原发性免疫性血小板减少症血小板参数及功能的改变

原发性免疫性血小板减少症(primary immunethrombocytopenia,ITP)是儿童常见的因自身免疫功能紊乱导致血小板减少的出血性疾病,约占出血性疾病总数的30%[1],具有复杂的异质发病和临床出血表型不一的特点,目前对本病认识的主要发病机制是机体的细胞免疫和体液免疫异常导致血小板破坏增加和生成不足[2-3],颅内出血是本病死亡的主要原因。目前对本病的诊断尚无"金标准",骨髓穿刺具有创伤性,是否需要常规进行骨     

淋巴细胞凋亡与特发性血小板减少性紫癜研究进展

特发性血小减少性紫癜(idiopathic thrombocytopenic purpura,ITP)是一种儿童常见的由于血小板破坏增多的出血性自身免疫病。目前，虽然许多学者在体液免疫、细胞免疫、血小板功能及内分泌等多方面进行了深入的探讨，但该病的发病机制仍然未完全明了。年近来，由于分子生物学、分子免疫学、细胞生物学等技术的飞速发展，细胞调亡成为ITP发病机制     

特发性血小板减少性紫癜研究进展

特发性血小板减少性紫癜(idiopathic thrombocytopenic purpura,ITP)是儿童常见的出血性疾病,临床表现为皮肤、粘膜的自发性出血,实验室检查血小板数量减少,骨髓巨核细胞数量正常或增多,伴成熟障碍.目前ITP确切的发病机制尚不清楚,早期研究发现ITP的发生与自身抗体有关,进而又证实ITP存在细胞免疫功能的紊乱,近年来,有学者提出ITP患者血小板和巨核细胞也存在异常,提示ITP不仅表现为血小板数量减少,同时存在功能障碍,井且与免疫功能紊乱有一定关系.本文就近年来ITP血小板的相关研究进展作一综述.     

儿童难治性特发性血小板减少性紫癜的诊疗进展

特发性血小板减少性紫癜(idiopathic thrombocytopenic purpura,ITP)又称为免疫性血小板减少症,是临床最常见的获得性出血性疾病.以血小板减少、血清中出现抗血小板抗体、骨髓巨核细胞数增加或正常伴成熟障碍为特征.约70％患者在诊断后的6个月内痊愈,但仍有部分患者转为持续性、慢性甚至难治性ITP.ITP的发病机制仍不完全清楚,目前认为主要有遗传易患性、血小板破坏过多及生成不足.因此,新的免疫抑制剂及促血小板生成剂不断被应用于临床中.该文对近年来在难治性ITP的诊断标准、严重度分级和治疗等方面取得的进展作一综述.     

淋巴细胞凋亡与特发性血小板减少性紫癜研究进展

特发性血小减少性紫癜(idiopathic thrombocytopenic purpura,ITP)是一种儿童常见的由于血小板破坏增多的出血性自身免疫病.目前,虽然许多学者在体液免疫、细胞免疫、血小板功能及内分泌等多方面进行了深入的探讨,但该病的发病机制仍然未完全明了.年近来,由于分子生物学、分子免疫学、细胞生物学等技术的飞速发展,细胞调亡成为ITP发病机制研究的热点,关于细胞凋亡在特发性血小板减少性紫癜中的研究已取得许多新进展.     

幽门螺杆菌感染与儿童特发性血小板减少性紫癜

特发性血小板减少性紫癜(ITP)是以自身抗体介导的血小板破坏为特征的一组疾病,近年来许多研究显示部分成年人ITP的发生与幽门螺杆菌(Hp)感染密切相关,清除Hp后ITP患者的血小板数量有明显提高.研究认为Hp相关的ITP与抗原交叉反应有关,但其确切机制目前尚不明确;儿童ITP是否需要清除Hp治疗,国内外也存在争议.     

儿童慢性原发性免疫性血小板减少症

原发性免疫性血小板减少症(ITP)是一种自身免疫性疾病,在儿童中发病率约为(4～5)/10万,多数(80%～90%)ITP患儿在确诊后12个月内血小板数可恢复正常,但少数(10%～20%)患儿血小板减少会超过1年,成为慢性ITP。慢性ITP的发病机制尚未清楚,现有研究认为是在患儿易感基因背景下,由于感染和免疫紊乱产生的自身免疫抗体对单核-巨噬细胞系统的破坏造成血小板减少。文章综述慢性ITP的诊断,预测因素及相关治疗方法。     

幽门螺杆菌感染与儿童特发性血小板减少性紫癜

特发性血小板减少性紫癜(ITP)是以自身抗体介导的血小板破坏为特征的一组疾病,近年来许多研究显示部分成年人ITP的发生与幽门螺杆菌(Hp)感染密切相关,清除Hp后ITP患者的血小板数量有明显提高.研究认为Hp相关的ITP与抗原交叉反应有关,但其确切机制目前尚不明确;儿童ITP是否需要清除Hp治疗,国内外也存在争议.     

幽门螺杆菌感染与儿童特发性血小板减少性紫癜

特发性血小板减少性紫癜(ITP)是以自身抗体介导的血小板破坏为特征的一组疾病,近年来许多研究显示部分成年人ITP的发生与幽门螺杆菌(Hp)感染密切相关,清除Hp后ITP患者的血小板数量有明显提高.研究认为Hp相关的ITP与抗原交叉反应有关,但其确切机制目前尚不明确;儿童ITP是否需要清除Hp治疗,国内外也存在争议.     

特发性血小板减少性紫癜B淋巴细胞异常研究进展

现已证实特发性血小板减少性紫癜(ITP)是因免疫机制引起血小板破坏增加的临床综合征,又称免疫性血小板减少性紫癜。该病发病机制错综复杂,目前尚未明确。现就ITP患儿B淋巴细胞异常及可能的致病机制作一综述。     

Mechanisms in childhood idiopathic thrombocytopenic purpura (ITP)

The concepts of the pathological mechanisms in childhood idiopathic thrombocytopenic purpura (ITP) have, to a great extent, been based on clinical experience and on data generated in adults. Studies performed in children have demonstrated that platelet antigen-specific autoantibodies are present in chronic ITP and, to a lesser extent, in acute ITP. It is, however, likely that the mechanisms initiating the production of autoantibodies are different in the two entities. In acute ITP, production of autoantibodies and immune complexes is probably linked to a transient antiviral immune response. Chronic ITP in children is an autoimmune process which eventually is reversible in many cases. The initiating factors, as in other autoimmune disorders, are yet to be elucidated.     

Measurement of platelet antibodies: where do we stand?

The immune pathogenesis of idiopathic thrombocytopenic purpura (ITP) is well established; however, the diagnostic criteria do not require identification of platelet autoantibodies. The abundance of methods devised for the measurement of platelet antibodies over the years provides evidence of the so-far futile search for a reliable diagnostic assay. The latest generation of platelet antigen-specific assays has widened the knowledge of autoimmune mechanisms in thrombocytopenia, but they still lack sufficient sensitivity to be a useful tool in the routine evaluation of thrombocytopenic patients.     

Role of complement in immune or idiopathic thrombocytopenic purpura

The clinical course of immune or idiopathic thrombocytopenic purpura (ITP) is variable, suggesting different mechanisms for the decreased platelet count. The complement factors C3 and C4 have been detected on platelets, both alone and in association with immunoglobulin G (IgG), and a reduced platelet survival time has been described. Platelets have the capacity to interact with the complement system since they have both complement receptors and complement regulatory proteins on their cell membranes. The membrane attack complex (C5b-9) induced by antiplatelet antibodies generates platelet microparticles in a concentration-dependent manner. A marked variation in resistance to this phenomenon has been demonstrated between individuals and between men and women. These platelet microparticles seem to retain their biological role in haemostasis. Platelets also appear to play a role in the processing of immune complexes. Immunoglobulins and complement factors are found in several clinical situations where circulating immune complexes are expected. Furthermore, human platelets bind immune complexes in vitro and the reaction can be blocked by antireceptor antibodies to immunoglobulins and complement. These findings raise a number of questions about the role of complement in the pathophysiology of ITP.     

Immunthrombocytopenic purpura as a model for pathogenesis and treatment of autoimmunity

In honour of Professor Rossi's 80th birthday we review the development of our understanding of the immune and auto-immune nature of the pathogenesis of immune thrombocytopenic purpura (ITP). The immune aspects have been documented by postviral alterations of the cellular and humoral immune system, by new methods of specific auto-antibody detection against platelet glycoproteins and by the therapeutic effect of administering immunoglobulin concentrate from healthy blood donors. The various possible mechanisms of action of immunoglobulin treatment have led to use of this treatment as an alternative for other immune-related disorders. The treatment of severe chronic ITP in children, however, remains unsatisfactory. With a new international clinical and laboratory study of children and adolescents with early chronic ITP we are continuing the investigation of the pathogenesis and treatment of ITP.     

The role of Helicobacter pylori infection in children with acute immune thrombocytopenic purpura

The outcome of immune thrombocytopenic purpura (ITP) is classified as acute or chronic depending on whether platelet count returns to normal. The prevalence of Helicobacter pylori infection increases with age and is independent of gender. We investigated the prevalence of H. pylori infection in Chinese children from Northern Taiwan and analyzed the association between H. pylori infection and acute ITP. Our prospective cohort studies found no statistically significant relation between H. pylori infection and acute ITP. There is therefore no indication to screen children with presumed acute ITP for H. pylori infection.     

Treatment of an infant with severe acute refractory immune thrombocytopenic purpura using combination therapy including rituximab

Some infants with acute immune thrombocytopenic purpura (ITP) do not respond to first‐line therapy, and currently there is no consensus on therapy for these refractory cases. We describe a 12‐week‐old infant with acute ITP who was unresponsive to intravenous immunoglobulin and corticosteroid, and developed gastrointestinal bleeding. Several combination therapies were unsuccessful. After four doses of rituximab followed by intravenous immunoglobulin and corticosteroid, his platelet counts gradually increased. Combined therapy which includes rituximab may be a promising treatment for severe acute refractory ITP. Pediatr Blood Cancer 2009;53:203–205. © 2009 Wiley‐Liss, Inc.     

《2019年美国血液学会免疫性血小板减少症指南》儿童部分解读

免疫性血小板减少症（immune thrombocytopenia,ITP）是一种获得性自身免疫性疾病,其主要机制为血小板破坏过多及生成受阻导致血小板计数减少。一般人群中ITP的发病率为2/10万～5/10万。新版指南提供了儿童ITP一线和二线治疗方案,一线治疗方案包括观察、门诊、皮质类固醇、抗D免疫球蛋白、静脉注射免疫球蛋白（intravenous immunoglobulin,IVIG）,二线治疗方案包括利妥昔单抗、血小板生成素受体激动剂（thrombopoietin receptor agonists,TPO-RA）、脾切除术。另有一些三线药物治疗但指南未给出明确建议。     

Idiopathic thrombocytopenic purpura of childhood

Idiopathic thrombocytopenic purpura (ITP) is a benign hemorrhagic disorder characterised by peripheral thrombocytopenia and increased megakaryocytes in the bone marrow. The exact pathogenesis of ITP is not well understood. The adherence of viral induced immune complexes to the platelet membrane is thought to trigger the phagocytosis of damaged platelets by macrophages in the reticuloendothelial system. The role of platelet associated IgG in the pathogenesis of ITP is under investigation. Although spontaneous recovery is observed in 80–90% of patients, a short course of steroid therapy is recommended to reduce the duration of thrombocytopenia. The steroids however, have no influence on the course or outcome of the disease, and their possible role in reducing the incidence of intracranial hemorrhage (ICH) is unknown. Emergency management of patients presenting with signs and symptoms suggestive of ICH is essential to prevent the fatal outcome. Approximately 10–20% of patients develop chronic ITP. Splenectomy, considered the treatment of choice in these patients, is not always curative. The post-splenectomy sepsis also imposes a great risk for these individuals. Recent experience with intravenous immunoglobulin (IV IgG) treatment indicates that the splenectomy could safely be deferred, or even avoided in chronic ITP. The use of IV IgG in acute ITP is being investigated.     

Epstein-Barr virus associated with immune thrombocytopenic purpura in childhood: a retrospective study

OBJECTIVE: Although Epstein-Barr virus (EBV) is known to cause immune thrombocytopenic purpura (ITP), the epidemiology of this pathogen in children with ITP is not known. In the present study, the clinicoepidemiology and laboratory characteristics of EBV-associated ITP in childhood were analysed retrospectively. METHODS: The study cohort consisted of 108 children in whom ITP was diagnosed between 1990 and 1998. Patients were divided into EBV or non-EBV groups according to their serological status at diagnosis. RESULTS: Thirty-five (32.4%) of 108 children had ITP associated with acute EBV infection. The clinical manifestations and laboratory data were similar in children with and without acute EBV. Responses to various modalities of therapy were analysed. The average time to achieve complete remission (platelet count > or =150 x 10(9)/L) in EBV and non-EBV groups was 26 and 16 days, respectively. CONCLUSIONS: The incidence of childhood ITP associated with acute EBV infection is relatively high in Taiwan. Patients with EBV-associated ITP tended to resolve more slowly than those without EBV infection.     

Effects of COVID-19 vaccination on platelet counts and bleeding in children,adolescents, and young adults with immune thrombocytopenia

Coronavirus disease 2019 (COVID-19) vaccines rarely cause de novo immune thrombocytopenia (ITP) but may worsen preexisting ITP in adults. Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines impact platelet counts and bleeding in children, adolescents, and young adults (C-AYA) with preexisting ITP is unknown. We report here the very limited effect of COVID-19 vaccination on platelet counts and bleeding in a single-center series of 2 C-AYA with ITP. No patient experienced worsening bleeding and only one child had a significant decrease in platelet count which improved spontaneously to her baseline without intervention. SARS-CoV2 vaccination was safe in C-AYA with ITP in this small cohort.