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Background:  Autoimmune thrombotic thrombocytopenic purpura (iTTP) is caused by autoantibody-mediated severe a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13) deficiency leading to micro-angiopathic haemolytic anaemia (MAHA) and thrombocytopenia with organ damage. Patients survive with plasma exchange (PEX), fresh frozen plasma replacement and corticosteroid treatment. Anti-CD20 monoclonal antibody rituximab is increasingly used in patients resistant to conventional PEX or relapsing after an acute bout., Objective:  This retrospective observational study focused on the relapse rate and possible influencing factors including treatment with rituximab first introduced in 2003., Patients and Methods:  Seventy patients treated between January 2003 and November 2014 were evaluated. Number, duration, clinical manifestations, laboratory data and treatment of acute episodes were documented. Diagnostic criteria of acute iTTP were thrombocytopenia, MAHA, increased lactate dehydrogenase and severe ADAMTS13 deficiency., Results:  Fifty-four female and 16 male patients had a total of 224 acute episodes over a median observation period of 8.3 years. The relapse rate was 2.6% per month, for women 2.4% and for men 3.5% per month. Since 2003, 17 patients with a first iTTP episode were treated with rituximab, whereas 28 were not. There was a trend towards lower relapse rates after rituximab treatment over the ensuing years. However, this was statistically not significant., Conclusion:  This analysis does not show a significant reduction of acute iTTP relapses by rituximab given during an acute bout. Initial episodes are characterized by more severe clinical signs compared with the less severe relapses. Furthermore, men suffer significantly more frequent and considerably more serious acute relapses., Competing Interests: The authors declare that they have no conflicts of interest relevant to the manuscript. I. Scharrer is a member of the Data Safety Monitoring Board in the BAX 930 study (investigating recombinant ADAMTS13 infusion in hereditary TTP). She received travel and accommodation support for participating at scientific congresses or meetings from Bayer and NovoNordisk. B. Lämmle is chairman of the Data Safety Monitoring Board in the BAX 930 study (investigating recombinant ADAMTS13 infusion in hereditary TTP). He is on the Advisory Board of Ablynx for the development of caplacizumab. He holds a patent on ADAMTS13 and received travel and accommodation support for participating at scientific congresses or meetings from Baxalta, Siemens, Alexion, Ablynx and Bayer and speaker's fees from Siemens, Bayer and Alexion., (Georg Thieme Verlag KG Stuttgart · New York.)

Unlabelled: We report on our patient (case 2) who experienced a first acute episode of thrombotic thrombocytopenic purpura (TTP) at the age of 19 years during her first pregnancy in 1976 which ended in a spontaneous abortion in the 30th gestational week. Treatment with red blood cell concentrates was implemented and splenectomy was performed. After having suffered from several TTP episodes in 1977, possibly mitigated by acetylsalicylic acid therapy, an interruption and sterilization were performed in 1980 in her second pregnancy thereby avoiding another disease flare-up. Her elder sister (case 1) had been diagnosed with TTP in 1974, also during her first pregnancy. She died in 1977 during her second pregnancy from a second acute TTP episode., Diagnosis: In 2013 a severe ADAMTS13 deficiency of <10% without detectable ADAMTS13 inhibitor was repeatedly found. Investigation of the ADAMTS13 gene showed that the severe ADAMTS13 deficiency was caused by compound heterozygous ADAMTS13 mutations: a premature stop codon in exon 2 (p.Q44X), and a missense mutation in exon 24 (p.R1060W) associated with low but measurable ADAMTS13 activity., Conclusion: Genetic analysis of the ADAMTS13 gene is important in TTP patients of all ages if an ADAMTS13 inhibitor has been excluded.

Unlabelled: We report on 21 patients with idiopathic thrombotic thrombocytopenic purpura (TTP) whose courses of disease have been followed from the respective diagnosis until now. They had a documented ADAMTS13 activity below 5%, a high autoantibody titer and detectable ultralarge von Willebrand factor (VWF) multimers during their episodes. The initial diagnosis was based on clinical symptoms and on laboratory parameters: thrombocytopenia, haemolytic anaemia, schistocytes and an increased LDH level. 103 acute clinical episodes of 21 TTP-patients during a time period of 30 years are described. Case histories, comorbidities and sequelae were retrospectively documented., Results, Conclusion: Although patients are consistently in a prothrombotic status, clinical acute manifestations only occur after triggering. Most common trigger factors are gastrointestinal infections and pregnancy. The relapse risk per month is 0.026; men have a higher risk for relapses (0.044) than women (0.021). Patients recover physically well, except for renal insufficiency in four cases. Nevertheless, major portion of patients suffers persistently from depression, anxiety disorders and persistent neurocognitive impairments.

Unlabelled: An adequate number of qualified haemophilia centres is an essential requirement for effective and cost-efficient haemophilia care. During a reassessment of the delivery of haemophilia care in Germany a broad range of criteria relating to structure and quality of the centres were defined and a questionnaire was developed., Results: Of 137 doctors who received the questionnaire, 113 (82%) replied. Based on data related to diagnostic and treatment services, together with voluntary information from PEI forms (Paul Ehrlich Institut, Germany), 72 haemophilia centres were established. Three levels of haemophilia care were defined by the Medical Advisory Council of the German Haemophilia Society. This is in accordance with criteria defined by European working parties. 17 haemophilia centres were designated CCC (Comprehensive Care Centre), 24 were designated HTC (Haemophilia Treatment Centre) and 31 smallest centres were allocated the status HTR (Haemophilia Treatment Regional). In comparison to the survey in 2007, there was only slight variance in the CCC centres (+ 2 centres/-1 centre). From the previous HTC centres, 7 have withdrawn from this treatment level: 4 maintain treatment on the lower level HTR, and 3 centres had ceased treatment. On the HTR level of treatment, 6 of 29 (21%) had ceased to offer treatment. 9 had been able to increase the number of patients and were designated HTC. 5404 patients with haemophilia and 3047 with the severe form of haemophilia were reported. 67% were treated in CCC, 25% in haemophilia treatment centres and 8% in the 31 smallest centres. 13 of the adult CCC are situated in the department of internal medicine and 4 in the section of transfusion medicine., Conclusions: The survey and analysis of the haemophilia treatment centres in Germany show that the delivery of haemophilia care through 17 CCC, 24 HCT and 31 HTR appears to be adequately structured. But it is noticeable and alarming, however, that on both HTC and HTR levels of treatment, 32% and 21%, respectively, have left their treatment level. 9 centres (12.5%) have finished working in haemophilia care in the last four years. On the strength of these results, endeavours to maintain haemophilia centres must be intensified. A high level of effective care can be guaranteed only through continued existence of the centres.

Unlabelled: 76 German patients suffering from thrombotic thrombocytopenic purpura (TTP) were interrogated about the prevalence of co-occurring autoimmune disorders. In order to analyze a possible association of TTP with the questioned diseases, a comparison of prevalence rates between the patient group and the general population has been made for each disease., Results: Compared to the estimated prevalence rates, the statistical analysis revealed an unexpected high occurrence of the following disorders within the patient group: Hashimoto's thyroiditis (23.5% within the patients compared to 0.7% within the general population, p<0.001), systemic lupus erythematosus (SLE) (6.5% in patients to 0.025% in the general population, p<0.001), immune thrombocytopenic purpura (ITP) (6.3% in patients to 0.02% in the general population, p<0.001), psoriasis (9.4% in patients to 2.5% in the general population, p=0.005) and celiac disease (3.1% in patients to 0.2% in the general population, p=0.007)., Conclusion: These findings confirm the mentioned tendency of autoimmune diseases to co-occur in one individual and argue once more for a genetic susceptibility in idiopathic TTP as well as in autoimmune disorders.

Over the past years, there has been a dramatic increase in the number of identifiable causes of thrombophilia. However, to date, there are no large, prospective studies to assess an optimal, cost-effective approach with regard to screening and case finding for thrombophilic risk factors in patients presenting with retinal vessel occlusion. Two hundred twenty-eight patients with retinal vein occlusion (RVO) and 130 age-matched healthy controls were prospectively screened for thrombophilic risk factors. Both cohorts were divided into three subgroups, depending on the patients' age at the time of the RVO or a previous thromboembolic event. Patient age < or =45 years was associated with a high prevalence of coagulation disorders (p<0.0001). Among patients < or =45 years and >45 to < or =60 years, a family history of thromboembolism was strongly associated with the presence of thrombophilic disorders. The absence of cardiovascular risk factors was found to be a strong predictor for the presence of coagulation disorders in all patient groups (< or =45 years, p=0.003; >45 to < or =60 years, p=0.0008; >60 years, p=0.001). Multivariate analysis revealed the presence of resistance to activated protein C (p=0.014), antiphospholipid antibodies (p=0.022), and deficiency of the anticoagulant proteins (p=0.05) as independent risk factors for the development of RVO among patients < or =45 years. Our results indicate that thrombophilic disorders are associated with the development of retinal vein occlusion in patients < or =45 years by the time of the RVO or a previous thromboembolic event, in patients with a family history of thromboembolism, or in patients without cardiovascular risk factors.

Background: The potential impact of coagulation abnormalities on retinal vascular occlusive diseases, individually and in combination with cardiovascular risk factors, remains unclear., Patients and Methods: In a prospective case-control study a cohort of 74 young patients with central, hemicentral or branch retinal vein occlusion (RVO) (

Background: The potential impact of coagulation abnormalities on non-arteritic ischaemic optic neuropathy (NAION), individually and in combination with cardiovascular risk factors, remains unclear., Patients and Methods: In a prospective case-control study a cohort of 26 NAION patients < 60 years at the time of the NAION or a previous thromboembolic event and 50 subjects matched for age and sex were prospectively screened for thrombophilic risk factors., Results: Overall, thrombophilic defects were found to be present in 12 of 26 patients (46.2 %) and in 9 of 50 (18 %) controls (p = 0.01). The most frequent coagulation disorders were high levels of factor VIII (p = 0.04) and lipoprotein (a) (p = 0.03). Moreover, we identified two patients with homozygous resistance to activated protein C, which is the first description of this coagulation disorder associated with NAION. Patients without cardiovascular risk factors had a statistically significant higher frequency of coagulation disorders than patients with these risk factors (p = 0.038)., Conclusions: Our results indicate that thrombophilic disorders are associated with the development of non-arteriitic ischaemic optic neuropathy in patients < 60 years of age at the time of a first thromboembolic event. Selective screening of young patients and patients without cardiovascular risk factors may be helpful in identifying NAION patients with thrombophilic defects.

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Treatment of relapsed or refractory autoimmune mediated haemolytic syndromes, such as autoimmune haemolytic anaemia (AIHA) and thrombotic thrombocytopenic purpura (TTP), represents a therapeutic challenge. Here we report on our experience with the monoclonal anti-CD20 antibody rituximab (R) compared to standard treatment in these diseases. Patients with non-familial TTP or AIHA and no underlying malignancy were included in our analysis. Safety and efficacy of R-treatment were compared to results obtained in standard treatment approaches. Altogether, 27 patients were analyzed, comprising 15 patients with TTP and 12 patients with AIHA. The patients' average age at the time of diagnosis was 54 years. Eleven patients received antibody treatment (8 TTP, 3 AIHA). No acute or late WHO grade III/IV toxicity associated with rituximab was noted. With standard therapy, the overall response rate (ORR) was 66.7% for AIHA and 65.8% for TTP, respectively. For the R-containing regimens the ORR was 100%. In patients with TTP, median progression free survival (PFS) with R-treatment was 3.8 years, as compared to 0.1 years in the standard-treatment group. In patients with AIHA median PFS was not reached for R-containing treatment; all patients are in sustained remissions with a median follow up of 12.5 months. In the absence of prospective trials, our data underline the safety and efficacy of rituximab in relapsed and refractory autoimmune anaemias with favourable response rates and promising long-term progression-free survival. Therefore, prospective clinical trials evaluating rituximab as salvage- and first-line-therapy are clearly warranted.

In patients with chronic liver disease profound coagulation changes and thrombocytopenia may lead to life-threatening bleeding that requires thorough diagnosis and immediate blood product replacement.

A minority of patients presenting with acute life threatening syndromes characterized by severe bleeding episodes or microvascular thromboses on the intensive care unit. Especially patients with TTP, HUS, acquired haemophilia and CAPS have a poor prognosis. These emergency cases require a rapid diagnosis and an immediate onset of treatment.

Replacement therapy of coagulation factor preparations (AT, FFP, PPSB, FXIII, rFVIIa) are frequently used on the Intensive Care Units. Indications, dosage, specific effects and side effects have to be considered.

From 1998 to 2003, 133 Caucasian women aged 17-40 years (median 29 years) suffering from unexplained recurrent miscarriage (uRM) were consecutively enrolled. In patients and 133 age-matched healthy controls prothrombotic risk factors (factor V (FV) G1691A, factor II (FII) G20210A, MTHFR T677T, 4G/5G plasminogen activator inhibitor (PAI)-1, lipoprotein (Lp) (a), protein C (PC), protein S (PS), antithrombin (AT), antiphospholipid/anticardiolipin (APA/ACA) antibodies) as well as associated environmental conditions (smoking and obesity) were investigated. 70 (52.6%) of the patients had at least one prothrombotic risk factor compared with 26 control women (19.5%; p<0.0001). Body mass index (BMI; p=0.78) and smoking habits (p=0.44) did not differ significantly between the groups investigated. Upon univariate analysis the heterozygous FV mutation, Lp(a) > 30 mg/dL, increased APA/ACA and BMI > 25 kg/m(2) in combination with a prothrombotic risk factor were found to be significantly associated with uRM. In multivariate analysis, increased Lp(a) (odds ratio (OR): 4.7/95% confidence interval (CI): 2.0-10.7), the FV mutation (OR:3.8/CI:1.4-10.7), and increased APA/ACA (OR: 4.5/CI: 1.1-17.7) had independent associations with uRM.

The clinical presentation of VWD shows sex-related differences of symptoms. In women the most typical symptoms are menorrhagia, bleeding during and after delivery or abortion and bleeding in connection with caesarean section or gynaecological surgery. Menorrhagia is one of the most common symptoms presented to gynaecologists. In 7-20% of menorrhagia the underlying cause is VWD, in our cohort of 185 women with menorrhagia the prevalence of VWD was even 32%. On the other hand in women with VWD menorrhagia with onset at the menarche can be found in 60-93%, influencing substantially their morbidity and quality of life. During pregnancy women with mild VWD experience a decrease of bleeding tendency due to an increase of endogenous VWF. But as the VWF concentration drops rapidly after delivery, the post-partum period is often associated with significant bleeding complications. In severe forms of VWD the bleeding risk is high during delivery and postpartum period. Laboratory monitoring and therapeutical measures should be continued for 8-10 days after delivery. During menopause the clinical situation improves for most of the women with mild or moderate VWD.

ACE displays potent vasoconstrictive effects, attenuation of fibrinolysis, and platelet activation and aggregation, thus possibly promoting venous thromboembolism (VTE). The ACE gene contains an insertion (I) or deletion (D) polymorphism accounting for 50% of the variation in serum ACE concentration. To evaluate the role of the I/D polymorphism in VTE, its prevalence was determined in 931 patients with VTE and 432 blood donors. The prevalence of the DD genotype was 27.6% in patients and 21.3% in controls (OR 1.4; p < 0.02). In multivariate analysis there was a trend of the DD genotype to be an independent risk factor (OR 1.4; p = 0.08). No differences in DD genotype prevalence according to exogenous risk factors were found. Coinheritance of FV G1691A, PT G20210A mutation, and PS deficiency with the DD genotype increased the relative risk of VTE. Thus, the ACE DD genotype is a moderate risk factor of hereditary thrombophilia. Exogenous risk factors did not alter the manifestation of VTE among carriers of the DD genotype, whereas coinheritance of the DD genotype with the aforementioned defects increased the risk for VTE considerably.

Background: The endothelial cell protein C receptor (EPCR) enhances protein C activation by the thrombin-thrombomodulin complex. As evidence is accumulating that EPCR is an important component of the protein C anticoagulant pathway, polymorphisms in the EPCR gene might be candidate risk factors predisposing to venous thromboembolism (VTE). Recently, a 23bp insertion in exon 3 of the EPCR gene has been identified, which duplicates the preceding 23 bases and results in a STOP codon downstream from the insertion point. However, the clinical significance of this mutation in VTE remains to be clarified., Methods and Results: In this study we evaluated the EPCR 23bp insertion in 889 patients with documented VTE and in 500 healthy controls. The prevalence of the EPCR insertion among patients was 0.1%, which was not significantly different compared to controls (0.6%, p = 0.1)., Conclusions: Our findings showed that the EPCR 23bp insertion is very rare in both patients with VTE and the general population and failed to support an association between the EPCR 23bp insertion and an increased risk of VTE.

To add an increased level of safety to antihemophilic factor replacement therapy, a full-length, recombinant Factor VIII (rFVIII) product has been developed without human-derived plasma proteins during purification and formulation and using an additional solvent/detergent viral inactivation step. This first clinical trial of a sucrose-formulated full-length rFVIII (rFVIII-FS) was conducted in previously treated patients (> or = 100 prior exposure days) with severe (<2% FVIII) hemophilia A in North America (NA) and Europe (EU). Pharmacokinetic profiles for rFVIII-FS were compared with those of currently licensed rFVIII product (Kogenate) in 35 patients. Safety and efficacy during home therapy were evaluated in 71 patients. The new formulation displayed a pharmacokinetic profile similar to that of rFVIII. Patients on home therapy received a cumulative total of 11,867 exposure days, 12,546 infusions, and 22,443,694 IU of rFVIII-FS. Of 2585 bleeds, 93.5% were treated with 1-2 infusions and 80.5% of responses were rated as excellent or good. No evidence of de novo inhibitor formation was observed. Only 0.27% of infusions were associated with any drug-related adverse event. Except for an episode of intermittent chest pain with palpitations which ceased after treatment with analgesics, associated adverse events were mild or moderate. Overall, rFVIII-FS provided excellent hemostatic control, was well-tolerated, and caused no significant adverse effects, thus demonstrating safety and efficacy for treatment of bleeds in patients with hemophilia A.

Because it contains three pairs of polypeptides, fibrinogen isolated from heterozygous individuals is expected to be a mixture of homodimers and heterodimers. Nevertheless, heterozygous individuals with only homodimers have been identified. We synthesized two recombinant fibrinogens with the mutations from fibrinogen Vlissingen/ Frankfurt IV (gamma(delta)319, 320) and Matsumoto I (gammaD364H), both identified in heterozygous individuals. We found that polymerization of these fibrinogens was undetectable in 30 min; polymerization of a 1:1 mixture of variant and normal fibrinogen was the same as polymerization of a 1:1 mixture of buffer and normal fibrinogen; polymerization of either plasma fibrinogen was markedly impaired when compared to the 1:1 mixture of the respective variant and normal fibrinogens. We conclude that each plasma fibrinogen is a mix of homodimers and heterodimers, such that the incorporation of heterodimers into the fibrin clot impairs polymerization. We suggest that incorporation of heterodimers can induce clinical symptoms.

Except for bleeding complications, relevant adverse effects of coumarin anticoagulants are comparatively rare considering the widespread use of these substances. Here we present the case of a 56-year-old woman who developed recurrent episodes of severe hepatitis following repeated exposure to phenprocoumon (Marcumar; Roche, Grenzach-Wyhlen, Germany) and warfarin (Coumadin; DuPont Pharma, Bad Homburg, Germany) after replacement of the mitral valve with a mechanical prosthesis. The diagnosis of "coumarin-induced hepatitis" is compatible with the time relationship between start of the drug and the onset of hepatopathy (first episode 8 months, second episode 4 weeks, and third episode 7 days), the rapid improvement following discontinuation of the drug, recurrence of liver dysfunction after re-exposure to the drug, and liver histology. After anticoagulant therapy was changed to heparin and acenocoumarol (Sintrom; Ciba-Geigy, Basel, Switzerland), the patient's general state was markedly improved and her liver values became almost normal. This case will be discussed and compared with other reports of coumarin-induced hepatic lesions. Although liver damage induced by coumarin derivates is rare, it is important to be aware of the hepatotoxic potential of these drugs, which, in most cases, mimics the clinical presentation of viral hepatitis.

In this open multicenter study the safety and efficacy of recombinant factor VIII (rFVIII) was assessed in 39 previously treated patients with hemophilia A (factor VIII basal activity < or = 15%). Recombinant FVIII was administered for prophylaxis and treatment of bleeding episodes and for surgical procedures. A total of 3679 infusions of rFVIII were given. Efficacy of rFVIII as assessed by subjective evaluation of response to infusion and mean annual consumption of rFVIII was comparable to that of plasma derived FVIII concentrates. The incremental recovery of FVIII (2.4 +/- 0.83%/IU/kg, 2.12 +/- 0.61%/IU/kg, resp.) was within the expected range. No clinical significant FVIII inhibitor was detected in this trial. Five of 16 susceptible patients showed a seroconversion for parvovirus B19. However, the results are ambiguous in two cases and might be explained otherwise in one further case. Thus, in two patients a reliable seroconversion for parvovirus B19 was observed.

We investigated the presence of the gene mutation of factor V, FV R506Q or factor V Leiden, responsible for activated protein C resistance, in DNA samples of 127 probands and 188 relatives from 128 families with antithrombin deficiency. The factor V mutation was identified in 18 families. Nine families were available to assess the mode of inheritance and the clinical relevance of combined defects. The factor V and antithrombin genes both map to chromosome 1. Segregation of the defects on opposite chromosomes was observed in three families. Co-segregation with both defects on the same chromosome was demonstrated in four families. In one family a de novo mutation of the antithrombin gene and in another a crossing-over event were the most likely explanations for the observed inheritance patterns. In six families with type I or II antithrombin deficiency (reactive site or pleiotropic effect), 11 of the 12 individuals with both antithrombin deficiency and the factor V mutation developed thrombosis. The median age of their first thrombotic episode was 16 years (range 0-19); this is low compared with a median age of onset of 26 years (range 20-49) in 15 of 30 carriers with only a defect in the antithrombin gene. One of five subjects with only factor V mutation experienced thrombosis at 40 years of age. In three families with type II heparin binding site deficiencies, two of six subjects with combined defects experienced thrombosis; one was homozygous for the heparin binding defect. Our results show that, when thrombosis occurs at a young age in antithrombin deficiency, the factor V mutation is a likely additional risk factor. Co-segregation of mutations in the antithrombin and factor V genes provides a molecular explanation for severe thrombosis in several generations. The findings support that combinations of genetic risk factors underly differences in thrombotic risk in families with thrombophilia.

We have identified a patient with a dysfunctional prothrombin that we have designated Prothrombin Frankfurt. The proband was characterized by a prothrombin activity level of 13% and 20% compared to normal controls using two different assays with a normal prothrombin antigen level of 91% of normal controls. The genetic defect responsible for the abnormal prothrombin activity was determined by the polymerase chain reaction followed by single-strand conformation polymorphism (PCR-SSCP) analysis and by DNA sequence analysis of the human prothrombin gene. Substitution of a C for an A at nucleotide 10177 in the human prothrombin gene of the proband was identified, which results in the replacement of Glu-466 by Ala. The proband and one sister were homozygous for this mutation. Both parents, as well as one brother, were found to be heterozygous for this mutation. The same amino acid substitution was previously identified to be responsible for the dysfunctional protein Prothrombin Salakta and was hypothesized to result in altered substrate specificity. Four polymorphisms were also identified in the prothrombin gene from the proband when compared to the published sequence at nucleotides 554, 4048, 4272 and 10253.

The determination of the bleeding time (BT) is an essential diagnostic tool for von Willebrand's disease (vWD). However, the standardized Simplate BT still displays many variables and disadvantages. The present study reports on the sensitivity of the in vitro bleeding test (IVBT) in 51 vWD cases of different types and severity in comparison to the Simplate BT, and the correlation of both to each other as well as to von Willebrand factor (vWF:RCo) activity. The IVBT was performed in two modifications (2 mmol/L CaCl2 and 4 mmol/L ADP) on the Thrombostat 4000. The IVBT, particularly with CaCl2, showed clearly higher sensitivity than the BT (CaCl2: 84.3%, ADP: 61.7%, CaCl2 + ADP: 86.3, BT: 52.9%). The BT even failed in one patient with severe (type 2B) and in three with moderate vWD. The IVBT only failed in very mild forms of the disease (vW-F:RCo > 25%). In addition, the IVBT with ADP showed a close correlation to the vWF:RCo activity (r2 = 0.73). The significantly lower correlation of the BT with vWF:RCo (r2 = 0.49) was particularly due to the poor results in vWD of type 2 (type 2:r2 = 0.29; types 1 and 3:r2 = 0.61). Finally, BT and IVBT-ADP correlated with each other (r2 = 0.53), a rather good correlation considering that both are complex functional tests. It can be concluded from our study that the IVBT not only may replace the BT for most applications, but is clearly superior to BT for the screening (IVBT-CaCl2) and control of therapy in vWD.

The frequency of heterozygous protein C and protein S deficiency, detected by measuring total plasma antigen, in a group (n = 141) of young unrelated patients (less than 45 years old) with venous thrombotic disease was studied and compared to that of antithrombin III, fibrinogen, and plasminogen deficiencies. Among 91 patients not receiving oral anticoagulants, six had low protein S antigen levels and one had a low protein C antigen level. Among 50 patients receiving oral anticoagulant therapy, abnormally low ratios of protein S or C to other vitamin K-dependent factors were presented by one patient for protein S and five for protein C. Thus, heterozygous Type I protein S deficiency appeared in seven of 141 patients (5%) and heterozygous Type I protein C deficiency in six of 141 patients (4%). Eleven of thirteen deficient patients had recurrent venous thrombosis. In this group of 141 patients, 1% had an identifiable fibrinogen abnormality, 2% a plasminogen abnormality, and 3% an antithrombin III deficiency. Thus, among the known plasma protein deficiencies associated with venous thrombosis, protein S and protein C deficiencies (9%) emerge as the leading identifiable associated abnormalities.

In a patient with deep venous thrombosis, plasma concentrations of coagulant and inhibitor proteins were normal except for moderate deficiency of plasminogen. Family studies revealed a similar deficiency in the mother and sister of the propositus. Evaluation of purified plasminogen demonstrated that it functioned normally. The patient represents our only example of plasminogen deficiency in 435 German individuals evaluated with a history of thromboembolism.

A new abnormal plasminogen, Frankfurt I, has been identified in the plasma of a 42 year-old male patient who has recurrent deep vein thrombosis. Clinical laboratory data showed normal hemostasis test results. Since plasma plasmin generation rates gave low values, the fibrinolytic system was analyzed for a possible fibrinolytic system defect. Functional and antigen plasminogen concentrations both in the plasma and with the isolated, purified plasminogen showed that only 49% of the antigen concentration had potential functional active sites. Also, a reduced antigen concentration was found in both the propositus, and his mother (46% active sites). Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the purified Frankfurt I plasminogen showed a normal native Glu-plasminogen band. Crossed-immunoelectrophoresis revealed a peak with normal size and shape, but displaced with respect to normal Glu-plasminogen toward the anode, i.e., was, as a whole, more negatively charged. Isoelectric focusing followed by zymography on a agarose-fibrin plate proved this observation, but did not indicate a separation of the normal from the abnormal plasminogen molecular species, also, fewer bands were found in the abnormal plasminogen isozyme pattern. Kinetic studies of Frankfurt I Glu-plasminogen and plasmin led to the conclusion that most of the functional abnormality is related to absence of active sites in half of the molecules. The plasmin generated was very unstable in the absence of stabilizing ligands and/or substrates. After reduction, the plasmin was completely converted to the typical two plasmin chains, A and B.