Chronic isolated macrothrombocytopenia with autosomal dominant transmission: a morphological and qualitative platelet disorder

Abstract: We studied 47 subjects belonging to 13 unrelated families with a history of mild haemorrhagic diathesis and chronic thrombocytopenia. 36 patients presented some degree of thrombocytopenia: 7/36 (19%) had slight thrombocytopenia (100–150×10⁹/L); 26/36 (72%) had mild thrombocytopenia (50–100×10⁹/L) and 3/36 (8%) had severe thrombocytopenia (<50×10⁹/L). No correlation was observed between platelet count and the degree of haemorrhagic diathesis, which was mild in the majority of patients. Transmission was autosomal dominant. Platelet anisocytosis, increased percentage of large platelets and absence of leukocyte inclusions were observed in 26/30 (87%) of the examined blood smears. The ultrastructural appearance of platelets was normal. Megakaryocytes appeared normal in number in 10/10 patients, but showed asynchronous nuclear-cytoplasm maturation and mainly nonlobulated nuclei. Platelet aggregation was studied in 26 patients and either increased or decreased curves were variably observed in response to different aggregating agents. Platelet-associated IgG (PAIgG) was increased in 18/31 (58%) patients, while serum autoantibodies against platelet glycoproteins Ib/IX or IIb/IIIa were demonstrable in only 1 case. An increased expression of platelet surface glycoproteins Ib and IIb/IIIa, as studied by murine monoclonal antibodies binding in 17 cases, was observed. Platelet survival performed by 111In-oxine-labelled autologous platelets was normal in the 3 studied patients. Congenital macrothrombocytopenia confirms to be a distinct clinical disorder for which the name of “chronic isolated hereditary macrothrombocytopenia” is proposed.     

Specific cross-reaction of anti-dsDNA antibody with platelet integrin GPIIIa49-66

Anti-platelet autoantibodies are frequently found in systemic lupus erythematosus (SLE) patients and contribute to the development of SLE-associated immunologic thrombocytopenia (SLE-ITP). Although the correlation of anti-dsDNA autoantibody with platelet-associated antibody has been reported, the potential mechanism underlying such a correlation is incompletely understood. We have reported that anti-platelet integrin GPIIIa49-66 (CAPESIEFPVSEARVLED) autoantibodies play a major role in the development of HIV-1-related thrombocytopenia (HIV-1-ITP). The strong negative charge of GPIIIa49-66 prompts us to investigate whether GPIIIa49-66 can be an epitope mimicking dsDNA. We report here that anti-GPIIIa49-66 antibodies are found in three out of nine SLE-ITP patients. Double-stranded (ds) DNA competitively inhibited the binding of purified patient anti-dsDNA antibodies to GPIIIa49-66 peptide. Both polyclonal and monoclonal anti-GPIIIa49-66 antibodies are able to cross-react with dsDNA. Consistent with previous reports, the DNA binding activities of anti-GPIIIa49-66 antibodies are mainly dependent on the positively charged amino acid in the heavy-chain complementarity-determining region 3 (HCDR3). The HCDR3 of human SLE anti-dsDNA monoclonal antibody (mAb) 412.67 demonstrates a similar positively charged amino acid chain orientation compared with that of anti-GPIIIa49-66 mAb A11, and it cross-reacts with GPIIIa49-66 peptide. Purified anti-GPIIIa49-66 antibodies from SLE-ITP patients are able to induce platelet fragmentation in vitro and to induce thrombocytopenia in vivo. Thus, our data suggest that specific epitope cross-reaction between GPIIIa49-66 and dsDNA could be a mechanism involved in the development of SLE-associated thrombocytopenia.     

急性白血病患者血小板免疫状态的变化

目的 :探讨急性白血病患者出血与血小板相关抗体 (PAIgG)和抗血小板糖蛋白Ⅱb/Ⅲa (抗GPⅡb/Ⅲa)自身抗体的关系。方法 :用酶联免疫吸附法测定 60例急性白血病 (AL)患者和 2 0例正常对照的PAIgG和抗GPⅡb/Ⅲa自身抗体。其中抗GPⅡb/Ⅲa自身抗体用SZ 2 1 (针对GPⅢa)和SZ 2 2 (针对GPⅡb)两种单抗同时测定。并同时测定了血小板计数 (BPC)和血小板聚集功能 (PagT)等。结果 :AL组PAIgG值 ((1 54 .30± 2 5 .71 )fg/plt)显著高于正常对照组 ((2 .0 8± 1 .72 )fg/plt) ,P <0 .0 1。 60例AL中 40例在正常参考值 (5 .8fg/plt)以上。其中 2 4例外周血血小板减少 ,且PAIgG值与血小板数呈负相关 (P <0 .0 0 1 ,r=- 0 .395) ;1 6例血小板数正常。 60例AL中抗GPⅡb/Ⅲa自身抗体阳性率 40 % (2 4 / 60 ) ,其中 1 4例单独SZ 2 1阳性 ,1 0例SZ 2 2阳性。 2 4例阳性患者均呈现ADP诱导的聚集功能减低 ,用 5μlADP诱聚时 ,最大聚集率 (5 .58± 4 .76) %。 结论 :部分AL患者存在血小板免疫异常所致的免疫性血小板减少和血小板质的异常     

ITP患儿血小板内cAMP的研究

本文用放免法测定了38例正常儿及47例 ITP 患儿血小板内 cAMP 值。发现无论急、慢性患儿血小板内 cAMP 值均显著增高,其增高与血小板功能呈负相关,与血小板计数无相关性。急性患儿 PAIgG 增高,血小板内 cAMP 亦增高,二者之间呈正相关,而慢性患儿则无此相关性。并对 cAMP 的增高与 ITP 的发病机制进行了阐述。     

特发性血小板减少性紫癜患者血小板相关抗体及网织血小板检测的临床意义

目的探讨血小板相关抗体(PAIgG)和网织血小板(RP)检测在特发性血小板减少性紫癜(ITP)治疗中的临床意义。方法收集常州市第一人民医院2003-06～2004-10住院的ITP患者48例,根据疗效分为两组,其中临床有效组40例,临床无效组8例,以50例健康人为正常对照。应用流式细胞仪(FCM)测定其治疗前后血浆和(或)血清PAIgG及RP%,并常规血小板计数。结果ITP患者临床有效组治疗后较治疗前血小板计数明显升高、PAIgG和RP%显著降低(P<0.01)。临床无效组治疗前后血小板计数、PAIgG和RP均无明显变化(P>0.05)。两组治疗前3项指标与对照组比较差异有显著性意义(P<0.01)。结论PAIgG和RP动态检测将是ITP患者血小板治疗效果的预测指标之一。     

Detection of platelet-associated IgG in chronic immune thrombocytopenic purpura using antibody-coated polyacrylamide beads

Summary Platelet-associated IgG (PAIgG) was detected by means of anti-human IgG coated polyacrylamide beads (Immunobeads) technique in 32 patients with chronic ITP. Both a direct test (with in vivo sensitized platelets) and an indirect test (with in vitro loaded platelets) were carried out. The percent of rosette forming beads was both in the direct test (41.2%) and in the indirect test (32.6%) significantly higher in the cases of chronic ITP patients than in the controls (2.5% and 3.2%, respectively). These results confirm the diagnostic value of this new, relatively simple and rapid method in routine clinical practice.     

Simultaneous measurements of megakaryocyte-associated IgG (MAIgG) and platelet-associated IgG (PAIgG) in chronic idiopathic thrombocytopenic purpura

Abstract: We have simultaneously measured platelet-associated IgG (PAIgG) and megakaryocyte-associated IgG (MAIgG) in 30 untreated patients with chronic idiopathic thrombocytopenic purpura (CITP). Megakaryocytes were purified from bone marrow by 35% Percoll gradient centrifugation, followed by negative immunopanning using magnetic immunobeads. The normal range of MAIgG in 30 healthy donors was 15.5 & 10.0 ng/10⁵ megakaryocytes, whereas MAIgG in the 30 CITP patients was 140 & 59.3 ng/10⁵ megakaryocytes, although the values were widely distributed. From the PAIgG and MAIgG data, CITP patients were classified into three types; type I (PAIgG < 200 ng/10⁷ platelets and MAIgG < 150 ng/10⁵ megakaryocytes), type II (PAIgG > 200 ng and MAIgG > 150 ng), and type III (PAIgG < 200 ng and MAIgG > 150 ng). Patients with types I and III had good clinical courses, but, in contrast, patients with type II responded poorly to steroid therapy followed by splenectomy or became refractory to treatment. In splenectomized patients, MAIgG of responder was promptly decreased to normal range and, in contrast, that of non-responder was persistently elevated. These results indicate that anti-platelet autoantibodies are able to bind with megakaryocytes in the bone marrow as well as with platelets in the peripheral blood, and the results also suggest that megakaryopoiesis in CITP is heterogeneous. Simultaneous measurement of PAIgG and MAIgG may predict the clinical outcome of CIPT.     

龙丹生血颗粒对免疫性血小板减少性紫癜模型小鼠外周血象与骨髓巨核细胞以及血清PAIgG水平的影响

目的 观察龙丹生血颗粒对ITP模型小鼠骨髓巨核细胞和血清PAIgG的影响.方法 70只Balb/c小鼠随机分为对照、模型、升血小板胶囊、泼尼松、龙丹生血颗粒大、中、小剂量7组,除正常组外,其余各组隔日1次腹腔注射豚鼠抗小鼠血小板血清（GP-APS）建立ITP小鼠模型,于造模第8天开始给药,各组均按0.2ml/（10g·d）体积灌胃.其中,正常组、模型组灌服生理盐水,升血小板胶囊组灌胃升血小板胶囊内容物混悬液1.125g/kg,泼尼松按0.0113mg/（10g·d）灌胃,龙丹生血颗粒大、中、小剂量组分别按13.75g生药/千克、6.88g生药/千克、3.44g生药/千克灌胃.连续8天后眼球取血分离血清,进行血液学、血清PAIgG检测,并观察小鼠骨髓巨核细胞形态及分类.结果 与正常组相比,模型组小鼠PLT、WBC、Hb降低,血清PAIgG明显升高,骨髓产板巨核细胞数减低.与模型组相比,龙丹生血颗粒各剂量组小鼠外周血PLT、WBC、Hb数值均有所恢复.大剂量组产板巨核细胞明显增加,PAIgG有所降低.结论 龙丹生血颗粒通过降低血清PAIgG水平、促进骨髓巨核细胞分化而提升ITP模型动物外周血小板数值.     

Severe thrombocytopenia suggesting immunological mechanisms in two cases of vivax malaria

Case 1: A 27-year-old woman, referred to our hospital because of relapsing fever after travel to Thailand, was given a diagnosis of vivax malaria. Clinical investigation revealed thrombocytopenia, elevated platelet-associated IgG (PAIgG), and negative antibody against Plasmodium vivax antigen. After antimalarial treatment, the levels of both the platelets and PAIgG returned to normal. Case 2: A 28-year-old Sri Lankan man was admitted to our hospital with a complaint of fever. The patient had thrombocytopenia, elevated PAIgG, and positive antibody against Plasmodium vivax antigen. He contracted malaria in Sri Lanka about 6 months prior to this admission. After treatment, the platelet count and PAIgG level returned to normal. In these two cases, high levels of PAIgG may have been involved in the development of the thrombocytopenia. In the first patient, in particular, the thrombocytopenia was thought to be induced by some immunological mechanism prior to the detection of antimaralial antibodies in serum. Am. J. Hematol. 56:183–186, 1997. © 1997 Wiley-Liss, Inc.     

血小板表面相关抗体检测对ITP的诊断作用研究

目的 研究血小板表面相关抗体检测对特发性血小板减少性紫癜(ITP)的诊断作用研究.方法 选取2012年1月至2013年1月收治的ITP患者50例(A组),非免疫性血小板减少患者20例(B组),其他自身免疫性疾病患者20例(C组),另征集20名健康志愿者作为D组.测定4组血小板膜糖蛋白Ⅱb-Ⅲa(PAC-1)以及血小板相关抗体PAIgG、PAIgA、PAIgM水平,对ITP患者进行病情分级,并对治疗后进行疗效评定,统计各个分级的ITP患者及不同疗效患者血小板相关抗体阳性率.结果 4组PLT、PAC-1、PAIgA、PAIgG、PAIgM水平差异有统计学意义(P＜0.05).A组PAIgA、PAIgG、PAIgM均明显高于其他3组患者(P＜0.05).ITP 1、2、3级患者PAIgA、PAIgG、PAIgM阳性率差异有统计学意义(P＜0.05).且随着ITP分级升高,患者PAIgA阳性率呈升高趋势(r值分别为0.712、0.614、0.732,P＜0.05).显效、进步、无效组患者PAIgA阳性率差异有统计学意义(P＜0.05),且随着治疗效果的改善,PAIgA阳性率呈降低趋势(r=0.642,P＜0.05).显效、进步、无效组患者PAIgG、PAIgM阳性率差异有统计学意义(P＜0.05).且随着疗效改善,患者PAIgG阳性率呈升高趋势(r值分别为0.723和0.721,P＜0.05).结论 ITP患者血小板表面相关抗体较正常人有所升高,且血小板相关抗体高低与病情程度有一定的相关性,有助于临床ITP的诊疗.