulation of c-myc mRNA expression over the first 24 hr rather than to attenuation of cellular proliferation per se.     

In vitro analysis of the antileukemic effect of tumor necrosis factor-alpha gene therapy with myeloid progenitor cells: the role of dendritic cells

We have previously demonstrated that tumor necrosis factor-alpha (TNF-alpha) gene therapy with transgene-expressing myeloid progenitor cells (32DTNF-alpha) is effective in inhibiting the progression of leukemia with a lethal dose of murine 32Dp210 myeloid leukemia cells. Because TNF-alpha has been shown to induce the activation and maturation of dendritic cells (DCs), we investigated the effect of TNF-alpha secreted by transduced cells (32DTNF-alpha cells) on the activation of DCs and their role in the production of antileukemic cytotoxic T lymphocytes (CTLs). We demonstrate that administration of 32DTNF-alpha cells to the mice enhances the allo-stimulatory capacity of the splenic (CD11c+) and bone marrow-derived DCs in both mixed leukocyte response and CTL development. The enhanced allo-stimulatory capacity of splenic DCs from mice injected with 32DTNF-alpha cells correlated with increase in the cell-surface expression of the costimulatory molecules CD40, CD80, CD86, and major histocompatibility complex (MHC) class II molecules (I-Ak), and production of interleukin-12 (IL-12). Furthermore, administration of 32DTNF-alpha cells during immunization with irradiated 32Dp210 leukemia cells augmented the capacity of splenic DCs to stimulate antileukemic CTL response in spleen cells. Collectively, these data suggest that in vivo production of TNF-alpha by transduced cells enhances the phenotypic and functional activation of DCs, resulting in induction of a stronger antileukemic cytotoxic T-cell immune response.     

Wogonin induces the granulocytic differentiation of human NB4 promyelocytic leukemia cells and up-regulates phospholipid scramblase 1 gene expression

Previous studies have firmly demonstrated that wogonin, a naturally occurring monoflavonoid extracted from the root of the Chinese herb medicine Scutellaria baicalensis , could effectively inhibit the proliferation of several cancer cell lines. However, little is known about the effect of wogonin on differentiation induction of leukemic cells. Here we investigate the potential role of wogonin in the proliferation and differentiation of NB4, a human promyelocytic leukemia cell line derived from a patient with acute promyelocytic leukemia. Our results indicated that wogonin significantly suppressed the proliferation and efficiently induced the differentiation of NB4 cells. NB4 cell growth was inhibited by 55–60% after treatment with 50 µM wogonin for a period of 5 days. The results of the nitroblue tetrazolium (NBT) reduction test (with 67.13% positive cells by 50 µM wogonin for 5 days), Giemsa staining (with 67.24% positive cells by 50 µM wogonin for 5 days), and the expression of mature-related cell-surface differentiation antigens CD11b and CD14 (with 70.94% CD11b⁺ and 5.82% CD14⁺ cells by 50 µM wogonin for 5 days) demonstrated an increase in the differentiation-inducing action of wogonin on the NB4 cells, which was accompanied by an increase in mRNA and protein expression of phospholipids scramblase 1 (PLSCR1). Meanwhile, the level of phosphorylated PKCδ (Ser643) was dramatically increased in wogonin treated NB4 cells. Interestingly, wogonin treatment displayed little effect on the apoptosis of NB4 cells. Taken together, the results reported here demonstrated that wogonin could promote the granulocytic differentiation of NB4 cells by up-regulating the expression of PLSCR1 gene. ( Cancer Sci 2008; 99: 689–695)