血小板生成素与慢性特发性血小板减少性紫癜的相关研究

目的探讨慢性特发性血小板减少性紫癜(CITP)患者Tpo水平及其与网织血小板(RP)、血小板计数(BPC)、骨髓巨核细胞及其成熟度的关系,以及Tpo水平在治疗中的预测作用.方法夹心酶联免疫吸附试验测定血清Tpo水平;噻唑橙染色,流式细胞仪检测RP;骨髓巨核细胞双重荧光染色后,多光子激光扫描共聚焦显微镜检测成熟度.结果22名正常对照和33例CITP患者血清Tpo水平分别为(204.05±65.70)ng/L和(345.46±222.23)ng/L(P>0.05);23例再生障碍性贫血(AA)及10例急性髓细胞白血病(AML)Tpo水平分别为(1427.62±468.84)ng/L和(596.09±462.95)ng/L,均较对照组显著升高(P<0.05);CITP组RP比例明显增高,AA组及AML组网织血小板绝对计数(RPC)明显降低;CITP患者糖皮质激素治疗无效组的Tpo水平高于有效及对照组(P<0.05).结论CITP组Tpo水平较对照组无明显升高.Tpo水平与RPC、RP比例相结合可反映骨髓血小板生成情况,鉴别血小板减少原因.Tpo水平与巨核细胞成熟度无相关性.血清Tpo水平可作为预测CITP患者对治疗反应的指标之一.     

Flow cytometry and immune thrombocytopenic purpura

Although Immune thrombocytopenic purpura is a common disorder that family physicians, internists and hematologists face in their everyday practice, its diagnosis rests only on “exclusion” and its therapy is based on algorithms where “trial and error” is the rule.Flow cytometry, if simplified and standardized, could provide a quicker and better diagnostic accuracy.Studies of the lymphocyte subset using flow cytometry and more elaborate immune studies are paving the way for a better understanding of the disease and in identification of prognostic markers. Such studies may even help stratify the first-line therapy responder and assist in the use of the arsenal of immune suppressive therapy with better precision.     

Development of thrombopoietin receptor agonists for clinical use

Summary.  Thrombopoietin (TPO) is an essential hematopoietic cytokine for megakaryopoiesis. In 2002, we demonstrated that pegylated-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) increased platelet counts in patients with chronic immune thrombocytopenic purpura (ITP) in a Phase I/II clinical trial. After the cessation of clinical trials of PEG-rHuMGDF because of severe thrombocytopenia or pancytopenia due to the development of the neutralizing antibody cross-reacting with endogenous TPO, second generation non-immunogenic TPO receptor agonists have been developed. A small molecule eltrombopag and Romiplostim were approved for clinical use by FDA in 2008 to treat patients with chronic ITP who are refractory to the prior therapy. Although the efficacy of both TPO receptor agonists is convincing for the refractory ITP, further investigation is necessary to assess the potential long-term side effects and clinical applications of these therapies for other thrombocytopenic conditions.     

Intravenous immunoglobulin G and anti-D as therapeutic interventions in immune thrombocytopenic purpura.

Immune thrombocytopenic purpura (ITP) is a disorder caused by accelerated destruction of antibody-coated platelets in the reticuloendothelial system (RES), especially the spleen. Inhibition of RES function following intravenous administration of high-dose immunoglobulin G (IVIG) or intravenous anti-D leads to rapid, albeit usually temporary, reversal of thrombocytopenia in the majority of children and adults with ITP. In emergency situations high-dose IVIG is preferred over anti-D because of the more rapid rate of platelet response; for maintenance therapy in Rh positive ITP patients (e.g. children with chronic ITP pre-splenectomy) anti-D is preferred because of its comparable efficacy to IVIG plus ease of administration and lower cost. In children with typical acute ITP and platelet counts < 20 x 10(9)/L IVIG is preferred over anti-D; however other approaches in this patient cohort should be considered before high-dose IVIG, specifically careful observation alone with therapy given only to children with clinically significant haemorrhage or short course oral prednisone at a starting dose of approximately 4 mg/kg/day. Studies are required to define the short and longer term effects of both IVIG and anti-D on the immune system in order to plan more rational use of these immunomodulatory therapies in this model autoimmune disorder.     

A multicenter retrospective analysis on therapeutic plasma exchange in immune thrombocytopenic purpura

Immune Thrombocytopenia (ITP) is an autoimmune disease characterized by thrombocytopenia and skin and mucosal bleeding. In patients with an indication for treatment, corticosteroids, intravenous immunoglobulin (IVIg) and anti-D are recommended as the first line, while splenectomy, thrombopoietin receptor agonists or rituximab are recommended second line options. Approximately 10 % of adult patients with ITP fall into the chronic refractory ITP group. Therapeutic plasma exchange (TPE) has generally been tested in patients with refractory ITP, who have failed to respond to conventional treatments, in case of bleeding or prior to surgical interventions. It has been stated that elimination of the antibodies that are held responsible in the pathogenesis of the disease has an effective role in the treatment. In this article, we present the results of 17 patients, who underwent TPE for refractory ITP, together with the literature data.     

Epidemiology and pathophysiology of immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is characterized by the presence of antiplatelet antibodies and immune platelet destruction. The disorder has been described as having a predilection for young women over men. Bone marrow megakaryocytes appear morphologically and quantitatively normal, and early platelet kinetic studies were consistent with reduced platelet survival as the primary abnormality in ITP. During the last 10-20 yr, understanding of the kinetics of this disorder has evolved with evidence that platelet survival is not as abbreviated as previously thought. Thrombopoietin levels are only minimally elevated, if at all, suggesting marrow stimulation and platelet production may not be maximized. Megakaryocyte physiology appears to be altered in ITP, also suggestive of diminished platelet production. It appears both platelet survival and production are impaired in ITP. The epidemiology of ITP is reviewed here and the pathophysiology of ITP is reconsidered.     

Coexistence of thrombotic thrombocytopenic purpura and immune thrombocytopenic purpura in an Asian woman: a case report

A 33-year-old Chinese woman with a history of immune thrombocytopenic purpura presented with heavy menstrual bleeding. She was found to have thrombocytopenia, plasma ADAMTS13 activity of 0%, and positivity for the plasma ADAMTS13 inhibitor. She was diagnosed with the coexistence of thrombotic thrombocytopenic purpura and immune thrombocytopenic purpura. The patient was treated by plasmapheresis, a glucocorticoid, and rituximab. Her platelet level returned to normal, and she was discharged 28 days after admission. The number of plasmapheresis sessions and the timing of rituximab administration may be the key aspects of management of patients with thrombotic thrombocytopenic purpura who have underlying immune dysfunction caused by diseases such as immune thrombocytopenic purpura.     

Compromised ITAM-based platelet receptor function in a patient with immune thrombocytopenic purpura

Summary.  Background:  Receptors on platelets that contain immunoreceptor tyrosine-based activation motifs (ITAMs) include collagen receptor glycoprotein (GP) VI, and FcγRIIa, a low affinity receptor for immunoglobulin (Ig) G. Objectives:  We examined the function of GPVI and FcγRIIa in a patient diagnosed with immune thrombocytopenic purpura (ITP) who had unexplained pathological bruising despite normalization of the platelet count with treatment. Methods and Results:  Patient platelets aggregated normally in response to ADP, arachadonic acid and epinephrine, but not to GPVI agonists, collagen or collagen-related peptide, or to FcγRII-activating monoclonal antibody (mAb) 8.26, suggesting ITAM receptor dysfunction. Plasma contained an anti-GPVI antibody by MAIPA and aggregated normal platelets. Aggregating activity was partially (∼60%) blocked by FcγRIIa-blocking antibody, IV.3, and completely blocked by soluble GPVI ectodomain. Full-length GPVI on the patient platelet surface was reduced to ∼10% of normal levels, and a ∼10-kDa GPVI cytoplasmic tail remnant and cleaved FcγRIIa were detectable by western blot, indicating platelet receptor proteolysis. Plasma from the patient contained ∼150 ng mL⁻¹ soluble GPVI by ELISA (normal plasma, ∼15 ng mL⁻¹) and IgG purified from patient plasma caused FcγRIIa-mediated, EDTA-sensitive cleavage of both GPVI and FcγRIIa on normal platelets. C onclusions:  In ITP patients, platelet autoantibodies can curtail platelet receptor function. Platelet ITAM receptor dysfunction may contribute to the increased bleeding phenotype observed in some patients with ITP.     

Resetting the immune system in immune thrombocytopenic purpura: immunoablative strategies

As is the case with many chronic disorders, the toxicity of treatment for refractory immune thrombocytopenic purpura (ITP) often rivals that of the disease itself. In recent years, attention has turned to strategies designed to permanently rectify the abnormal immune milieu that has permitted the production of autoreactive antibodies, thereby averting chronic administration of morbidity-causing immunosuppressive medications. Approaches that will be discussed include conventional chemotherapy, high-dose chemotherapy with and without autologous stem cell support, and allogeneic transplantation.     

Association of breast cancer and immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) and breast cancer are common disorders. Only six cases in which patients have had both diseases have been reported. We describe a 40-year-old woman who had ITP while responding to therapy for metastatic breast cancer. Given the few reported cases, the diverse presentations of thrombocytopenia during the course of each patient's breast cancer and the variable therapeutic responses of ITP, the association of breast cancer and ITP is probably coincidental.     

2种方法在治疗特发性血小板减少性紫癜长期疗效的对比

目的对比分析腹腔镜脾切除术与开腹脾切除术治疗特发性血小板减少性紫癜的围手术期结果及长期疗效。方法回顾性分析2011年1月至2015年1月该院肝胆外科124例特发性血小板减少性紫癜患者行脾切除术治疗(其中腹腔镜脾切除术68例,开腹脾切除术56例)的临床资料与随访结果。结果腹腔镜脾切除术组手术时间较开腹脾切除术组长,住院时间短,术中失血量少,术后疼痛轻,术后拔出引流管时间短,术后并发症发生率低。腹腔镜脾切除术组术后无下肢深静脉血栓(DVT)发生;开腹脾切除术组术后1例发生DVT。腹腔镜脾切除术组术后1例死于肺部感染。腹腔镜脾切除术组平均随访时间(33±11.8)个月,开腹脾切除术组平均随访时间(32±12.9)个月,腹腔镜脾切除术组中术后长期有效率为73.5%,开腹脾切除术组中术后长期有效率为76.7%(P0.05)。Kaplan-Meier分析显示,2组无复发生存率差异无统计学意义(P=0.697)。结论腹腔镜脾切除术治疗特发性血小板减少性紫癜的长期疗效与开腹脾切除术相当,但具有非常明显的微创优势。     

First-line therapies for immune thrombocytopenic purpura: re-evaluating the need to treat

Immune thrombocytopenic purpura (ITP) can be challenging to both diagnose and treat: despite the ability to detect anti-platelet antibodies, the diagnosis of ITP remains one of exclusion. Management of ITP is similarly difficult as many therapies pose potential risks that may be worse than the disease. It has been generally agreed that bleeding - not platelet count - should be the rationale for treatment. Despite the absence of prospective, controlled studies, there is consensus that bleeding risks are significantly greater in patients with platelet counts <20 x 10(9)-30 x 10(9)/L, and therefore treatment is indicated for these patients; for those with platelet counts that are higher, but still <50 x 10(9)/L, treatment is also indicated if accompanied by substantial mucous membrane bleeding. The standard initial treatment for ITP is oral corticosteroids to increase platelet counts. Intravenous immunoglobulin or anti-D immunoglobulin can also increase platelet counts and are particularly useful for stimulating rapid platelet increases before planned procedures. Splenectomy, which produces a long-lasting response in a majority of patients, is still commonly used for those who do not have long-term responses to steroid therapy and it should remain the gold standard therapy. However, splenectomy is an invasive procedure with some patients relapsing even after several years. Very rare cases of life-threatening or lethal infections may also occur at any time after splenectomy and thus physicians and patients are increasingly reluctant to advise or agree to this treatment approach. Other treatments have been evaluated to prevent or delay splenectomy, including high-dose dexamethasone, intermittent anti-D immunoglobulin infusions, and rituximab. There have been few randomized, placebo-controlled studies of these approaches, and they cannot currently be recommended as their efficacy and safety remain unclear. Thrombopoietin receptor agonists are currently under clinical investigation for the treatment of ITP and may represent an alternative treatment option in the future. The criteria for treating ITP and the benefits and risks of therapies are discussed here. Ongoing and future studies will help define the best strategies for increasing platelet counts and reducing the risk of bleeding in ITP patients.     

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.     

Four patients with both thrombotic thrombocytopenic purpura and autoimmune thrombocytopenic purpura: the concept of a mixed immune thrombocytopenia syndrome and indications for plasma exchange

Autoimmune thrombocytopenic purpura (ATP) and thrombotic thrombocytopenic purpura (TTP) are each well recognized clinical syndromes which may appear as single episodes or may have chronic relapsing courses. We present four patients negative for human immunodeficiency virus (HIV) infection who appear to have both diagnoses with either concomitant or intermingled episodes, and we review seven additional patients reported in the literature with similar features. All four of our patients are female, two have underlying connective tissue disorders, and their ATP processes came to our attention because of incomplete response of the platelet count to plasma exchange therapy (PEX) during a TTP phase (Cases 1 and 2) or development of thrombocytopenia in the absence of microangiopathy on the background of prior typical TTP episodes (Cases 3 and 4). Recognition of the ATP diagnosis in each case resulted in discontinuation of PEX (Cases 1 and 2) or not instituting PEX (Cases 3 and 4). In each instance, a satisfactory rise in platelet count followed treatment for ATP. Based upon this experience, we conclude that some individuals may have a mixed immune thrombocytopenia syndrome; careful analysis of the mechanism of thrombocytopenia, especially in recurrent episodes and in patients who respond incompletely to PEX for TTP, is important when deciding whether to initiate or continue PEX, or to consider therapies appropriate for other mechanisms of thrombocytopenia.     

大剂量胸腺肽配合治疗特发性血小板减少性紫癜的临床观察

目的观察大剂量胸腺肽配合常规措施治疗特发性血小板减少性紫癜（ITP）患者的临床疗效。方法将60例患者随机分为两组,治疗组采用胸腺肽针100 mg/d静脉滴注,同时合并使用常规治疗方法;对照组仅使用常规治疗。结果治疗组有效率为71%,对照组为50%,差异有统计学意义（P〈0.05）。结论大剂量胸腺肽可调节T淋巴细胞功能,间接调节B淋巴细胞,增强机体抵抗力,提高ITP患者的疗效,且无不良反应,是一种治疗ITP安全且有效的方法。     

GABA receptor agonists: pharmacological spectrum and therapeutic actions

From the data discussed in this review it appears that GABA receptor agonists exhibit a variety of actions in the central nervous system, some of which are therapeutically useful (Table V). GABA receptor agonists, by changing the firing rate of the corresponding neurons accelerate noradrenaline turnover without changes in postsynaptic receptor density and diminish serotonin liberation with an up-regulation of 5HT2 receptors. These effects differ from those of tricyclic antidepressants which primarily block monoamine re-uptake and cause down-regulation of beta-adrenergic and 5HT2 receptors. The GABA receptor agonist progabide has been shown to exert an antidepressant action which is indistinguishable from that of imipramine in patients with major affective disorders. The fact that: (a) GABA receptor agonists and tricyclic antidepressants affect noradrenergic and serotonergic transmission differently; and (b) tricyclic antidepressants alter GABA-related parameters challenges the classical monoamine hypothesis of depression and suggests that GABA-mediated mechanisms play a role in mood disorders. Decreases in cellular excitability produced by GABAergic stimulation leads to control of seizures in practically all animal models of epilepsy. GABA receptor agonists have a wide spectrum as they antagonize not only seizures which are dependent on decreased GABA synaptic activity but also convulsant states which are apparently independent of alterations in GABA-mediated events. These results in animals are confirmed in a wide range of human epileptic syndromes. GABA receptor agonists decrease dopamine turnover in the basal ganglia and antagonize neuroleptic-induced increase in dopamine release. On repeated treatment, progabide prevents or reverses the neuroleptic-induced up-regulation of dopamine receptors in the rat striatum and antagonizes the concomitant supersensitivity to dopaminomimetics. Behaviorally, GABA receptor agonists diminish the stereotypies induced by apomorphine or L-DOPA suggesting that GABAergic stimulation results also in an antidopaminergic action which is exerted beyond the dopamine synapse. These effects of GABA receptor agonists may represent the basis of the antidyskinetic action of these compounds which, however, remains to be fully confirmed. GABA receptor agonists reduce striatal acetylcholine turnover, an effect which occurs at doses much lower than those which affect dopamine neurons. Since hyperactivity of cholinergic neurons plays a determinant role in the pathogenesis of some parkinsonian symptoms, it is conceivable that GABAergic stimulation is effective in ameliorating Parkinson's disease.(ABSTRACT TRUNCATED AT 400 WORDS)     

小剂量利妥昔单抗治疗复发难治性原发免疫性血小板减少症的临床观察

目的 探讨小剂量利妥昔单抗治疗复发难治性原发免疫性血小板减少症(ITP)的疗效及安全性.方法 研究纳入20例复发难治性ITP患者,给予利妥昔单抗100 mg静脉滴注,每周1次,连用4周,动态观察血常规、肝肾功能及凝血功能.采用流式细胞术检测治疗前后CD3+、CD4+、CD8+、CD19+淋巴细胞数.免疫比浊法定量检测治疗前后血清免疫球蛋白(IgG、lgM、IgA)水平.用ELISA方法检测血小板膜糖蛋白抗体.治疗前后各项检测指标比较采用配对t检验.结果 治疗后中位起效时间为18d,PLT达峰值时间为(24±7)d.治疗后PLT[(124±106)×109/L]显著高于治疗前[(13±5)×109/L](P＜0.01).11例(55％)患者达完全反应(CR),4例(20％)有效(R),5例(25％)无效(NR).中位疗效持续时间为8(5～23)个月.治疗前后外周血WBC、HGB、血清免疫球蛋白以及CD3+、CD4+、CD8+淋巴细胞数无明显变化,CD19+淋巴细胞数治疗后[(50.53±29.11)×106/L]较治疗前[(125.65±14.12)×106/L]明显下降(P＜0.01).3例患者治疗前血小板自身抗体检测阳性,治疗后均为阴性.1例患者在首次输注利妥昔单抗后发生轻微不良反应.结论 小剂量利妥昔单抗是一种治疗复发难治性ITP安全有效的药物,但其最佳用药方案、长期疗效以及不良反应有待临床进一步观察验证.