Heparin-induced thrombocytopenia and thrombosis: a prospective analysis of the incidence in patients with heart and cerebrovascular diseases

Heparin-induced thrombocytopenia and/or thrombosis (HITT) are serious complications of heparin treatment. The incidence, as previously reported, varies widely and, in consequence, is not precisely known. Moreover, most reports only concern clinically defined heparin-induced thrombocytopenia. Therefore we carried out a prospective study of the incidence of serologically confirmed HITT.
All patients admitted to the Departments of Cardiology and Neurology of our institution with an indication for treatment with therapeutic-dose intravenous unfractionated heparin were enrolled in the study. The patients were examined daily for the occurrence of thromboembolic complications. Regular platelet counts and tests for the presence of heparin-dependent antibodies were carried out using two different tests: a quantitative platelet factor 4/heparin (PF4/hep) Elisa, and a functional test, the heparin-induced platelet activation assay (HIPAA). HITT was defined as a rapidly occurring (within 5 d) decrease of the platelet count from normal values of >120 ×10⁹ l to <60 ×10⁹ l or to <100 ×10⁹ l if there was a rapid fall of >50% of starting value or >30% with concomitant acute thrombosis.
The observed incidence of HITT was 1/358 patients (0.3%, 95% confidence limits 0.01–1.5%). However, Elisa PF4/hep specific IgG antibodes were demonstrated in nine (2.5%) and IgM antibodies in seven (2.0%) of 358 patients. 30/358 patients (8.4%) had platelet activating antibodies in the HIPAA.
We conclude that the incidence of serologically confirmed HITT in this study is very low (0.3%) in patients with cardiac and neurologic diseases treated with intravenous unfractionated heparin. The frequency of heparin-dependent antibodies without concomitant occurrence of thrombocytopenia is much higher.     

Cytokine profile of patients with chronic immune thrombocytopenia affects platelet count recovery after Helicobacter pylori eradication

Helicobacter pylori eradication induces platelet recovery in a subgroup of patients with chronic immune thrombocytopenia (cITP), but the mechanisms involved are still not understood. We aimed to evaluate the effect of H. pylori eradication on platelet response and to identify the associated serum cytokine profile in 95 patients with cITP. Serum cytokine concentrations were determined by enzyme‐linked immunosorbent assay prior to and 6 months after H. pylori eradication. Remission of cITP was observed in 17 (28·8%) of 59 patients in whom the bacterium was eradicated. Six months after treatment, a significant reduction in the concentrations of T‐helper (Th) 1 and Th17 cells and an increase in T regulatory (Treg) and Th2‐cell commitment cytokines were observed in patients who recovered, but not in those whose platelet count did not recover. Patients who had a platelet response to eradication of the bacteria had higher pre‐treatment serum levels of γ‐interferon (IFNG, IFN‐γ), transforming growth factor‐β (TGFB1, TGF‐β) and interleukin 17 (IL17A, IL‐17) than patients who did not respond, but only higher pre‐treatment TGFB1 levels was independently associated with platelet response. In conclusion, amelioration of cITP after eradication of H. pylori was linked to a more efficient suppression of Th1 and Th17 response and a more pronounced Treg cell response.     

In vitro TNF blockade enhances ex vivo expansion of regulatory T cells in patients with immune thrombocytopenia

Tumour necrosis factor‐α (TNF) is an inflammatory cytokine that is elevated in a number of autoimmune diseases including immune thrombocytopenia (ITP), a bleeding disorder characterized by low platelet counts. In vitro TNF blockade increases expansion of the regulatory T cell (Treg) IKZF2 (also termed Helios) subset in T cell‐monocyte cocultures from healthy donors, but its role on proliferative responses of Tregs in ITP patients, who have altered immunoregulatory compartment, remains unclear. TNF in CD4+ T cells from patients with chronic ITP were elevated and negatively correlated with peripheral Treg frequencies, suggesting a possible inhibitory effect of TNF on ITP Tregs. In vitro antibody neutralization with anti‐TNF in T cell‐monocyte cocultures resulted in a robust expansion of pre‐existing ITP Tregs, higher than in healthy controls. Similar to the effects of anti‐TNF antibodies, TNF blockade with antibodies against TNFRSF1B (anti‐TNFRSF1B, previously termed anti‐TNFRII) almost doubled ITP Treg expansion whereas neutralization with anti‐TNFRSF1A (anti‐TNFRI) antibodies had no effect on proliferative responses of Tregs. In addition, TNFRSF1B levels on ITP Tregs were significantly elevated, which may explain the increased susceptibility of patient Tregs to the actions of TNF blockade. Altogether, these data raise the possibility that TNF blockers, through their ability to increase Treg proliferation, may be efficacious in ITP patients.     

重组人白介素-11联合环孢素治疗糖皮质激素无效ITP的临床研究

目的：探讨重组人白介素-11(rhIL-11)联合环孢素治疗糖皮质激素无效的原发免疫性血小板减少症(ITP)的远期临床疗效及其安全性。方法选取糖皮质激素治疗无效的ITP患者60例,患者随机分为治疗组(40例)和对照组(20例)。治疗组应用rhIL-11和环孢素治疗,对照组长春新碱和静脉注射用免疫球蛋白治疗,分别在治疗前、后检测两组血小板计数,观察两组临床疗效和不良反应。结果治疗组第1个月、3个月、5个月、12个月末的有效率分别为82．5%、80．0%、72．5%和52．5%,对照组的有效率分别为55．0%、50．0%、40．0%和25．0%,治疗组均优于对照组,差异有统计学意义(P<0．05)。治疗组、对照组不良反应轻微,大多数患者耐受良好。结论 rhIL-11联合环孢素治疗糖皮质激素无效的ITP的中远期疗效满意,安全性良好,可作为理想的二线方案。     

Role of platelets in chronic liver disease and acute liver injury

Platelets contain not only hemostatic factors but also many growth factors that play important roles in wound healing and tissue repair. Platelets have already been used for the promotion of tissue regeneration in the clinical setting, such as dental implantation and plastic surgery. Thrombocytopenia, which is frequently found in patients with chronic liver disease and cirrhosis, is due to various causes such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism. However, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in chronic liver disease are poorly understood. In acute liver injury, it is reported that platelets are recruited to the liver and contribute to liver damage by promoting the induction of chemotactic factors and the accumulation of leukocytes in the liver, whereas platelets or mediators released by platelets can have a protective effect against liver injury. In this review, we highlight the recent accumulated knowledge concerning the role of platelets in chronic liver disease and acute liver injury.     

How Can I Manage Thrombocytopenia in Hemodialysis Patient? A Review

Hemodialysis (HD) is the most important treatment for patients with end‐stage renal disease (ESRD). Thrombocytopenia is a potential treatment complication related to dialysis. Under normal circumstances, the platelet count would slightly decrease within the first hour of HD, but get restored towards the end of procedure. In most patients, the platelet count can be maintained within the normal range, and the occurrence of thrombocytopenia is relatively rare in clinical practice. Therefore, the possibility of thrombocytopenia in HD patients is often ignored. Moreover, thrombocytopenia might be misdiagnosed and mistreated. At present, almost all articles on the subject, apart from some case reports, focus on pseudothrombocytopenia and heparin‐induced thrombocytopenia. In this review, we summarized various underlying causes, mechanisms, and diagnostic approaches to thrombocytopenia in HD patients. The review aims to provide a guide for clinicians interested in the causes and adequate treatment of thrombocytopenia.     

Evolving concepts of pathogenesis of heparin‐induced thrombocytopenia: Diagnostic and therapeutic implications

Heparin‐induced thrombocytopenia (HIT) is an immune reaction to heparin. It often causes severe thrombosis which may lead to limb gangrene and thrombosis‐associated death. The concept of its pathogenesis has been evolving during the past five decades. Initially, HIT was thought to be caused by disseminated intravascular coagulation. Later it became clear that HIT was mediated by an immune mechanism whereby an IgG antibody induced platelet aggregation, release of procoagulant materials and consequently thrombus formation. The antigen comprises Platelet Factor 4 (PF4) and heparin which have a tendency to form ultralarge complexes. The HIT immune response has atypical features. IgG antibody appears early without IgM precedence and lasts transiently. One explanation is that there is prior priming by bacterial infection. Another unique characteristic is that it is processed as if it is a particulate antigen involving complement activation and B cells. Antigen‐presenting cells/monocytes are also involved but the role of T cells is controversial. Recent advances have provided new insights into the underlying mechanisms of HIT‐related thrombosis. Previously, platelets were believed to play a central role; their activation and consequently the induction of blood coagulation was the basis of the hypercoagulability in HIT. More recently, several studies have provided clear evidence that neutrophil and NETosis, monocytes and endothelial cells contribute significantly to the thrombosis in HIT. These new insights may result in development of better diagnostic laboratory assays and more effective treatments for HIT.     

Trastuzumab-Induced Severe Thrombocytopenia: A Case Report and Literature Review

We present a 29-year-old woman with pT2N0M0 breast cancer, histological diagnosis of invasive ductal carcinoma, ER and PR low positive, and HER-2 (3+). The patient developed trastuzumab-induced thrombocytopenia in 6 hours after an intravenous infusion of trastuzumab at the second cycle of trastuzumab treatment with the symptom of abnormal uterine bleeding. Laboratory exam revealed a sharp drop of platelet count down to 3×10⁹/L. With the treatment of single-donor platelet transfusions, glucocorticoids, oxytocin and thrombopoietic drugs, the platelet count recovered completely in 11 days. This case was confirmed to be severe thrombocytopenia induced by trastuzumab, and retreatment with trastuzumab was not attempted. With increasing clinical utilization of trastuzumab, clinicians are likely to encounter more life-threatening trastuzumab induced severe thrombocytopenia. By this case report and literature review, we hope to increase the awareness, attach the attentions to this condition, and help with the effective treatment.     

发热伴血小板减少综合征患者病死率 及临床特征的Meta 分析

目的 对文献报道的发热伴血小板减少综合征（SFTS）患者的病死率和临床特征进行Meta 分析。 方法 计算机检索PubMed、Embase、The Cochrane Library、CMB、CNKI 和VIP 数据库。选择报告SFTS 临 床特征的无对照观察性研究,摘录有关的信息,使用STATA 11 软件对所选定的数据进行合并。结果 中国地 区21 篇文献共4 320 例,韩国地区3 篇文献共262 例实验室确诊为SFTS 的患者被纳入Meta 分析。中国地区 SFTS 患者合并病死率为16.6%（95% CI ：0.155,0.177）;韩国地区SFTS 患者合并病死率为28.8%（95% CI ： 0.104,0.471）。中国地区SFTS 患者各临床表现的合并阳性率为发热81%（95% CI ：0.680,0.941）、乏力81.3% （95% CI ：0.754,0.872）、血小板减少82.9%（95% CI ：0.713,0.945）、白细胞减少84.9%（95% CI ：0.808, 0.891）、恶心54.2%（95% CI ：0.467,0.617）、厌食77.2%（95% CI ：0.690,0.854）及出血性表现 13.8%（95 CI ： 0.103,0.172）;韩国地区SFTS 患者各临床表现的合并阳性率为发热87.7%（95% CI ：0.810,0.945）、乏力 55.2%（95% CI ：0.180,0.923）、血小板减少88.5%（95% CI ：0.819,0.950）、白细胞减少90.1%（95% CI ： 0.840,0.963）、腹泻50.9%（95% CI：0.285,0.733）及出血性表现23.4%（95% CI：0.041,0.426）。结论 发热、 乏力、血小板减少及白细胞减少为所有SFTS 患者的共同临床表现,中国地区SFTS 患者的胃肠道症状以恶心 及厌食为主要表现,而韩国地区主要以腹泻为主。