自身免疫性血小板减少性紫癜相关抗体的研究

目的　探索对自身免疫性血小板减少性紫癜 (AITP)诊断特异和敏感的实验方法。方法　采用单克隆抗体特异性俘获血小板抗原技术 (MAIPA技术 )并加以改进 ,对比检测血小板洗脱液和血浆中血小板膜糖蛋白特异性抗体。结果　AITP患者血浆游离抗血小板膜糖蛋白 (GPⅡb Ⅲa、GPⅠb Ⅸ )抗体总阳性率为 38.89%(5 4例中 2 1例 ) ,洗脱血小板表面抗血小板膜糖蛋白 (GPⅡb Ⅲa、GPⅠb Ⅸ )抗体总阳性率为 6 8.5 2 %(5 4例中 37例 ) ,两者差异有显著性 (校正 χ2 =19.39,P <0 .0 0 5 )。原发AITP组血浆游离及洗脱血小板表面抗血小板糖蛋白 (GPⅡb Ⅲa、GPⅠb Ⅸ )特异性抗体总阳性率与继发性AITP组比较差异无显著性。AITP患者血小板数量与自身抗体滴度呈明显负相关。结论　MAIPA法检测血小板洗脱液中抗血小板糖蛋白抗体在AITP的诊断和治疗中具有高度特异性 ,且敏感性较血浆抗体检测显著提高。     

自身免疫性血小、板减少性紫癜的特异性免疫学诊断的研究

目的 检测自身免疫性血小板减少性紫癜（AITP）患者及非免疫性血小板减少症患者的抗血小板特异性抗体,并与血小板相关抗体（PAIgG)相比较,评价其诊断及鉴别诊断价值。方法 用酶联免疫吸附竞争法检测PAIgG,改良单克隆抗体特异性俘获血小板抗原（MAIPA）技术检测抗血小板GPⅡb/Ⅲa、GPIb/Ⅸ的特异性抗体。结果 血小板特异性抗体较PAIgG的敏感性低,但特异性明显增强。结论 抗血小板特异性抗体对鉴别免疫性与非免疫性血小板减少具有重要临床意义。     

直接MAIPA对免疫性和非免疫性血小板减少性紫癜的鉴别诊断

目的检测免疫性与非免疫性血小板减少患者血小板膜糖蛋白特异性自身抗体，评价该方法在免疫性和非免疫性血小板减少性紫癜鉴别诊断中的价值。方法应用改良直接单克隆抗体俘获血小板抗原技术(MAIPA)检测血小板膜糖蛋白(GPⅡh／Ⅲa、GP I b和GPI a／Ⅱa)特异性自身抗体。结果免疫性血小板减少患者自身抗体阳性率(76．4％)显著高于非免疫性血小板减少患者(3．6％)(P＜0．05)。直接MAIPA诊断免疫性血小板减少的敏感性为76．4％，特异性为96．4％，阳性预测值为97．1％。GPⅡh／Ⅲa特异性自身抗体阳性的免疫性血小板减少患者血小板计数与自身抗体吸光度比值呈显著负相关(r=-0．338，P＜0．05)。结论直接MAIPA检测血小板膜糖蛋白特异性自身抗体对于鉴别免疫性与非免疫性血小板减少有一定意义。     

特发性血小板减少性紫癜患者脾脏CD5+和CD5-B细胞共同参与血小板自身抗体的产生

目的：研究慢性特发性血小板减少性紫癜（ITP）患者脾脏CD5^ B细胞水平的变化及CD5^ 和CD5^-B细胞与血小板膜糖蛋白（GP）特异性自身抗体产生的关系，以识别致病B细胞亚群。方法：应用双色流式细胞仪检测8例慢性ITP患者脾脏CD5^ B细胞水平。选择4例血浆抗GPⅡb/Ⅲa和抗GP Ⅰb/Ⅸ抗体双阳性ITP切脾患者，应用Ficoll密度梯度离心及花环形成分离法分离脾脏B淋巴细胞，继而采用镝产珠分选法分选、纯化CD5^ B细胞和CD5^-B细胞，并分别进行体外培养，应用改良MAIPA法检测血浆和细胞培养上清液的血小板特异性抗体。结果：ITP患者脾脏CD5^ B细胞水平圈晨自身免疫性疾病患者略有增高，二者之间差异无统计学意义。CD5^ B细胞水平与患者血小板计数无相关性。4例血浆抗GPⅡb/Ⅲa抗体和抗GPⅠb/Ⅸ抗体双阳性。另外1例CD5^ B细胞培养液抗GPⅡb/Ⅲa抗体阴性，抗GPⅠb/Ⅸ抗体阳性;CD5^-B细胞培养液抗GPⅡb/Ⅲa抗体和抗GPⅠb/Ⅸ抗体双阳性。结论：脾脏CD5^ 和CD5^-B细胞 均可产生血小板GP特异性自身抗体，抗体产生种类和滴度无明显差异。提示二者共同参与了ITP的发病过程。     

自身免疫性血小板减少性紫癜中的细胞免疫机制

自身免疫性血小板减少性紫癜(AITP)的细胞免疫病理生理机制首次综述是在十年前。但那时针对自身血小板抗原的自身IgG抗体的产生机制很少有研究,直到1995年,一些研究小组提出T细胞异常可能是慢性AITP自身抗体产生的原因。随后越来越多的证据指出AITP中存在自体反应T细胞,促使B细胞分化并分泌抗血小板自身IgG抗体。 正常免疫与自身免疫 对外来抗原的体液免疫反应是由多种类型细胞及其分泌产物构成的复杂的生物学反应。首先抗原如细胞表面糖蛋白等与抗原递呈细胞(APC)作用。APC主要指MHC-Ⅱ+巨噬细胞、     

血小板抗体及淋巴细胞亚群检测在特发性血小板减少性紫癜中的诊断意义

目的 比较抗血小板特异性抗体、PAIgG及淋巴细胞亚群在特发性血小板减少性紫癜（ITP）及非免疫性血小板减少症中的水平,以评价其在ITP中的诊断价值.方法 用改良单克隆抗体特异性俘获血小板抗原法（MAIPA）检测患者血浆中抗血小板膜糖蛋白（GPⅡb/Ⅲa、GPⅠb和P-选择素）的特异性抗体.利用流式细胞术（FCM）检测患者外周血中PAIgG及淋巴细胞亚群.结果 ITP组MAIPA的阳性率为63.3%,非免疫性血小板减少组为阴性;PAIgG分别为73.3%、45%.淋巴细胞亚群中,ITP组CD3、CD4、CD4/CD8显著高于正常对照组,CD8、CD19则显著低于正常对照组.结论 抗血小板特异性自身抗体抗体对提高ITP的诊断有一定的实用价值,淋巴细胞亚群的变化能较好地反映ITP 的病理机制.     

血小板特异性自身抗体检测在特发性血小板减少性紫癜中的意义

目的 检测特发性血小板减少性紫癜(ITP)患者体内的血小板特异性自身抗体与临床严重程度和临床疗效间的关系. 方法 应用改良的单克隆抗体特异性俘获血小板抗原(MAIPA)法检测血小板膜糖蛋白(GPⅡ bⅢa、GPIb)特异性自身抗体. 结果 ITP组(40例),10例为单一抗GPⅡ b Ⅲa抗体阳性.6例为单一抗GPIbα抗体阳性,20例为双抗体阳性,4例为双抗体阴性.非免疫性血小板减少组与正常对照组均为阴性.抗GPⅡbⅢa抗体(b=-0.071,P<0.01)、抗GPlbα抗体(b=-0.092,P<0.01)均与采血时血小板计数呈显著负相关.治疗后,双抗体阳性组8例治疗无效,单抗体阳性组(16例)1例治疗无效(χ2=6.09,P<0.05). 结论 血小板特异性自身抗体检测对鉴别特发性和非免疫性血小板减少症有一定价值.抗体种类与临床疗效有一定关系.     

流式免疫微球芯片技术分析特异性血小板自身抗体

目的建立流式免疫微球芯片技术（FCIBA）分析特异性血小板自身抗体的新方法。方法使用不同红色荧光强度的微球，包被不同血小板膜蛋白单克隆抗体（抗GPⅡb／Ⅲa、抗GPⅠa／Ⅱa、抗GPⅣ、抗GPⅠb／Ⅸ和抗HLA-ABC单克隆抗体），制备特异性血小板自身抗体检测微球，用流式细胞仪检测微球捕获的血小板抗原-自身抗体复合物，检测结果与微孔板改进抗原捕获ELISA（MACE）进行比较，并检测了部分免疫性以及非免疫性血小板减少性紫癜患者血清中的5种特异性血小板自身抗体。结果FCIBA分析抗GPⅡb／Ⅲa、抗GPⅠa／Ⅱa、抗GPⅣ、抗GPⅠb／Ⅸ和抗HLA-ABC5种特异性血小板自身抗体，批内重复性变异系数（CV）分别为4．82％、6．09％、5．04％、5．73％、5．30％；稀释试验呈对数线性相关，相关系数（r）分别为0．9972．0．9966．0．9988．0．9965、0．9982；新方法对5种特异性血小板自身抗体的分析结果均与MACE试验结果高度相关，r值分别为0．9289、0．9224、0．8894、0．9100、0．9134（P均〈0．01）。新方法分析98例免疫性血小板减少性紫癜患者的血清样本，血小板特异性自身抗体检出的阳性率为51．69％；其中，抗GPⅡb／Ⅲa为40．82％，抗GPⅠa／，Ⅱa为24．45％，抗GPⅣ为19．39％，抗GPⅠb／Ⅸ为32．65％，抗HLA-ABC为17．35％。新方法分析40例非免疫性血小板减少性紫癜患者的血清样本，阳性率为0。结论本研究建立了FCIBA分析特异性血小板自身抗体的新方法，可同时分析抗血小板GPⅡb／Ⅲa、GPⅠa／，Ⅱa、GPⅣ、GPⅠb／Ⅸ和HLA-ABC5种特异性血小板自身抗体。     

血小板特异性抗体对特发性血小板减少性紫癜诊断价值的研究

目的:检测特发性血小板减少性紫癜及非免疫性血小板减少症患者抗血小板特异性抗体与血小板相关抗体,评价其在特发性血小板减少性紫癜中的诊断价值。方法:用流式细胞仪检测血小板相关抗体PAIgG,PAIgA,PAIgM;用改良单克隆抗体特异性俘获血小板抗原技术检测抗血小板膜糖蛋白(GPⅡb/Ⅲa,GPⅠb/Ⅸ)特异性自身抗体。结果:血小板相关抗体在特发性血小板减少性紫癜组敏感度为80%,在非免疫性血小板减少症组为63.3%。改良单克隆抗体特异性俘获血小板抗原法检测抗GPⅡb/Ⅲa和GPⅠb/Ⅸ抗体,在特发性血小板减少性紫癜组中的敏感度分别为53.3%和30%;在非免疫性血小板减少症组中除1例GPⅠb/Ⅸ阳性外,其余均为阴性;2组检出率比较差异有统计学意义(P<0.05)。结论:血小板相关抗体敏感度较高,但特异度较低;抗血小板特异性抗体敏感度虽较低,但特异性较高,可鉴别特发性血小板减少性紫癜和非免疫性血小板减少症。可作为特发性血小板减少性紫癜的特异性诊断指标。     

特发性血小板减少性紫癜患者IgG酶切片段F(ab'')2的免疫活性及其对血小板聚集功能的影响

目的制备特发性血小板减少性紫癜（ITP）患者血浆IgG及其酶切片段，探讨其与血小板GPⅡb／Ⅲa和（或）GPⅠb／Ⅸ结合的免疫活性及其对正常人血小板聚集功能的影响。方法用改良MAIPA法和比浊法血小板聚集试验筛选出自身抗体阳性并且能抑制血小板聚集的患者，用蛋白A柱纯化其血浆IgG抗体并用胃蛋白酶制备F（ab’）2片段，改良单克隆抗体俘获血小板抗原技术（MAIPA）检测完整抗体及其酶切片段与血小板膜糖蛋白的结合活性；比浊法血小板聚集试验对比观察ITP患者血浆、纯化的IgG抗体及其酶切片段对正常人血小板聚集功能的影响。结果①68例慢性ITP患者中，34例（53．6％）血浆中抗GPⅡb／Ⅲa和（或）GPⅠb／Ⅸ自身抗体阳性，其中5例（14．7％）明显抑制了二磷酸腺苷（ADP）或瑞斯托霉素对血小板聚集的诱导作用；②用蛋白A柱结合蛋白酶酶切成功获得了纯化的IgG及F（ab’）2片段；③患者纯化的IgG及F（ab’）2片段均具有抗GPⅡb／Ⅲg或GPⅠb／Ⅸ活性，但去除IgG的血浆丧失了与GPⅡb／Ⅲa或GPⅠb／Ⅸ的结合活性；④2例患者纯化的IgG及其F（ab＇）2片段抑制ADP诱导的血小板聚集。结论F（ab’）2片段是IgG自身抗体的功能片段，它不但保留了良好的抗原结合活性并可抑制血小板聚集功能，其抑制聚集作用呈剂量依赖性。     

流式微球技术检测糖蛋白Ⅱb/Ⅲ a自身抗体在特发性血小板减少性紫癜诊断中的应用

目的 建立流式微球技术检测血小板膜表面糖蛋白Ⅱ b/Ⅲa(GPⅡb/Ⅲa)特异性自身抗体的方法,比较该方法和改良间接单克隆抗体俘获血小板抗原技术(MAIPA)在特发性血小板减少性紫癜(ITP)与非免疫性血小板减少性紫癜鉴别诊断中的价值.方法 应用抗人血小板GPⅡb/Ⅲa单抗(CD41a)包被微球.分离血小板,将血小板裂解后与包被过的微球孵育,再加入PE标记的羊抗人IgG多克隆抗体,流式细胞术分析.分别用该方法和改良间接MAIPA检测血小板表面和血浆中的糖蛋白特异性自身抗体,并将检测结果进行比较.结果 将样本的平均荧光强度值(MFI)与正常对照MFI的均值比较,计算比率.该比率均值及范围在ITP组为3.36(0.84～22.94),非免疫性血小板减少组为1.16(0.67～5.59),正常对照组为1.08(0.72～1.76).非参数检验得ITP组荧光强度比率与非免疫性血小板减少组及正常对照组存在显著差异(P《0.01).若将正常对照组上限作为界值,比率大于1.76定为阳性,则流式微球技术诊断ITP的敏感性为71.43%,特异性为94.28%,阳性预测值为95.24%,其敏感性高于改良间接MAIPA的测定值(51.79%)(χx2=4.57，P<0.05)。由ROC曲线得流式微球法区分ITP患者与正常人的鉴别效度为0.916。结论 流式微球技术检测血小板膜表面糖蛋白特异性自身抗体，耗时短、重复性好，敏感性高于改良间接MAIPA，对提高ITP的实验诊断水平及指导临床治疗有一定的价值。     

Cellular immune mechanisms in autoimmune thrombocytopenic purpura: An update

Autoimmune thrombocytopenic purpura (AITP) is a bleeding disorder in which autoantibodies are directed against an individual's own platelets, leading to enhanced clearance through Fc receptor (R)-mediated phagocytosis by macrophages residing in the reticuloendothelial system (RES), particularly in the spleen. The production of IgG autoantibodies is critically dependent on cellular immune mechanisms particularly relating to T cells. We review the recent literature of the cell-mediated immunology of AITP focusing on platelet phenotype, genetics, T-cell reactivities, and cytokine profiles in patients with AITP. Understanding the interaction between these cell-mediated mechanisms is vital for developing antigen specific immunotherapies to treat this autoimmune disease.     

The cellular immunology associated with autoimmune thrombocytopenic purpura: an update.

Chronic autoimmune thrombocytopenic purpura (AITP) is an organ specific autoimmune bleeding disease in which autoantibodies are directed against the individual's own platelets, resulting in increased Fc-mediated platelet destruction by macrophages in the reticuloendothelial system. Although AITP is primarily mediated by IgG auto-antibodies, their production is regulated by the influence of T lymphocytes and antigen presenting cells (APC). This review argues that enhanced T helper cell/antigen presenting cell interactions in patients with AITP may be responsible for IgG anti-platelet auto-antibody production. Understanding these cellular immune responses in AITP may lead to the development of more immune specific therapies for the management of this disease.     

自身免疫性血小板减少性紫癜患者外周血中CD4+CD25+调节性T细胞、sFas和sFasL的表达及临床意义

本研究通过检测成人自身免疫性血小板减少性紫癜(AITP)外周血中CI4+CD25+调节性T细胞(Treg)、sFas和sFasL的表达,探讨它们在AITP发病机制中的作用及临床意义,为寻求AITP治疗的有效方法提供理论依据.采用流式细胞术分别检测30例AITP患者和18例正常对照者外周血CD4+T、Treg、CD4+ CD25-T细胞表达率及Treg/CD4+T比值;用酶联免疫吸附法(ELISA)检测AITP患者治疗前后及对照组外周血sFas、sFasL表达水平.结果表明,AITP组外周血中CD4+T细胞表达率低于对照组(p＜0.05),Treg细胞表达率及Treg/CD4+T比值明显低于正常对照组(p＜0.0l).AITP组患者治疗前外周血中sFas和sFasL水平明显高于治疗后和正常对照组(p＜0.01),AITP组治疗后与正常对照组外周血sFas、sFasL水平差异无统计学意义(p＞0.05).AITP患者治疗前Treg细胞表达率、Treg/CD4+T细胞比值与血小板计数呈正相关;AITP患者外周血中sFas和sFasL水平呈正相关;CD4+T细胞、CD4+CD25 -T细胞表达率,sFas、sFasL浓度与血小板计数无明显相关;Treg细胞表达率和sFas、sFasL浓度间没有明显相关性.结论:Treg在AITP的发病机制中发挥一定作用;Treg细胞水平与AITP病情的严重程度有关;sFas和sFasL水平异常参与了AITP的免疫病理过程.     

T cell and cytokine abnormalities in patients with autoimmune thrombocytopenic purpura.

Autoimmune thrombocytopenic purpura (AITP) is a bleeding disorder in which autoantibodies are directed against an individual's own platelets, leading to enhanced clearance through Fc receptor (R)-mediated phagocytosis by macrophages residing in the reticuloendothelial system, particularly in the spleen. Although the immunopathogenesis of the disease is autoantibody-mediated, there is now substantial evidence that suggest that the antiplatelet autoantibodies are under the control of T helper (Th) cells and the cytokines that they produce. This review will summarize the recent literature regarding abnormal Th cell reactivities and cytokine secretion in AITP. Reviews of the earlier literature regarding cell mediated immunity in chronic AITP have been published [; ]. Understanding the immune mechanisms controlling cell-mediated mechanisms is vital for developing antigen specific immunotherapies to treat the disease.     

Platelet transfusion refractoriness associated with HPA-1a (Pl(A1)) alloantibody without coexistent HLA antibodies successfully treated with antigen-negative platelet transfusions

BACKGROUND: Alloimmune-mediated refractoriness to platelet transfusion is most commonly due to antibody to HLA antigens in multiply transfused or multiparous patients. Published reports of poor transfusion response due to antibodies to platelet-specific antigens are rare and often confounded by the presence of coexistent antibodies against HLA antigens. CASE REPORT: A case is presented of a multiparous woman with acute myelogenous leukemia whose sole cause of transfusion refractoriness was antibody to platelet antigen HPA-1a. She responded dramatically to HPA-1a-negative platelet transfusion. CONCLUSION: This case provides strong serologic and clinical evidence that platelet transfusion refractoriness may result from antibodies to platelet-specific antigens.     

流式微球技术检测血小板特异性抗体

目的建立流式微球技术检测血小板特异性自身抗体方法,并对方法学及临床应用进行初步探讨。方法用包被抗血小板膜糖蛋白(GP)Ⅰb、Ⅱb、Ⅲa、Ⅱb/Ⅲa单克隆抗体的微球捕获与血小板GP结合的特异性抗体,加入FITC标记的羊抗人IgG抗体后用流式细胞仪检测分析。结果特发性血小板减少性紫癜(ITP)组4种单抗荧光强度比值与非ITP血小板减少组和正常对照组有显著性差异(P<0.01);若将ITP组患者4种单抗荧光强度比值分别大于正常对照组上限1.37、1.24、1.48和1.19判断为阳性,则流式微球技术检测血小板特异性自身抗体的敏感性为73.2%,特异性为94.3%;4种单抗联合检测总体敏感性明显高于改良间接单抗特异的血小板抗原固定试验(MAIPA)(P<0.05),且大于各单个抗体检测敏感性。结论流式微球技术可以简便、快捷地检测血小板膜糖蛋白特异性抗体,联合检测多种自身抗体可以提高检测阳性率,对于ITP的诊治具有一定的临床价值。     

Platelet-specific antibodies in HLA-immunized patients receiving chronic platelet support

BACKGROUND: In HLA-alloimmunized patients, the unexpected failure of HLA-matched platelet transfusions usually raises the suspicion about concomitant platelet-specific antibodies. As the reported frequency of platelet-specific antibodies in multitransfused patients varies widely, the aim of this study was to determine the prevalence of such antibodies in a population of chronic thrombocytopenic patients with HLA antibodies. STUDY DESIGN AND METHODS: From 1985 to 1997, 11,777 determinations of HLA antibodies were performed in 1330 hematologic patients receiving chronic platelet support. Fifty-two patients with HLA alloimmunization that lasted more than 1 month were selected. The search for platelet-specific antibodies was performed by using a monoclonal antibody immobilization of platelet antigens assay, thus allowing the identification of platelet-specific antibodies directed against the platelet glycoproteins (GP) Ib/IX, GPIIb/IIIa, and GPIa/IIa. Specificity of the platelet-specific antibodies was further investigated by using a solid-phase assay with chloroquine-treated platelets. RESULTS: Only 2 (3.8%) of the 52 patients had platelet-specific antibodies. One antibody reacted with an epitope of the GPIIb/IIIa that was present in all the panel platelets, and that probably was an autoantibody. The other was an anti-HPA-5b. CONCLUSIONS: The prevalence of platelet-specific antibodies in patients with HLA alloimmunization is very small. The search for concomitant platelet-specific antibodies would be indicated only when other causes of refractoriness to HLA-matched platelets are ruled out.