359例血友病A实验室诊断数据回顾分析

目的 调查分析本院血友病A患者的实验室诊断数据,了解医院就诊血友病A临床分型、抑制物存在情况及获得性血友病的诊断思路,为临床诊断和治疗提供证据.方法 对患者进行活化部分凝血活酶时间(APTT)和Ⅷ因子活性(FⅧ∶C)检测,抑制物筛查采用APTT纠正试验做定性判断,阳性者用Nijmegen定量检测抗体.结果 359名血友病A患者以重型和中型居多(共占81％),亚临床型仅14例.抑制物筛查22例阳性,FⅧ抗体定量检测平均抗体滴度35 BU.获得性血友病1例;2例患者同时存在FⅧ∶C、FⅨ∶C低下和抑制物阳性.结论 医院就诊的血友病A患者主要为重型和中型,亚临床型少见;FⅧ抑制物筛查及抗体滴度在临床治疗方案选择中及其重要;获得性血友病诊断思路应该为实验室数据结合临床、遗传学、自身免疫性检查等.     

Nijmegen测定法的简化及其在凝血因子抑制物检测中的应用

目的:探讨简化的Nijmegen法在诊断获得性凝血因子抑制物中的临床价值。方法:通过APTT测定、APTT交叉试验、APTT孵育交叉试验以及FVⅢ:C活性、FIX:C活性测定对可疑患者进行初步诊断;采用简化的Nijmegen法对4例初步诊断存在凝血因子抑制物的患者进行抑制物的定量测定。结果:4例患者APTT均延长;APTT交叉试验和APTT孵育交叉试验结果:加1/10正常血浆及等量正常血浆均不能使延长的APTT恢复正常,而且加入等量正常血浆的APTT随着孵育时间的延长而逐渐延长;4例患者中有1例为甲型血友病并发FVⅢ抑制物,其血浆FVⅢ:C活性及FVⅢ抑制物的测定结果分别为1.0%和320BU/mL;2例为获得性甲型血友病患者,其血浆FVⅢ:C分别为0.6%和1.3%,其血浆FVⅢ抑制物分别为92BU/mL和192BU/mL;另外1例为乙型血友病并发FIX抑制物,其血浆FIX:C活性及FIX抑制物的测定结果分别为1.2%和100BU/mL。结论:简化的Nijmegen法适合于对血友病患者或者获得性血友病患者产生凝血因子抑制物的分析评价;对凝血因子抑制物的检测有利于患者的诊断、治疗及预后判断。     

获得性凝血因子Ⅷ抑制物1例并文献复习

<正>获得性凝血因子Ⅷ抑制物,又叫做获得性血友病A(acquired haemophilia A,AH-A),极其罕见,该病多发生于非血友病健康人群,目前发病机制不明,主要见于自身免疫性疾病、恶性肿瘤、药物变态反应等。获得性凝血因子Ⅷ抑制物导致患者止血、凝血及纤维蛋白溶解等机制的缺陷或异常而     

获得性血友病A的临床分析与实验室检查

为了提高获得性血友病A（acquired hemophilia A）的诊断水平,对1例获得性血友病患者的临床表现、影象学、实验检查结果进行了分析。具体包括了解患者病史,复习静脉彩超记录和分析实验室检查结果。实验室检查项目有：活化部分凝血激酶时间（APTT）、凝血酶原时间（PT）、凝血酶（TT）时间、血浆FⅧ：C、FⅨ：C、FⅪ：C和FⅫ：C。结果表明：APTT99．3秒,PT13秒,TT13．5秒,FⅧ：C2％、FⅨ：C7％、FⅪ：C9％、FⅫ：C21％。患者血浆加等量正常新鲜血浆不能使APTT延长完全纠正;患者血浆和等量正常新鲜血浆混合后于37℃温育情况下,APTT随温育时间延长而延长;患者血浆稀释10倍后加等量未稀释正常血浆重复测定结果显示：FⅧ：C6％、FⅨ：C75％、FⅪ：C95％、FⅫ：C123％。抑制物滴度测定表明：FⅧ抑制物〉32 Bethesda 单位／ml。获得性血友病A确诊后,经强的松、硫唑嘌呤治疗1月余,复查APTT为33．3秒、FⅧ：C为128％、FⅧ抑制物消失。结论：详细询问病史、分析影象学所见,进行APTT纠正试验、稀释试验和抑制物滴度测定,能减少获得性血友病的误诊和误治,免疫抑制治疗能消除FⅧ抑制物,恢复正常凝血功能。     

大疱性类天疱疮并获得性血友病A患者血浆IgG亚型及FⅧ结合表位鉴定

目的确定1例大疱性类天疱疮并获得性血友病 A 患者的临床和实验室诊断;通过体内外干预实验观察获得性血友病 A 患者体内的 FⅧ抑制物对正常人血浆及兔 FⅧ凝血活性(FⅧ:C)的影响;确定患者 FⅧ抑制物的 TgG 亚型和结构表位,以揭示该病发病的分子机制。方法用Ⅰ期法测定患者血浆 FⅧ:C;以 Bethesda 单位(BU)表示 FⅧ:C 抑制物滴度;用蛋白 A-琼脂糖柱纯化患者及正常人血浆 IgG;用活化部分凝血活酶时间(APTT)分析其对 FⅧ:C 的抑制作用;观察 FⅧ抑制物对兔血浆 FⅧ:C 活性的抑制作用;分别用抗 IgG_1、IgG_2、IgG_3、IgG_4抗体作 Western blot,结合灰度扫描确定患者血浆 IgG 亚型相对表达量;散射比浊法测定患者及正常人体内各 IgG 亚型浓度;用 FⅧ/FⅧ抑制物固相结合试验及 Western blot 鉴定患者 IgG 抗体(FⅧ抑制物)作用于 FⅧ的具体“表位”。结果①患者 APTT 明显延长,正常血浆不能纠正;FⅧ:C<1.5%,FⅧ抑制物滴度为147.8 BU;②纯化的患者 IgG 以剂量依赖方式抑制正常人混合血浆 FⅧ:C;动物实验显示患者血浆能以时间依赖方式延长兔血浆 APTT;③Western blot 结果显示 FⅧ抑制物成分主要为 IgG_4,其次为 IgG_1,FⅧ抑制物作用于FⅧ:C 的结构相对分子质量为44×10~3。散射比浊法测定结果显示患者体内 IgG_4、IgG_1含量明显高于正常人。结论研究结果证明大疱性类天疱疮并获得性血友病 A 患者体内 FⅧ抑制物对 FⅧ:C有抑制作用,FⅧ抑制物的 IgG 亚型主要为 IgG_4,其次为 IgG_1;患者 FⅧ抑制物作用于 FⅧ的表位为相对分子质量为44×10~3的肽段,揭示了该获得性血友病 A 发生、发展的分子机制。     

获得性血友病的临床研究

非血友病患者产生抗因子Ⅷ抑制物,临床又名获得性血友病。此病罕见,国内仅有个例报道,国外文献报道已逾３００例。患者出血症状严重,常危及生命。我们报道８例获得性血友病的临床及实验室诊断以及使用小剂量凝血酶原复合物（ＰＣＣ）和长疗程泼尼松治疗后长期随访的结...     

血友病A患者产生凝血因子Ⅷ抑制物的相关因素分析

目的 分析血友病A患者的临床特征,探讨其凝血因子Ⅷ(FⅧ)抑制物产生的相关因素.方法 回顾性分析113例血友病A患者的临床资料及治疗情况.用一期法检测FⅧ活性,确定血友病的严重程度;对85例经过FⅧ替代治疗的患者进行FⅧ抑制物检测,并分析FⅧ抑制物产生的相关闪素.结果 FⅧ活性检测显示113例患者中重型74例,中型27例,轻型12例.本组经FⅧ替代治疗的患者产生FⅧ抑制物的发牛率为28.24%,抑制物水平均为低滴度,均发生在中、重型患者.首次使用FⅧ持续时间、血友病患者严重程度、是否有大出血或手术大量使用FⅧ史均与FⅧ抑制物是否产生相关(P<0.05).结论 血友病A患者产生FⅧ抑制物以低滴度为主,多发生在中、重型患者.首次使用FⅧ持续时间超过5 d,中、重型.曾大出血或手术使用大剂量FⅧ等均与FⅧ抑制物产生相关.     

36例血友病A相关抑制物检测分析

目的 研究替代治疗后血友病A患者抑制物存在状况,以指导临床治疗方案的调整.方法 对病人进行活化部分凝血活酶时间(APTT)测定和Ⅷ因子活性(FⅧ:C)检测,抑制物检测采用APTT纠正试验做定性判断,阳性者用Nijmegen方法进行抗体定量检测.结果 全部36例血友病A患者替代治疗后FⅧ抑制物定性试验有2例出现阳性,FⅧ抗体定量检测抗体量分别为33BU和61BU.结论 通过对血友病A患者替代治疗后FⅧ抑制物的检测分析,有利于了解血友病A患者的替代治疗效果及预后.     

因子Ⅷ抑制物及其临床意义

FⅧ抑制物是一种可以抑制或中和F血凝血活性的同种抗体或自身免疫抗体[1]。同种抗体见于部分先天性血友病甲患者；自身免疫抗体见于非血友病患者，由此引起的疾病亦称之为获得性血友病。FⅧ抑制物一旦形成，常规治疗方法时常不能有效地控制出血，成为临床棘手的问题。1FⅧ抑制物形成的相关因素FⅧ抑制物产生的病因较为复杂。同种抗体与以下因素有关：①血友病甲的严重程度。重型患者易形成FⅧ抑制物，而轻型患者较少见[2]。FⅧ基因严重的分子缺陷造成无FⅧ蛋白合成和分泌，替代疗法的FⅧ类似异体抗原，导致免疫反应，形成同种抗体，即F…     

血友病A伴抑制物一例及其免疫耐受诱导治疗探讨

目的 探讨血友病A伴抑制物的免疫耐受诱导(immune tolerance induction,ITI)治疗,提高血友病A伴抑制物患者的诊疗水平.方法 对重型血友病A患者用APTT标准曲线一期法测定凝血因子Ⅷ(FⅧ)活性(FⅧ∶C);用Bethesda法定量测定FⅧ抗体;用长距离PCR方法检测内含子22倒位.结果 经检测发现患者为FⅧ基因22内含子倒位;ITI治疗3个月后,患者FⅧ抑制物滴度下降为0,输注FⅧ后回收率＞66%,治疗6个月后达到抑制物清除标准,停止治疗.结论 该患者是国内首例采用ITI成功治疗血友病A伴抑制物的病例,ITI是目前最有希望根除血友病抑制物的方法.     

获得性血友病A合并静脉血栓形成一例并文献复习

目的通过分析1例获得性血友病A(AHA)合并静脉血栓形成患者的临床资料并复习相关文献,提高对该病的认识。方法结合1例胃印戒细胞癌患者相关的AHA合并下肢深静脉血栓形成的临床资料及文献报道,对本病的病因学、发病机制、临床表现、诊断和治疗进行讨论。结果 AHA是由针对凝血因子Ⅷ的自身抗体导致的罕见出血性疾病,多见于老年人;与其相关的常见疾病是自身免疫性疾病、恶性肿瘤,约50%的AHA患者既往身体健康。出血最常累及软组织。AHA患者存在的各种促血栓形成因素(先天性、获得性)均有助于静脉血栓形成。AHA患者的治疗包括凝血因子替代止血治疗和抗体清除治疗,静脉血栓的抗凝治疗则有可能加重患者出血倾向。本例患者为一66岁男性胃癌患者,术前APTT延长,术后软组织血肿,血浆凝血因子Ⅷ活性(FⅧ:C)下降,FⅧ抗体滴度128BU,予糖皮质激素、丙种球蛋白、环磷酰胺(CTX)抑制抗体生成、输注FⅧ、凝血酶原复合物(PCC)止血;此后,出现右下肢静脉血栓形成;停用PCC,并予胃癌联合化疗,出血和血栓症状消失,凝血功能恢复正常。结论 AHA合并静脉血栓形成临床罕见,治疗相互矛盾。及时识别这两种疾病同时存在并采取综合性、个体化治疗措施是成功治疗的关键。     

5例获得性血友病A的诊断及其体会

目的：通过系列的实验检测和文献复习，探讨获得性血友病A（AH-A）的规范化诊断方法。方法：应用临床诊断、一般凝血检测、活化部分凝血活酶时间（APTT）温育纠正试验、稀释试验、Nijmegen法、Bethesda法测定因子Ⅷ抗体（FⅧAb）和排除试验等，诊断5例AH-A患者。结果：应用系列诊断方法检测5例AH-A患者，均获得准确的AH-A诊断。结论：所使用的系列诊断流程，对AH-A患者的诊断有临床实用价值。     

Acquired Hemophilia Presenting as Profound Hematuria: Evaluation,Diagnosis, and Management of Elusive Cause of Bleeding in the Emergency Department Setting

Background

There are numerous causes of bleeding that may present to the Emergency Department (ED). Although rare, acquired hemophilia is a potentially life-threatening bleeding disorder, with reported mortality rates ranging from 6% to 8% among patients who received proper diagnosis and treatment. Approximately two thirds of patients with this condition will present with major bleeding, the magnitude of which may necessitate urgent evaluation and care.

Objectives

The aim of this article is to provide an overview of the evaluation, differential diagnosis, and management of acquired hemophilia for the emergency physician.

Case Report

A case report of a patient who presented to the ED with gross hematuria secondary to undiagnosed acquired hemophilia is described to facilitate a review of the laboratory evaluation, differential diagnosis, and treatment of acquired hemophilia.

Conclusion

Patients with acquired hemophilia–related bleeding may present to the ED for care, given the often serious nature of their bleeding. Delayed diagnosis may postpone the initiation of targeted, effective treatments for achieving hemostasis, with potentially catastrophic consequences, particularly in patients who require emergent invasive procedures. Recognition of the potential for an underlying bleeding disorder and subsequent consultation with a hematologist are critical first steps in effectively identifying and managing a patient with acquired hemophilia who presents with bleeding.     

Human CD4+ T-cell epitope repertoire on the C2 domain of coagulation factor VIII

Summary.  Approximately 25% of severe hemophilia A patients develop antibodies (Ab) that neutralize the procoagulant function of factor (F)VIII (inhibitors). Autoimmune FVIII inhibitors may develop in individuals without congenital FVIII deficiency and cause acquired hemophilia. Low titers of anti-FVIII Ab may be present in hemophilia A patients without inhibitors and in healthy blood donors. FVIII-specific CD4+ T-cells drive the synthesis of anti-FVIII Ab. We examined the epitope repertoire of CD4+ T-cells from 15 healthy subjects, 10 hemophilia A patients without inhibitors, 11 hemophilia A patients with inhibitors, and six acquired hemophilia patients. Blood CD4+ T-cells were challenged in proliferation assays with a panel 16 overlapping synthetic peptides, spanning the sequence of the FVIII C2 domain. The sequence region 2291–2330 contained the most frequently and strongly recognized peptides in each of the four subject groups. Crystallographic B factor data and the location of these peptides within the three-dimensional structure of the C2 domain confirm that this region has a high degree of solvent exposure and flexibility within the peptide backbone, which are structural features typical of immunodominant universal CD4+ epitopes. Furthermore, this sequence region overlaps inhibitor-binding sites, suggesting that CD4+ T-cells recognizing peptide sequences within this region might be involved in inhibitor synthesis. The sequence regions 2191–2210 (recognized strongly by each study group except hemophilia A patients with inhibitors) and 2241–2290 (recognized primarily by acquired hemophilia patients and healthy subjects) share the same structural features, and also overlap inhibitor-binding sites. Although similar, there appear to be important differences in the CD4+ epitope repertoires of congenital and acquired hemophilia patients.     

In non‐severe hemophilia A the risk of inhibitor after intensive factor treatment is greater in older patients: a case–control study

Summary. Background: Twenty‐five percent of new anti‐factor VIII (FVIII) antibodies (inhibitors) that complicate hemophilia A occur in those with mild and moderate disease. Although intensive FVIII treatment has long been considered a risk factor for inhibitor development in those with non‐severe disease, its strength of association and the influence of other factors have remained undefined. Objective: To evaluate risk factors for inhibitor development in patients with non‐severe hemophilia A. Methods: Information on clinical and demographic variables and FVIII genotype was collected on 36 subjects with mild or moderate hemophilia A and an inhibitor and 62 controls also with mild or moderate hemophilia A but without an inhibitor. Results: Treatment with FVIII for six or more consecutive days during the prior year was more strongly associated with inhibitor development in those ≥ 30 years of age compared with those < 30 years of age [adjusted odds ratio (OR) 12.62; 95% confidence interval (CI), 2.76–57.81 vs. OR 2.54; 95% CI, 0.61–10.68]. Having previously received < 50 days of FVIII was also not statistically associated with inhibitor development on univariate or multivariate analysis. Conclusions: These findings suggest that inhibitor development in mild and moderate hemophilia A varies with age, but does not vary significantly with lifetime FVIII exposure days: two features distinct from severe hemophilia A.     

Treatment and prevention of bleeding in congenital hemophilia A patients with inhibitors

The treatment of bleeding in hemophilia A patients with persistent inhibitory antibodies to factor VIII is problematic. The current standard hemostatic agents for inhibitor patients are recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (APCC). These “inhibitor bypassing agents” are less reliably effective than are replacement therapies for patients without inhibitors, and there are no validated laboratory assays to monitor their efficacy. Furthermore, only single rFVIIa and APCC products are available worldwide, and their use can be complicated, albeit rarely, by thrombotic events. For all these reasons, new approaches to treat bleeding in inhibitor patients are eagerly awaited. These new approaches include replacement therapy with porcine factor VIII concentrate (currently approved for use in acquired hemophilia patients), bispecific antibodies to simulate the biologic function of factor VIII (already in use in some jurisdictions), pegylated forms of activated factor VII, and strategies targeting the natural anticoagulants TFPI and antithrombin, which create a hypercoagulable phenotype to counterbalance the hypocoagulability imposed by hemophilia.     

Novel assays in the coagulation laboratory: a clinical and laboratory perspective

The ability to monitor Factor VIII (FVIII) and Factor IX (FIX) levels is integral to the clinical management of hemophilia A and B patients, respectively. Factor activity levels are checked during regular follow-up, post-infusion of factor concentrates, during pre- and post-operative assessments, and when the presence of an inhibitor is suspected. However, the ability to accurately and reproducibly measure factor activity levels with standard coagulation assays has been challenging due to the emergence of recombinant factor concentrates with extended half-lives. Similarly, special considerations must be given to the type of inhibitor assay used in patients with acquired hemophilia receiving recombinant porcine FVIII replacement. Alternative approaches to achieve hemostasis with clotting factor mimetics and interference of endogenous anticoagulants lack standardized assays for monitoring hemostatic efficacy. Laboratory assays measuring dynamic clotting parameters such as thrombin generation or whole blood viscoelasticity may provide a way forward, but have yet to enter routine clinical use. This review highlights the role of specialized coagulation assays in an era where multiple new hemostatic therapeutics for hemophilia are available, and underscores the need for clear communication between bedside and laboratory clinicians.     

Immunoadsorption for the Treatment of Acquired Hemophilia: New Observational Data,Systematic Review,and Meta-Analysis

The treatment of patients with acquired hemophilia is challenging due to life-threatening hemorrhages, delayed response, and adverse effects to immunosuppressive agents. Even though immunoadsorption (IA) rapidly removes autoantibodies against factor VIII, this intervention's effectiveness is still a matter of debate. We aimed to study important outcomes of IA as adjunctive treatment in patients with acquired hemophilia. We performed comprehensive literature searches in MEDLINE and EMBASE databases. Clinical and laboratory data of all patients treated in our institution were additionally included. Literature searching yielded 498 records, of which 10 studies describing 106 patients were finally included. The number of patients varied from 1 to 65, and patients' ages ranged between 14 and 89. Treatment criteria in most patients were (1) failed response to immunosuppressive treatment alone, and/or (2) uncontrollable bleeding episodes, and/or (3) high inhibitor titer. Methodological quality was moderate. The number of IA sessions varied from 1 to 24. Within our institution, 12 patients have been treated since 2002; median age was 76 years (range 34-86); median titer of factor VIII inhibitor was 20 Bethesda units (range 3-214). Pooled estimates, modeling a random-effect binominal distribution incorporating the Freeman-Tukey double arcsine transformation, were 86% in case of factor VIII recovery (95% confidence interval 76%-94%), 95% for reduction of factor VIII inhibitor (83%, 100%), and 7% in case of death (0%, 18%). Our data suggest that IA might be a beneficial adjunctive treatment in patients with high-risk acquired hemophilia, but future studies shall confirm this observation.