Fibrinogen Cleveland II. An abnormal fibrinogen with defective release of fibrinopeptide A

Fibrinogen Denver: a dysfibrinogenemia associated with an abnormal Reptilase time and significant bleeding

This paper reports a new dysfibrinogenemia with an unusual pattern of laboratory assays. The patient, a 51-year-old female with a lifelong moderate bleeding history, was initially diagnosed with von Willebrand disease based on routine coagulation assays and the clinical bleeding presentation. During recent testing as part of a preoperative screen and without any current history of treatment, levels of von Willebrand factor (VWF) antigen, VWF activity, and factor VIII activity were all significantly elevated, which was unexpected given her previous diagnosis. Additional testing was performed looking for other heritable causes for her considerable bleeding tendency. Interestingly, the patient had a significantly prolonged Reptilase time, minimally short thrombin time, and an abnormal fibrinogen-crossed immunoelectrophoresis pattern. Clearly, this patient had a fibrinogen abnormality that had been missed when only routine coagulation screening assays were performed. A brief review of the fibrinogen literature revealed no other dysfibrinogenemias reported with a similar pattern of test results, and thus this defect was designated fibrinogen Denver.

Fibrinogen Guarenas I: partial characterization of a new dysfibrinogenemia with an altered rate of fibrinopeptide release and an impaired polymerization

A congenitally abnormal fibrinogen was isolated from the blood of a young woman with a severe bleeding diathesis. Coagulation tests showed a prolonged Thrombin and Reptilase time partially corrected by Ca2+. Polymerization of thrombin induced preformed fibrin monomers was severely impaired. Thrombin caused the release of fibrinopeptides with normal retention times on HPLC. However, the rate of release was abnormally slow and the total amount of fibrinopeptide A (FpA) released reached only approximately 50% of the theoretical maximum. The rate and quantity of FpA release was normal when Reptilase was used. Transmission Electron Microscopy (TEM) of Thrombin induced clots showed an altered clot structure characterized by a reduced mean fiber diameter. The mother has a polymerization defect similar to the propositus, her fibrinopeptide release is unaffected however. The father has a minor fibrinopeptide release defect suggesting the presence of two populations of fibrinogen. This study supports the idea that the fibrinogen isolated from the propositus has two defects inherited as separate genetic traits. This fibrinogen has been named Fibrinogen Guarenas I.

Spontaneous reversal of acquired autoimmune dysfibrinogenemia probably due to an antiidiotypic antibody directed to an interspecies cross-reactive idiotype expressed on antifibrinogen antibodies

A young man with a long history of abnormal bleeding was seen in January 1985. Coagulation tests showed dysfibrinogenemia and an antifibrinogen autoantibody was demonstrable in his serum. This antibody, when purified, was capable of inhibiting the polymerization of normal fibrin monomers, apparently through binding to the alpha fibrinogen chain. 6 mo later the patient was asymptomatic, coagulation tests were normal, and the antifibrinogen autoantibody was barely detectable. At this time, affinity-purified autologous and rabbit antifibrinogen antibodies were capable of absorbing an IgG kappa antibody from the patient's serum, which reacted indistinctly with both autologous and xenogeneic antifibrinogen antibodies in enzyme immunoassays. It has been concluded that the patient's dysfibrinogenemia was the result of an antifibrinogen autoantibody, and that later on an anti-idiotype antibody, which binds an interspecies cross-reactive idiotype expressed on anti-human fibrinogen antibodies, inhibited the production of the antifibrinogen autoantibody which led to the remission of the disorder.

Hemophilia B (Christmas disease) variants and carrier detection analyzed by DNA probes

We have used two strategies to study 14 hemophilia B families from 11 kindreds for possible carrier detection and prenatal diagnosis. First, we sequentially used the Factor IX probes (sequentially with restriction enzymes Taq I, Xmn I, and Dde I), and the linked probes p45h (Taq I), p45d (Pst I), and 52a (Taq I) for restriction fragment length polymorphism (RFLP) analysis. Second, we searched for useful variant Taq I digestion fragments using the Factor IX complementary DNA. Two separate new Taq I variants in exon VIII were identified. Using both strategies, 11 of 14 families (from 9 of 11 kindreds) were informative for further studies. In five kindreds studied in detail, the carrier status of all 11 at risk females was determined and prenatal diagnosis could be offered to the offsprings of each of the six carriers identified. Thus, in this study, we have identified a higher proportion of informative families than has previously been reported.

Studies on a family with combined functional deficiencies of vitamin K-dependent coagulation factors

Two siblings with m ild hemorrhagic symptoms had combined functional deficiencies of vitamin K-dependent clotting factors. Prothrombin (0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) were most severely affected. Antigenic amounts of affected coagulation factors were normal and normal generation of thrombin activity occurred in the patients' plasmas after treatment with nonophysiologic activators that do not require calcium for prothrombin activation. Hepatobilary disease, malabsorptive disorders, and plasma warfarin were not present. Both parents had normal levels of all coagulation factors. The patients' plasmas contained prothrombin that reacted both with antibody directed against des-gamma-carboxyprothrombin and native prothrombin. Crossed immunoelectrophoresis of patients' plasmas and studies of partially purified patient prothrombin suggested the presence of a relatively homogeneous species of dysfunctional prothrombin, distinct from the heterologous species found in the plasma of warfarin-treated persons. These studies are most consistent with a posttranslational defect in hepatic carboxylation of vitamin K-dependent factors. This kindred uniquely possesses an autosomal recessive disorder of vitamin K-dependent factor formation that causes production of an apparently homogeneous species of dysfunctional prothrombin; the functional deficiencies in clotting factors are totally corrected by oral or parenteral administration of vitamin K1.

Labile anticoagulant in a patient with lymphoma

A patient with diffuse lymphocytic lymphoma and monoclonal IgM kappa immunoglobulin was found to have an unstable circulating anticoagulant. The anticoagulant inhibited phospholipid-dependent plasma coagulation reactions. Unlike previously described anticoagulants of this type, this plasma inhibitor was neutralized in vitro by products of platelet lysis but not by exogenous addition of other phospholipids or by intact platelets. Inhibitory activity seemed dependent on the monoclonal immunoglobulin, but isolated immunoglobulin fractions lacked anticoagulant activity, suggesting that the inhibitory function was dependent on an easily disrupted macromolecular aggregate. Recognition and characterization of other similar anticoagulants may provide a means of studying the role of phospholipids in normal hemostasis.

Fibrinogen Houston: a dysfibrinogen exhibiting defective fibrin monomer aggregation and alpha-chain cross-linkages

A 38-year-old male patient with a life-long history of easy bruising and mild bleeding had a prolonged activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). Reptilase (Bathrops atrox) clotting time was normal. His undiluted and diluted plasma prolonged the APTT, PT, and TT of normal plasma. Fibrin produced from patient plasma was insoluble in 5 M urea. Plasma fibrinogen level was increased when measured as clottable protein and by Laurell electroimmunoassay. Specific assays of plasma factors II, V, VII, X, VIII, IX, XI, and XII were normal. A circulating antithrombin in patient plasma was excluded by demonstrating normal thrombin-induced platelet aggregation of gel-separated platelets in the presence of patient plasma. Purified patient fibrinogen reproduced the anticoagulant effect of patient plasma. Patient fibrinogen antigen was similar to normal fibrinogen antigen by immunodiffusion, immunoelectrophoresis (pH 5.2 and 8.6), and crossed immunoelectrophoresis. His unreduced purified fibrinogen had normal migration on polyacrylamide slab gels. Also, the migration in gel slabs of A alpha, B beta and gamma-polypeptide chains, produced by mercaptoethanol reduction of purified patient fibrinogen, was similar to reduced normal fibrinogen. Thrombin-induced total fibrinopeptide release was normal. However, fibrin monomers produced from patient fibrinogen by thrombin (devoid of fibrinopeptides A and B) reaggregated abnormally; fibrin monomers produced by reptilase (devoid of only fibrinopeptides A) reaggregated normally. Fibrin generated from patient plasma in the presence of factor XIII and calcium, was defective in the formation of covalently bonded alpha-alpha polymers and demonstrated an increased susceptibility to the lytic effects of plasmin (generated in vitro by the addition of streptokinase).

[Dysfibrinogenemia. A new case: dysfibrinogenemia Giessen III (author's transl)]

A new case of dysfibrinogenemia is reported which shows no signs of a haermorrhagic diathesis (dysfibrinogenemia Giessen III). The abnormal fibrinogen was detected by only slight but characteristic alterations of some parameter of the coagulation analysis (prolonged clotting times after addition of thrombin, Reptilase and thrombin coagulase; low fibrinogen concentration determined by methods based on clot formation in comparison to the immunological fibrinogen determination; delayed fibrin polymerization). In addition, clinical features and diagnosis of dysfibrinogenemia are described in general.

Fibrinogen Marburg a new genetic variant of fibrinogen

A new case of congenital dysfibrinogenemia has been discovered in a 20 year old woman, who suffered from a severe postpartal hemorrhage after the delivery of her first child, followed by episodes of thrombosis. Coagulation studies reveal a prolongation of thrombin time, reptilase time was immeasurable. Thromboplastin time and partial thromboplastin time were slightly prolonged. Low fibrinogen levels were obtained by techniques, which depend on the coagulation velocity following addition of thrombin, while immunological procedures gave slightly diminished values of fibrinogen. Patients's fibrinogen had a moderate inhibitory effect on the fibrin formation in normal plasma. However, inhibitors of the fibrinogen-fibrin conversion could not be detected. Coagulation factors were normal, fibriolysis as well. The cause of the coagulation disorder was found to be a defect of the fibrinogen molecule, leading to an abnormal fibrin polmerization of patient's fibrin monomers. The release of the fibrinopeptides in the paperelectrophoresis was normal. The defect of the fibrinogen molecule did not protect from thrombotic complications. The same defect could be found in the lower scale in patient's father, 4 of her 7 brothers and sisters, and her son.

[Fibrinogen "Hannover", a further abnormal fibrinogen]

Another abnormal fibrinogen--"fibrinogen Hannover"--is reported. As known from most dysfibrinogenemias the clottability is poor, while immunologic test, heat precipitating test and the staphylococcal clumping test give normal fibrinogen concentrations. The clotting time when using thrombin or thrombin like enzymes is prolonged, it can be corrected with high thrombin concentration or thrombin combined with calcium inons, but not with thrombin like enzymes combined with calcium ions. The mild bleeding diathesis was first noted when the patient underwent an operation.