[Mixed nodular lymphoma in association with a C1 esterase inhibitor deficiency (author's transl)].
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Angioedema↗
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Results for “Complement C1”
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C1 inhibitor: the main inhibitor of human plasma kallikrein.
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Complement C1 Inactivator Proteins↗
[Deficiencies of C1 inhibitor: hereditary and acquired angioedema].
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Angioedema↗
[Hereditary angioedema: clinical and laboratory aspects of 7 cases].
Hereditary angioedema is caused by a defect in C1 inhibitor activity (C1INH). Its occurrence is rare and it is associated with an autosomal dominant mode of inheritance. We describe seven patients (4M:3F), age from 12 to 50 years old, who are affected by hereditary angioedema; four of them belong to the same family. The main clinical manifestations were: angioedema of face, hands and feet (6/7) and abdominal pain (2/7). No triggering factors were associated with symptoms in 4/7 patients and trauma (2/7) and menses (1/7) were reported in the other three ones. One patient was submitted to laparotomy for partial intestinal resection, before diagnosis. Laboratory complement analysis revealed the absence of hemolytic function of complement, reduced C4 (6/7) and low C1INH levels. All patients received Danazol (100 mg/day) with clinical control. Hereditary angioedema has to be considered in the differential diagnosis of angioedema, since an early diagnosis of this immunodeficiency, leading to specific treatment in order to decrease the complications.
Adult↗
The contact activation system: biochemistry and interactions of these surface-mediated defense reactions.
This review is intended to be a critical state-of-the-art overview of the activation and inhibition of the proteins (factor XII, prekallikrein, high molecular weight kininogen, and factor XI) of the contact phase of coagulation. Specifically, this review will reconsider the concept of the reciprocal activation of the proteases of the contact phase of coagulation, factor XII, and prekallikrein, in light of much recent evidence indicating that factor XII, itself, autoactivates when associated with negatively charged surfaces. In addition, the mechanisms for amplification of activation of the proteins of the contact phase of coagulation will be discussed from the pivotal role of high molecular weight kininogen, or one of its altered forms, serving as a cofactor to order the activation of the zymogens it is associated with. The role and relative importance of each of the naturally occurring plasma protease inhibitors (C1-inhibitor, alpha-2-macroglobulin, alpha-1-antitrypsin, antithrombin III, and alpha-1-antiplasmin) will be assessed as they relate to the dampening of contact phase activation. Finally, the contact phase of coagulation activation will be discussed not only as a plasma proteolytic mechanism, but also as it interacts with platelets.
Blood Coagulation↗
Emergency treatment of acute attacks in hereditary angioedema due to C1 inhibitor deficiency: what is the evidence?
Hereditary angioedema (HAE) is caused by a deficiency in C1 esterase-inhibitor (C1-INH) and is characterised by skin swelling, abdominal pain and episodes of upper respiratory tract obstruction. Oedema of the larynx can result in rapid asphyxiation and requires emergency treatment. Three treatment options for emergency treatment of HAE are reviewed: fresh frozen plasma, solvent/detergent-treated plasma and C1-INH concentrate. It is concluded that while all three treatment options are theoretically effective in the emergency treatment of HAE, C1-INH is the treatment of choice.
Acute Disease↗
[Functional determination of C1-inhibitors in human blood].
The author describes the method of assessment of the C1-inhibitor, the principle being activation of plasma prekallikrein by Hageman factor fragment (HFf) to the active enzyme kallikrein which splits the specific chromogenic substrate NO-Pro-Phe-Arg-pNA. In the presence of acetone the influence of C1-INH is eliminated and the assessed amount of kallikrein corresponds to the prekallikrein plasma level. In a parallel estimation without acetone after formation of the C1-INH complex the residual amount of kallikrein is assessed. The difference between the two levels is proportional to the formed enzyme-inhibitor complex. The method was tested on plasma of healthy donors and the results were compared with assessment of C1-INH by a modification of Schapira's method (6) (correlation coefficient r = 0.88) and with Cullmann's method (8) (r = 0.61). The advantage of the proposed method is that it does not require commercially unavailable enzyme preparations, that it uses as activating agent HFf concentrate, prepared in the laboratory and that along with the C1-INH level also the plasma level of prekallikrein is assessed.
Complement C1 Inactivator Proteins↗
[Molecular interaction between synthetic spirobutenolides and C1 esterase normal inhibitor].
Previously we have found that spirobutenolide synthetic derivatives show an inhibiting effect on C1 esterase activity. In contrast to these compounds some derivatives in the same series reveal an esterase activity when they are added to a C1 esterase preparation in presence of normal serum. The present work shows that this effect reflect an interaction with natural inhibitor C1 INH.
Complement C1 Inactivator Proteins↗
[Anomaly of the polypeptide and oligosaccharide chains of alpha-2-neuraminoglycoprotein in various types of hereditary angioneurotic edema].
Using two-dimensional immuno-electrophoresis to study a morphological abnormality of the alpha 2-neuramino-glycoprotein (alpha 2-NGP) we have been able to observe allelic exclusion in patients afflicted by hereditary angioneurotic oedema [1]. With the aid of two-dimensional immuno-affino-electrophoresis, we have been able to show that in some cases, there exists a double abnormality of alpha 2-NGP associating a deficiency in post translating glycosylation with a loss of the inhibitory function of the C1 esterase.
Angioedema↗
Reconstitution of C1 in native proenzyme form and its use in a quantitative C1 activation test.
C1 was reconstituted in macromolecular proenzyme, nonactivated form by incubation of highly purified C1q, C1r, and 125I-C1s together in the presence of calcium. C1 reformed in this manner had an equimolar ratio of C1 subcomponents, as is found in serum, and sedimented in sucrose density gradients with the 16S rate characteristic of C1 in serum. Reconstituted C1 was activatable as shown by cleavage of the 87,000 dalton polypeptide chain of C1s into disulfide linked subunits of 59,000 and 28,000 daltons, respectively, after incubation with aggregated IgG. The extent of activation may be quantitated. Reformed activatable proenzyme C1 can be used to quantitatively assess the C1-activating properties of various substances in addition to its use in the analysis of the C1 activation process.
Calcium↗
C1 inhibitor deficiency: consensus document.
We present a consensus document on the diagnosis and management of C1 inhibitor deficiency, a syndrome characterized clinically by recurrent episodes of angio-oedema. In hereditary angio-oedema, a rare autosomal dominant condition, C1 inhibitor function is reduced due to impaired transcription or production of non-functional protein. The diagnosis is confirmed by the presence of a low serum C4 and absent or greatly reduced C1 inhibitor level or function. The condition can cause fatal laryngeal oedema and features indistinguishable from gastrointestinal tract obstruction. Attacks can be precipitated by trauma, infection and other stimulants. Treatment is graded according to response and the clinical site of swelling. Acute treatment for severe attack is by infusion of C1 inhibitor concentrate and for minor attack attenuated androgens and/or tranexamic acid. Prophylactic treatment is by attenuated androgens and/or tranexamic acid. There are a number of new products in trial, including genetically engineered C1 esterase inhibitor, kallikrein inhibitor and bradykinin B2 receptor antagonist. Individual sections provide special advice with respect to diagnosis, management (prophylaxis and emergency care), special situations (childhood, pregnancy, contraception, travel and dental care) and service specification.
Adolescent↗
Anti-ischemia/reperfusion of C1 inhibitor in myocardial cell injury via regulation of local myocardial C3 activity.
C3 is common to all pathways of complement activation augmenting ischemia/reperfusion (I/R)-induced myocardial injury and cardiac dysfunction. Complement inhibition with the complement regulatory protein, C1 inhibitor (C1INH), obviously exerts cardioprotective effects. Here, we examine whether C1INH regulates C3 activity in the ischemic myocardial tissue. C1INH markedly suppressed C3 mRNA expression and protein synthesis in both a model of I/R-induced rat acute myocardial infarction (AMI) and the cultured rat H9c2 heart myocytes. At least, this regulation was at the transcriptional level in response to oxygen tension. In vitro, C3 deposition on, and binding to, the surface of rat myocardial cells were significantly blocked by C1INH treatment. C1INH could inhibit classical complement-mediated cell lysis via suppressing the biological activity of C3. Therefore, C1INH, in addition to inhibition of the systemic complement activation, prevents myocardial cell injury via a direct inhibitory role in the local myocardial C3 activity.
Animals↗
Binding of purified C1 subcomponents, C1 inactivator and their complexes to immobilized heparin.
Under specified conditions purified C1q, activated C1r and C1s and C1r-C1s complexes were bound independently of Ca2+, to heparin-Sepharose, and could be eluted by an increasing salt gradient. Zymogen C1r and C1s, C1r-C1s complexes, C1 inactivator, and C1r-C1s-C1 activator complexes were not bound. However, at lower conductance Ca2+ independent binding of C14 occurred, which was utilized in the purification of C14 and C1s. In the presence of C1t (serum amyloid P component), C1s was firmly retained on heparin-Sepharose, which was probably due to formation of a C1s-C1t complex.
Amyloid↗
The first component of complement as a constituent of human salivary sediment.
The sediment from human saliva is complement-reactive. Evidence presented shows that C1 (first component of complement) is a constituent of sediment from healthy human donors. Sediment (Sed) inactivated functionally pure C4 (fourth component of complement), and this action on C4 was inhibited by EDTA, phenylmethylsulphonylfluoride (PMSF, a serine-esterase inhibitor) and C1-inhibitor (C1-In). When Sed was incubated with 0.15 ionic strength buffer and separated by centrifugation, C1 haemolytic activity was found in the supernatant. By incubating Sed with EAC4 cells (sheep erythrocytes sensitized with rabbit antibody to which C4 has been fixed), transfer was shown of C1 from the Sed to the cells, resulting in the formation of EAC14; this transfer was inhibited by IgG directed against a subunit of C1 (anti-C1s).
Adult↗
Evaluation of euglobulin methods for the study of blood fibrinolytic activity: results for patients with rheumatoid arthritis and in the postoperative period.
Euglobulin fractionation is a frequently employed pretreatment of plasma for the determination of fibrinolytic activity. The fractionation procedure suffers from possible in vitro artifacts, e.g., variable precipitation of C1-inactivator. This is illustrated by the following two situations. It is shown that increased amounts of C1-inactivator not related to an increased plasma concentration are present in euglobulin fractions in cases of classic rheumatoid arthritis. Similarly, postoperatively, a disproportional increase in C1-inactivator in euglobulin fractions occurs. In both cases, an artificially reduced fibrinolytic activity is recorded due to increased inhibition by C1-inactivator. This is circumvented and recognized by adding sodium flufenamate or C1s-esterase to euglobulin fractions to uniformly eliminate C1-inactivator. Two specific assays for tissue-type plasminogen activator activity in euglobulin fractions (as C1-inactivator-resistant activator activity and a parabolic rate assay on a synthetic substrate) correlate excellently (r = 0.8728; p less than 0.001; n = 108). The first mentioned is corrected for variable endogenous C1-inactivator; the latter assay is found to be insensitive to inhibition by C1-inactivator. It is concluded that with euglobulin methods a misinterpretation of blood fibrinolytic activity is possible in rheumatoid arthritis patients. In the postoperative period, the fibrinolytic shutdown concerns tissue-type plasminogen activator activity; the pattern of the shutdown can be misjudged in using traditional euglobulin methods.
Abdomen↗
Complement components required for virus neutralization by early immunoglobulin antibody.
Virus neutralization by early antisera usually requires or is enhanced by the presence of complement. The particular components of the complement system which are needed for neutralization of Newcastle disease virus by early IgM antibodies were studied. It was found in this system that participation of only the first four of the nine complement components (C1, C2, C3, and C4) was necessary and sufficient for neutralization to occur. It was concluded that the role of complement in neutralization was most likely that of contributing bulk in the form of large protein molecules to the virus-antibody complex.
Animals↗
A newly described control mechanism of complement activation in patients with mixed cryoglobulinemia (cryoglobulins and complement).
Levels in serum of components of complement were studied in a group of 10 patients with mixed cryoglobulinemia. The profiles found in most patients showed decreased levels of the early complement components C1, C4, and C2, with normal levels of C3. Experiments performed to define the mechanism(s) responsible for this unusual complement profile showed that activation of the early complement components in serum was due to the activation of the classical pathway by mixed cryoglobulins. They also showed that the characteristic lack of effect on C3 was due to the action of a previously unrecognized regulatory mechanism upon C3 convertase of the classical pathway mediated by 2 normal serum proteins, namely, the C4 binding protein (C4-bp) and the C3b inactivator (C3bINA).
Complement Activating Enzymes↗
Activation of the alternative pathway of complement by human peripheral nerve myelin.
Destruction of peripheral nerve myelin (PNM) occurs as a consequence of a variety of pathologic conditions affecting the peripheral nervous system. In certain primary demyelinating neuropathies, several lines of evidence implicate complement in the pathogenesis of demyelination. In this study we demonstrate that human PNM consumes complement in vitro in the absence of specific antibody or C1 activation. Furthermore, activation of complement by PNM via the alternative pathway was shown by cleavage of C3 in normal human serum (NHS) and of B in C2-deficient serum (C2d-HS). Increasing consumption of hemolytic activity of C3 in Mg-EGTA-treated NHS was also noted with increasing amounts of PNM. Pronase treatment of PNM abolished C3 consumption, suggesting that a protein component exposed on the surface of myelin participated in the alternative pathway activation. When P0, the major amphiphilic glycoprotein of PNM, was incorporated into artificial lipid bilayers, the Po-liposomes consumed C3 activity in NHS containing Mg-EGTA. Pronase treatment of Po-liposomes abolished C3 consumption to the level of control liposomes, indicating that P0 was responsible for at least part of the activation seen with peripheral myelin.
Animals↗