急性心肌梗死和脑梗死患者血浆中ADAMTS13的测定及意义

目的 研究急性心肌梗死(AMI)及急性脑梗死(AIS)患者血浆中血管性血友病因子(vWF)裂解酶(ADAMTS13)抗原和活性变化情况,探讨ADAMTS13在动脉血栓性疾病患者发病中的作用及意义.方法 用Frests-WF73试剂盒检测血浆中ADAMTS13的活性;用ELISA法检测ADAMTS13抗原含量;并对患者血浆vWF多聚物进行电泳分析.结果 正常对照组、AMI组和AIS组ADAMTS13抗原含量分别为(878±198)、(618±188)和(702±155)U/L;活性分别为(81.7±13.9)%,(59.2±22.1)%和(65.4±15.8)%.AMI组和AIS组ADAMTS13抗原含量及活性均显著低于正常对照组(P《0.01);vWF多聚物分析未见异常.结论 AMI及AIS患者血浆ADMATS13抗原及活性均降低,提示ADAMTS13的减少与动脉血栓性疾病的发病相关.     

ADAMTS-13活性水平检测在ITP与TTP鉴别中的意义

目的　探讨VWF裂解蛋白酶(ADAMTS -13,vWP cp)活性水平的检测在特发性血小板减少性紫癜(ITP)与血栓性血小板减少性紫癜(TTP)鉴别中的意义。方法　采用残余胶原结合实验(Residual CollagenBindingAssay)分别对35例ITP、6例TTP及32例健康人血浆ADAMTS 13活性水平进行检测。结果　ITP及TTP患者血浆ADAMTS 13活性水平[(47.6 2±2 4 . 2 2 ) %、(12 .5 4±11.6 9) % ]显著低于正常人[(78 .6 0±10 .0 3) % ](P <0 . 0 1) ,ITP患者血浆ADAMTS 13活性水平明显高于TTP患者(P<0. 0 1) ,ITP患者血浆ADAMTS 13活性水平阳性率[6 8 5 7% (2 4 /35 ) ]明显低于TTP患者[10 0 % (6 /6 ) ](P <0 . 0 1)。结论　ADAMTS 13活性水平检测在ITP与TTP鉴别诊断中具有一定的意义。     

去冷沉淀血浆制备前后ADAMTS13质量变化

目的比较去冷沉淀血浆(CRP)制备前后血管性血友病因子裂解蛋白酶(ADAMTS13)的质量变化。方法运用荧光共振能量转移法(FRET)分别测定20人份新鲜冰冻血浆(FFP)和CRP中的ADAMTS13抗原含量和活性,并比较两者之间的差异。结果 FFP和CRP中ADAMTS13抗原含量分别为(744.59±104.75)ng/ml和(720.07±91.53)ng/ml,活性分别为(126.75±49.47)%和(131.62±50.03)%,(P>0.05)。结论 CRP可代替FFP用于血栓性血小板减少性紫癜(TTP)的治疗,为补充我国现行成分血品种及其临床使用范畴提供了支持数据。     

恶性血液肿瘤中ADAMTS13活性与TSP1水平改变

目的:观察血管性血友病因子裂解蛋白酶(von Willebrand factor cleaving protease,ADAMTS13)活性、血管性血友病因子(von Willebrand factor,v WF)及凝血酶敏感蛋白1(thrombospondin 1,TSP1)水平在恶性血液肿瘤患者治疗前后的变化,并探讨其相关的临床意义。方法:收集82例恶性血液肿瘤(包括20例急性白血病,48例恶性淋巴瘤,14例多发性骨髓瘤)患者和45例与之匹配的健康对照者的血浆标本,用酶联免疫吸附试验(ELISA)检测2组血浆中的v WF抗原和TSP1水平,用残余胶原结合试验(R-CBA)检测2组血浆中的ADAMTS13活性水平。结果:初发恶性血液肿瘤患者血浆中ADAMTS13活性(71.48±19.62)%明显低于正常对照组(92.31±21.82)%(P0.05);v WF抗原水平和TSP1水平高于正常对照组(P0.05)。初发组血浆中ADAMTS13活性(71.48±19.62)%低于治疗后缓解组(89.84±20.70)%(P0.05);初发组v WF抗原水平高于治疗后缓解组(P0.05)。在82例初发恶性血液肿瘤中有25例合并感染,治疗前合并感染者的ADAMTS13活性(49.80±18.44)%明显低于无感染组(73.82±21.41)%(P0.05);感染组v WF抗原水平与TSP1水平明显高于无感染组(P0.05)。治疗过程中有8例发生了血栓事件,发生血栓事件的患者血浆中ADAMTS13活性较无血栓组明显降低(P0.05);8例急性早幼粒细胞白血病中有1例合并弥散性血管内凝血。结论:恶性血液肿瘤患者中ADAMTS13活性降低和TSP1水平升高,而发生感染及血栓事件的恶性血液肿瘤患者中ADAMTS13活性进一步降低。检测恶性血液肿瘤患者血浆中的ADAMTS13活性和TSP1水平有可能更好地预防感染及血栓事件的发生。     

影响获得性血栓性血小板减少性紫癜首次缓解期内复发的相关指标研究

目的 探讨血管性血友病因子裂解蛋白酶(ADAMTS) 13活性和抗ADAMTS13抗体表达水平,与获得性血栓性血小板减少性紫癜(TTP)于首次缓解期内复发的关系.方法 选择2008年3月至2014年6月于陕西延安大学附属医院和陕西省渭南市富平县医院诊治的37例获得性TTP患者为研究对象,按照其在首次缓解随访期内是否复发,分为研究组(n=15)和对照组(n=22).分别采用残余胶原结合试验、ELISA、免疫印迹等方法,检测两组患者的ADAMTS13活性,ADAMTS13抗原水平,抗ADAMTS13抗体,ADAMTS13抑制物,血管性血友病因子(vWF)抗原和超大分子量vWF(ULVWF)多聚体等指标,并且进行统计学分析;采用多因素非条件logistic回归分析法,评估获得性TTP患者于首次缓解期内复发的独立影响因素.本研究遵循的程序符合病例收集医院人体试验委员会所制定的伦理学标准,得到该伦理会批准,分组征得受试对象本人的知情同意,并与之签订临床研究知情同意书.结果 ①研究组患者的中位ADAMTS13活性为11％(7％～124％),低于对照组的53％(7％～151％),差异有统计学意义(u=4.018,P＜0.05).研究组与对照组患者的ADAMTS13活性显著降低率分别为53.3％(8/15)和22.7％(5/22),二者比较,差异有统计学意义(P=0.049).②37例获得性TTP患者的血浆ADAMTS13活性和ADAMTS13抗原水平呈正相关关系(rs=0.810,P=0.001).研究组患者的中位ADAMTS13抗原水平为33％(3％～99％),低于对照组的59％(3％～128％),差异有统计学意义(u=4.121,P＜0.05).研究组与对照组ADAMTS13抗原水平显著降低率分别为13.3％(2/15)和9.1％(2/22),二者比较,差异有统计学意义(P=0.008).③研究组患者的抗ADAMTS13抗体检出率为66.7％(10/15),高于对照组的36.4％(8/22),差异有统计学意义(P=0.007).④研究组患者中抗ADAMTS13抑制物检出率为46.7％ (7/15),高于对照组患者的18.2％ (4/22),差异有统计学意义(P=0.011).⑤研究组与对照组患者ULVWF多聚体检出率分别为20.0％(3/15)和13.6％(3/22),二者比较,差异有统计学意义(P=0.042).⑥多因素非条件logistic回归分析结果显示,获得性TTP患者于首次缓解期内复发的独立危险因素包括ADAMTS13活性显著降低(OR=2.95,95％ CI:1.13～6.96,P＜0.05),检出抗ADAMTS13抗体(OR=3.31,95％CI:1.08～8.19,P＜0.05),检出抗ADAMTS13抑制物(OR=3.24,95 ％CI:1.24～9.03,P＜0.05).结论 获得性TTP患者在首次缓解期内,ADAMTS13活性水平显著降低,存在抗ADAMTS13抗体及抗ADAMTS13抑制物,会显著增加疾病复发风险,可以考虑将其作为预测获得性TTP患者于首次缓解期内复发的重要指标.     

急性髓系白血病中ADAMTS13活性和vWF的水平变化及其意义

本研究观察血管性血友病因子裂解蛋白酶（ADAMTS13）活性和血管性血友病因子（vWF）抗原在急性髓系白血病（AML）患者治疗前后的变化情况,探讨相关的临床意义。收集73例初治AML患者缓解前后的血浆标本,荧光标记v WF73底物荧光共振能量转移试验（FRETS-vWF73）检测患者血浆中的ADAMTS13活性,以ELISA试剂盒检测v WF抗原量。结果表明,初治AML患者治疗缓解前的ADAMTS13活性明显低于正常对照组：（63.3±25.5）%vs（105.1±37.7）%,（P〈0.01）;vWF抗原则高于正常对照组（226.6±127.0）%vs（111.4±39.7）%,（P〈0.01）。经标准诱导化疗后缓解期患者的ADAMTS13活性明显高于治疗前组（P〈0.01）,与正常对照组比较无显著差异;vWF抗原则明显低于治疗前组（P〈0.01）,但仍高于正常对照组（P〈0.05）。初治AML患者治疗前合并感染者的ADAMTS13活性明显低于无感染组：（52.2±20.6）%vs（73.9±24.7）%,（P〈0.01）;感染组vWF抗原明显高于无感染组：（262.2±135.7）%vs（193.8±110.2）%,（P〈0.05）。伴弥散性血管内凝血（DIC）者的ADAMTS13活性明显低于无DIC组：（42.0±14.5）%vs（73.4±22.7）%,（P〈0.01）;DIC患者的vWF抗原明显高于无DIC组：（274.2±140.0）%vs（204.7±115.5）%,（P〈0.05）。结论：初治AML患者治疗前伴有ADAMTS13活性的降低和v WF的升高,以合并感染和DIC的患者表现最显著。ADAMTS13和v WF在肿瘤的发生发展,炎症和DIC的形成过程中起一定作用。     

ADAMTS13和TSP-1在糖尿病视网膜病变的意义

目的研究血管性血友病因子裂解蛋白酶(ADAMTS13)及凝血酶敏感蛋白-1(TSP-1)与糖尿病眼底视网膜病变(DR)的关系。方法选取114例糖尿病患者分为单纯糖尿病(DM)组38例和糖尿病视网膜病变(DR)组76例,同时选取30例健康体检者作为对照组。用残余胶原结合试验法检测ADAMTS13活性;同时用酶联免疫吸附试验法检测血浆中TSP-1及血管性血友病因子(vWF)抗原水平。结果 DM组患者血浆中ADAMTS13活性低于对照组,差异有统计学意义(P0.01),vWF抗原和TSP-1水平均高于对照组,差异有统计学意义(P0.01);DR组ADAMTS13活性明显低于DM组,差异有统计学意义(P0.05),vWF抗原和TSP-1水平均高于DM组,差异有统计学意义(P0.05)。结论 ADAMTS13活性降低及TSP-1水平升高可能导致糖尿病眼底视网膜病变的发生和发展。     

血栓性血小板减少性紫癜患者血浆置换前后ADAMTS 13抗原变化及临床意义

血栓性血小板减少性紫癜(TTP)是一种罕见的微血管血栓——出血综合征.该病进展迅速,临床表现多样,病死率高.TTP典型临床表现为Moschcowitz's五联征:血小板减少、溶血性贫血、发热、中枢神经系统和肾脏受累表现[1].现已证实血管性血友病因子裂解蛋白酶(ADAMTS 13)缺陷,导致超大分子量vWF多聚体(ULvWF)不能被裂解而引起血小板聚集、微血管血栓形成是TTP的重要发病机制[2-3].血浆置换(PE)是治疗该病的一种安全有效的方法,使患者的病死率由90％以上降至25％[3-4].我们对6例TTP患者进行了PE治疗,同时对患者PE前后ADAMTS13抗原含量和vWF多聚体结构进行分析,报道如下.     

血管性血友病因子裂解蛋白酶活性的检测方法及评估

血管性血友病因子裂解酶(ADAMTS13,vWF-CP)裂解血浆中具有高黏附能力的超大分子量血管性血友病因子(UL-vWF),防止血小板因其引起聚集形成血栓。ADAMTS13活性异常是临床上血栓性血小板减少性紫癜(TTP),特别是遗传性TTP和特发性TTP发病的基础。其活性的检测在TTP临床诊断和治疗上具有日益重要的意义。目前报道的一些用于检测ADAMTS13活性的方法有十余种,本文对此进行综述。     

造血干细胞移植预处理对血浆ADAMTS-13活性与vWF抗原水平的影响及其临床意义

目的:通过检测造血干细胞移植(HSCT)患者预处理前后ADAMTS-13活性及v WF抗原含量,探讨预处理过程对ADAMTS-13及v WF水平的影响及评估其临床意义。方法:取113例于苏州大学附属第一医院行造血干细胞移植患者预处理前后外周血,20例健康志愿者外周血(作为对照),采用FRETS-v WF73荧光试验检测血浆ADAM TS-13活性,ELISA法检测v WF抗原量。多数患者采取改良BUCY,部分急性淋巴细胞白血病患者予TBI+CY方案预处理,淋巴瘤患者多用BEAM等方案预处理。结果:①移植后发生血栓并发症8例,49例患者出现急性移植物抗宿主病(a GVHD)。②113例造血干细胞移植患者预处理前后ADAMTS-13活性均较正常对照组低,而v WF抗原含量均高于正常对照组(P0.05)。预处理后ADAM TS-13活性减低的患者占59.3%(69/113),其中活性减低范围在60%以上的患者占8.0%(9/113);相应的VWF抗原含量也出现增高(P0.01)。③8例血栓并发症患者ADAMTS-13活性预处理后均降低,与非血栓组有明显差异(P0.01)。活性减低超过预处理前60%的占37.5%(3/8),同时v WF抗原量增加(P0.01)。④49例a GVHD患者ADAM TS-13活性均值在预处理后降低,但是与非a GVHD患者相比没有明显差异;其中25例患者在a GVHD发生当时ADAMTS-13活性较预处理前发生了明显减低(P0.001),活性减低超过预处理前60%的占6.0%(2/35)。Logistic回归分析表明:移植预处理后ADAM TS-13活性下降超过预处理前60%,是后期发生血栓的风险因素(P0.01);而预处理后ADAM TS-13活性下降不是a GVHD发生的危险因素。结论:造血干细胞移植预处理后ADAMTS-13活性较预处理前下降,v WF抗原含量升高;血栓病人尤为明显。ADAMTS-13活性降幅超过60%是后期发生血栓并发症的危险因素,而预处理后ADAM TS-13活性减低与a GVHD的发生无关。所以ADAM TS-13活性降低是移植后血栓并发症的重要预测指标。     

ADAMTS-13 plasma level determination uncovers antigen absence in acquired thrombotic thrombocytopenic purpura and ethnic differences

BACKGROUND: The recently discovered plasma enzyme ADAMTS-13 cleaves the A2-domain of von Willebrand factor (VWF). A defective cleaving protease results in unusually large VWF multimers, which cause thrombotic thrombocytopenic purpura (TTP). AIM: Analysis of the ADAMTS-13 antigen levels in TTP patients compared with normal donors. METHODS: An antigen ELISA test was built, based on high affinity anti-ADAMTS-13 monoclonal antibodies, which were generated using genetic immunization. RESULTS: Specificity of the ADAMTS-13 antigen test was confirmed, as (i) plasma from a patient with acquired TTP but presenting without inhibitor did not contain antigen and (ii) the binding of recombinant ADAMTS-13 was inhibited by increasing amounts of normal plasma. The assay is sensitive as it can detect antigen levels as low as 1.6% of normal. The concentration in normal pooled human plasma was determined (1.03 +/- 0.15 microg mL(-1)) and arbitrarily set to 1 U mL(-1). The antigen levels in congenital TTP samples (34 +/- 21 mU mL(-1), n = 2), as well as in samples from patients with acquired TTP (231 +/- 287 mU mL(-1), n = 11), were clearly reduced when compared with normal Caucasian donors (951 +/- 206 mU mL(-1), n = 16). Remarkably, normal Chinese donors have a significantly lower antigen titer (601 +/- 129 mU mL(-1), n = 15), when compared with normal Caucasians. CONCLUSIONS: Our results show that acquired TTP patients suffer mainly from ADAMTS-13 antigen depletion, thereby indicating the importance of ADAMTS-13 antigen determination in diagnosis and patient follow-up.     

ADAMTS13 activity and the presence of acquired inhibitors in human immunodeficiency virus-related thrombotic thrombocytopenic purpura

BACKGROUND: Little is known about the pathophysiology of human immunodeficiency virus (HIV)-related thrombotic thrombocytopenic purpura (TTP). It is generally assumed that acquired ADAMTS13 deficiency is due to the presence of autoantibody inhibitors, but limited data are available regarding ADAMTS13 activity and inhibitors in such patients. STUDY DESIGN AND METHODS: By use of a collagen-binding assay, ADAMTS13 activity was analyzed at presentation in 20 patients with HIV-related TTP. The presence of inhibitors in patients with reduced ADAMTS13 activity was assessed with mixing studies. The correlation between ADAMTS13 activity and inhibitors and other laboratory and clinical parameters was assessed. RESULTS: The patients fell clearly into two groups with regard to ADAMTS13 activity. Six patients (30%) had activity within the normal range, whereas the remaining 14 patients had severely reduced levels. Of the patients with reduced activity, only 5 patients had a detectable inhibitor whereas 8 showed no evidence of an inhibitor. There was significant correlation between normal ADAMTS13 activity and lower CD4 counts (p = 0.049). von Willebrand factor (VWF) antigen levels were significantly higher in patients with reduced ADAMTS13 activity (p = 0.03). Low activity in the absence of a detectable inhibitor was associated with significantly higher D-dimer levels (p = 0.01) and worse clinical outcome. CONCLUSION: The heterogeneity with regard to ADAMTS13 activity and the absence of inhibitors in the majority of patients indicate that other factors are important in the pathogenesis of HIV-related TTP. VWF release and localized coagulation activation due to direct viral or cytokine-mediated endothelial cell injury is likely to be playing a major role.     

A phenotype–genotype correlation of ADAMTS13 mutations in congenital thrombotic thrombocytopenic purpura patients treated in the United Kingdom

Summary. Background: ADAMTS13 mutations play a role in thrombotic thrombocytopenic purpura (TTP) pathogenesis. Objectives: To establish a phenotype–genotype correlation in a cohort of congenital TTP patients. Patients/Methods: Clinical history and ADAMTS13 activity, antigen and anti‐ADAMTS13 antibody assays were used to diagnose congenital TTP, and DNA sequencing and in vitro expression were performed to identify the functional effects of the ADAMTS13 mutations responsible. Results: Seventeen (11 novel) ADAMTS13 mutations were identified in 17 congenital TTP patients. All had severely reduced ADAMTS13 activity and antigen levels at presentation. Six patients with pregnancy‐associated TTP and six patients with childhood TTP were homozygous or compound heterozygous for ADAMTS13 mutations located in the metalloprotease (MP), cysteine‐rich, spacer and/or distal thrombospondin type 1 domains. The adults had TTP precipitated by pregnancy, and had overall higher antigen levels (median, 30 ng mL^?1; range, < 10–57 ng mL^?1) than the children (median, 14 ng mL^?1; range, < 10–40 ng mL^?1). Presentation in the neonatal period was associated with more intensive treatment requirements. The two neonates with the most severe phenotype had mutations in the first thrombospondin type 1 motif of ADAMTS13 (p.R398C, p.R409W, and p.Q436H). Using transfected HEK293T cells, we have shown that p.R398C and p.R409W block ADAMTS13 secretion, whereas p.Q436H allows secretion at reduced levels. Conclusions: This study confirms the heterogeneity of ADAMTS13 defects and an association between ADAMTS13 genotypes and TTP phenotype.     

Blood group O and black race are independent risk factors for thrombotic thrombocytopenic purpura associated with severe ADAMTS13 deficiency

BACKGROUND: It has been postulated that blood group O subjects may be partially protected against thrombotic thrombocytopenic purpura (TTP) because they have lower plasma levels of von Willebrand factor. STUDY DESIGN AND METHODS: The Oklahoma TTP Registry enrolled 301 consecutive patients from November 13, 1995 (when systematic ADAMTS13 measurements began), through 2009; 281 (93%) patients had ADAMTS13 measurements. Patients were designated as having severe ADAMTS13 deficiency when the activity measurement by either method was less than 10%. ABO blood group was determined in all 281 patients. The observed frequency of blood group O was compared to the expected frequency. The association between severe ADAMTS13 deficiency and blood group, race, sex, and age were analyzed by logistic regression. RESULTS: The frequency of blood group O was unexpectedly and significantly greater than the race‐ethnicity–adjusted expected frequency in 65 patients with severe ADAMTS13 deficiency (60.0% vs. 47.4%, p = 0.042) but not in 216 patients without severe ADAMTS13 deficiency (44.9% vs. 46.5%, p = 0.639). Blood group O and race‐ethnicity were independently associated with severe ADAMTS13 deficiency among patients with TTP. The probability for severe ADAMTS13 deficiency was 45.8% with O and 32.1% with non‐O blood groups for black patients and 24.1% with O and 15.1% with non‐O blood groups for white patients. CONCLUSION: Among patients with TTP and severe ADAMTS13 deficiency the relative frequency of patients with blood group O was greater than expected, suggesting that blood group O may be a risk factor for TTP associated with severe ADAMTS13 deficiency.     

The active conformation of von Willebrand factor in patients with thrombotic thrombocytopenic purpura in remission

Summary.  Background:  Functional deficiency of ADAMTS13 in thrombotic thrombocytopenic purpura (TTP) patients is associated with circulating ultralarge von Willebrand factor (VWF) molecules that display spontaneous platelet-binding capacities. Upon remission, however, ADAMTS13 activity does not always return to baseline. Objective:  To study ADAMTS13 and VWF-related features in TTP patients in remission. Methods:  ADAMTS13 activity, anti-ADAMTS13 antibodies, VWF antigen, ultralarge VWF and levels of VWF that circulate in a glycoprotein Ibα-binding conformation were determined in plasma samples of 22 acquired TTP patients in remission between 1 month and 6 years after achieving remission. The composition of active multimers was investigated with a novel immunoprecipitation assay based on monoclonal antibody AU/VWF-a12, which specifically recognizes the active conformation of VWF. Results:  ADAMTS13 activity was undetectable in 23% of the patients, even years after they had achieved remission, and lack of ADAMTS13 activity was associated with increased active VWF levels and the presence of ultralarge VWF multimers. Active VWF levels and ultralarge VWF were also associated with blood groups. Results from immunoprecipitation experiments revealed the full range of multimers to be present. Conclusion : ADAMTS13 deficiency and the concurrent presence of ultralarge VWF and increased active VWF levels can be detected in TTP patients for years after they have achieved remission. Immunoprecipitation results suggest that the active conformation of VWF may be present in the lower molecular weight multimers, but future studies are necessary to confirm our findings.     

Interferon‐α is not elevated in idiopathic thrombotic thrombocytopenic purpura patients

Idiopathic thrombotic thrombocytopenic purpura (TTP) patients have ADAMTS13 deficiency, which is usually caused by ADAMTS13 autoantibodies. However, the triggering factors for the autoantibody production remain unclear. Interferon‐α (IFN‐α) is a cytokine involved with many autoimmune processes such as inducing the activation of peripheral dendritic cells and stimulating T cells and B cells. It also plays an important role in some autoimmune diseases. Elevated IFN‐α levels have been observed in some TTP patients and previous case reports have shown the occurrence of TTP after IFN‐α treatment. Thus, we hypothesized that high levels of IFN‐α would correlate with presence of ADAMTS13 autoantibodies. However, we did not observe elevated IFN‐α levels in 36 TTP patients (mean 5.29 pg/ml, standard deviation (SD) 26.56 pg/ml) compared to healthy controls (mean 0 pg/ml, SD 0 pg/ml), P = 0.59. IFN‐α levels of most patients (94%) were undetectable. Only two patients had increased IFN‐α levels and ADAMTS13 autoantibodies were detected in these two patients. Interestingly, both the patients had an underlying autoimmune disease. Although there have been cases of secondary TTP following IFN‐α treatment, no evidence supports a role of IFN‐α in the development of idiopathic TTP in our patient population. J. Clin. Apheresis 29:336–338 2014. © 2014 Wiley Periodicals, Inc.     

Increased elastase-alpha 1-antitrypsin complex in fulminant hepatic failure: relationship to bacterial infection and activation of coagulation.

To study the effect of infection, a frequent complication of fulminant hepatic failure (FHF), on the release of elastase from polymorphonuclear leucocytes and its inhibition in circulation we have measured the concentrations of alpha 1-antitrypsin, which binds and inhibits elastase in the circulation, and of elastase-alpha 1-antitrypsin complex, in 30 patients with FHF. Elastase-alpha 1-antitrypsin complex was significantly increased in FHF as compared to controls (303 +/- 51 micrograms/l compared to 37 +/- 5 micrograms/l; n = 10; P less than 0.001) demonstrating activation of leucocytes in FHF. Infection caused greater release of leucocyte elastase, complex levels were significantly greater in patients who were infected when compared to those who were not (463 +/- 84 micrograms/l; n = 13 compared to 180 +/- 46 micrograms/l; n = 17; P less than 0.01). Also patients who survived had significantly lower complex levels than those who did not (212 +/- 49 micrograms/l; n = 18 compared to 440 +/- 94 micrograms/l; n = 12; P less than 0.02). alpha 1-Antitrypsin activity was not significantly different from control subjects (0.99 +/- 0.06 U/ml compared to 0.97 +/- 0.05 U/ml). However alpha 1-antitrypsin activity was significantly higher in patients who survived (1.17 +/- 0.05 U/ml; n = 18) compared to those who did not (0.71 +/- 0.03 U/ml; n = 12; P less than 0.001) and patients who died had significantly lower levels than control subjects (P less than 0.01) indicating the importance of maintenance of normal inhibitor levels in patients with FHF. The leucocyte activation and release of elastase in FHF was linked to activation of the coagulation system; elastase--alpha 1-antitrypsin complex levels correlated significantly with thrombin-antithrombin III complex levels (r = 0.68; P less than 0.001) and inversely with fibrinogen (r = -0.71; P less than 0.001).