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PubMedDate not supplied

Complement consumption and IgE binding by house dust allergen in the serum of atopic patients.

The reactivity of complement (C) with housedust allergen has been investigated in separate groups of sera from atopic patients with seasonal hay fever, bronchial asthma, atopic dermatitis, animal dander allergy or asthmatic bronchitis as compared to controls. Complement consumption was more pronounced on average in the allergy groups, with the exception of atopic dermatitis. Total IgE levels were elevated in all groups, especially in atopic dermatitis. There was no correlation between C-sensitivity and IgE data (RAST and RIST). The mean levels of C1-inhibitor, 1-antitrypsin and 2-marcroglobulin in the atopic group were found normal. A significant correlation was found between the extent of C-consumption by house dust allergen and the level of C4 in sera. It is concluded that both C and IgE differ from normal in atopic patients, but that neither one is suited for the routine diagnosis of atopy in individual serum samples.

Adult↗
PubMed2005

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↗
PubMed1992

A novel sensitive assay for functional factor XII based on the generation of kallikrein-C1-inhibitor complexes in factor XII-deficient plasma by glass-bound factor XII.

We developed a very sensitive assay for functional factor XII. This assay is based on the property of glass-bound factor XII to activate prekallikrein (PK) into kallikrein in factor XII-deficient plasma, which is assessed by measuring the formation of kallikrein-C1-inhibitor complexes in this plasma by radioimmunoassay. Incubation of varying amounts of factor XII in glass tubes led to a dose-dependent increase in kallikrein-C1-inhibitor complexes in factor XII-deficient plasma with a lower limit of detection of +/- 20 pg of factor XII. The specificity of the assay for factor XII was demonstrated by experiments with plasmas deficient for factor XII, PK or high molecular weight kininogen (HK) and by incubation of factor XII with Polybrene or with a monoclonal antibody that inhibits the amidolytic and procoagulant activity of factor XII. The high sensitivity of the assay appeared to be due to the inability of C1-inhibitor to inhibit factor XII bound to glass, which resulted in a molar ratio of generated kallikrein to glass-bound factor XII of at least 100:1. This assay for factor XII may be a feasible tool in studies on structural and functional aspects of (recombinant) factor XII species synthesized by cultured cells.

Complement C1 Inactivator Proteins↗
PubMed1980

Human seminal plasma inhibition of complement.

Recent studies have shown that human seminal plasma contains chemically and biologically distinct factors which inhibit lymphocyte functions and the serum bactericidal and opsonic activities associated with the killing of gram-negative organisms. Because of the direct association between complement action and serum bactericidal and opsonic activities, inhibition of complement may be one of the possible mechanisms of action of seminal plasma immunoinhibitory factors. Complement hemolytic activity was measured for C3 and C4 in serum Neisseria gonorrhoeae and Escherichia coli bactericidal reaction mixtures with and without addition of seminal plasma. In the presence of seminal plasma, where there was no bactericidal action, C3 and titers were reduced to approximately 50% of the titers in the reactions with complement donor serum. The C3 titers were lower than in the reaction mixtures with immune serum and complement donor serum, where N. gonorrhoeae bactericidal activity occurred. Individual human seminal plasma specimens depressed CH50 activity of pooled normal human sera up to 50% of normal levels. There were no differences in inhibition by seminal plasma specimens from normal or vasectomized men. Treatment with seminal plasma depressed the functional activity of complement components C1 and C3 by more than 50%. Seminal plasma also inhibited alternate pathway activity. Cleavage of factor B was demonstrated. The seminal plasma factor which inhibited complement was of low molecular weight. DPF blocked the seminal plasma complement-inhibitory factor. However, amidolytic activity for serine protease substrates could not be demonstrated. It is likely that the seminal plasma complement inhibitor is a protease inhibitor acting singly or in combination.

Absorption↗
PubMed1976

Occurrence of C1 inactivator and other proteinase inhibitors in euglobulin fractions and their influence on fibrinolytic activity.

Considerable amounts of C1 inactivator and inter-alpha-trypsin inhibitor pecipitate during euglobulin fractionation of human plasma. The amount precipitated depends on the ionic strength and the pH during the fractionation procedure. In contrast, alpha1-anti-trypsin, alpha2-macroglobulinand antithrombin II are present in euglobulin fractions in trace amounts only. The fibrinolytic activity of the euglobulin fractions is inhibited by the endogenous C1 inactivator, particularly as shown by comparison of normal and hereditary angioneurotic edema (HANE) plasma.

Angioedema↗
PubMed1991

Complement activation during bypass in acquired C1 esterase inhibitor deficiency.

Serial complement estimations during cardiopulmonary bypass are reported in a patient with acquired C1 esterase inhibitor deficiency. Although the extent of classic and alternative pathway activation appeared appropriate, exaggerated common pathway activation with massive increase in the C3d:C3 ratio occurred. A fatal hemostatic disorder, pulmonary edema, and circulatory collapse ensued despite prophylaxis and therapy.

Aged↗
PubMed1980

Purified proenzyme C1r. Some characteristics of its activation and subsequent proteolytic cleavage.

1. Upon incubation for 1 h at 37 degrees C, proenzymic C1r was activated by a proteolytic cleavage comparable to that observed in vivo; after reduction and alkylation, two fragments of apparent molecular weights 57 000 and 35 000 were evident on sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. The activation kinetics were slightly sigmoidal and nearly independent of C1r concentration. They were characterized by a marked thermal dependence (activation energy = 45 kcal/mol). The reaction was inhibited by calcium and p-nitrophenyl-p'-guanidinobenzoate, but poorly sensitive to di-isopropyl phosphorofluoridate. The dependence of the activation rate on pH was unusual; it decreased progressively in the acid range (pH 4.5-6.5) which coincides with the dissociation of the C1r-C1r dimer. Above pH 6.5, the rate increased slightly and showed no clear maximum. These results are consistent with an intramolecular autocatalytic activation mechanism involving the pro-site of each subunit of the C1r-C1r dimer. 2. During a 5 h incubation period at 37 degrees C, C1r underwent two proteolytic cleavages which led to the successive removal of two fragments, alpha (35 000) and beta (7000-11 000) from each subunit, leaving a dimeric molecule of reduced size (Mr = 110 000; s20,w = 6.1 S). The proteolytic process was nearly independent of C1r concentration and characterized by a pH optimum at 8.5-9.0, and a high activation energy (36.8 kcal/mol). Calcium and p-nitrophenyl-p'-guanidinobenzoate, and also di-isopropyl phosphorofluoridate and benzamidine were inhibitors of this reaction. The product, C1r II, retained the original antigenic properties of C1r and a functional active site, but lost the capacity to bind C1s. These results are consistent with an autocatalytic intramolecular proteolysis mediated by the active site of each subunit of the C1r-C1r dimer.

Complement Activating Enzymes↗
PubMed1978

[The molecular expression of C1 esterase inhibitor in hereditary angioneurotic oedema. Study of 32 families (author's transl)].

Seventy seven patients from 32 families suffereing from angioneurotic oedema were studied and a single theory of the disorder is suggested. The functional abnormality of alpha2 neuraminoglycoprotein (NGP) or of C1 esterase inhibitor is related involvement of the structure gene (s) controlling its synthesis. Particular immunochemical characteristics of the inhibitor seen in severals families and remaining constant through a number of generations would indicate the existence of a phenomenon of functional haploidism in these heterozygous patients. Treatment of the condition with androgens suggests the existence of two varieties of alpha2 NGP molecules which are differentiated on the basis of their complete or incomplete glycoconjugation in the hepatocyte.

Androgens↗
PubMed1992

Peripheral edema due to increased vascular permeability: a clinical appraisal.

The release of vasoactive substances produces reversible changes of endothelial permeability with consequent edematous syndromes. We present 899 patients referred to our clinic for "non-hydrostatic non-hyponcotic" recurrent edema problems. Personal and family histories were recorded and a complete physical examination was carried out for each patient. In chronic situations laboratory tests [blood cell count, cryoglobulins, thyroid hormones, complement components (C3, C4, C1 inhibitor), total IgE, skin testing] were performed. Four subgroups of angioedema are identified for relevant clinical and etiopathogenetic differences. Seventy-three percent of patients had an urticaria-angioedema syndrome responding to antihistamine and/or corticosteroid treatment (histamine-dependent angioedema). Twenty-three percent had an angioedema related to a deficiency in C1 esterase inhibitor (complement-dependent angioedema). In a minority of patients, angioedema was due to the pharmacological effect of a drug (pharmacological angioedema) or was of a totally unknown origin (idiopathic angioedema). A generalized increase in vascular permeability was reported in 3 patients (systemic capillary leak syndrome). A brief survey of the literature is given with the review of our patients.

Adolescent↗
PubMed1991

C1 esterase inhibitor deficiency: three presentations.

We have presented three patients representing three of the four reported forms of C1 esterase inhibitor deficiency. The C1INH deficiencies are in general distinguishable from each other and from other forms of angioedema by their complement patterns. The acquired C1INH deficiency must be part of the differential in patients without a family history of angioedema since it may precede the diagnosis of more serious medical conditions such as lymphoproliferative disorders.

Adolescent↗
PubMed1986

[Immunocytoma with acquired C1-esterase inhibitor deficiency and recurrent angioneurotic edema].

Four attacks of mucosal angioneurotic oedema occurred in a 57-year-old woman, requiring tracheotomy for one episode. Decreased or non-measurable levels of complement components C1q, C-1-INH and C4 pointed to a complement consumption. The basic disease was a pleomorphic immunocytoma with the production of monoclonal IgM. Treatment with danazol, 600 mg daily, raised the serum level of C-1-INH, but not of C4.

Angioedema↗
PubMed1999

Acquired C1 inhibitor deficiency associated with systemic lupus erythematosus, secondary antiphospholipid syndrome and IgM monoclonal paraproteinaemia.

In this case report, a woman is described who developed systemic lupus erythematosus at the age of 36 years affecting the central nervous system and kidneys, showing the serological evidence of an acquired C1 inhibitor deficiency, but also developing an antiphospholipid syndrome and IgM lambda type paraproteinemia. During the 25 years follow-up she did not show any signs of angioedema. Although the immunological abnormalities are still constantly present, the disease has been quiescent since the past three years. The possible pathophysiology of clinical and laboratory features are discussed.

Antibodies, Anticardiolipin↗
PubMed1997

Heparin coating of extracorporeal circuits inhibits contact activation during cardiac operations.

OBJECTIVE: Heparin coating reduces complement activation on the surface of extracorporeal circuits. In this study we investigated its effect on activation of the contact system in 30 patients undergoing coronary artery bypass grafting with the use of a heparin-coated (Duraflo II, Baxter Healthcare Corp., Edwards Division, Santa Ana, Calif.; n = 15) or an uncoated extracorporeal circuit (n = 15). METHODS: Plasma markers that reflect activation of contact (kallikrein-C1-inhibitor complexes), coagulation (prothrombin fragments F1 + 2), or fibrinolytic (plasmin-alpha 2-antiplasmin complexes) systems were determined before and during the operation. The generation of kallikrein-C1-inhibitor complexes was reduced by 62% (p = 0.06) after the onset of cardiopulmonary bypass and by 43% (p = 0.026) after the cessation of bypass in the group in which a heparin-coated circuit was used compared with the group in which the circuit was uncoated. Generation was reduced by 58% (p = 0.06) when the ratio of kallikrein-C1-inhibitor to prekallikrein after onset of bypass was considered. We detected significant increases in F1 + 2 levels in both groups and increases in plasmin-alpha 2-antiplasmin complexes in the heparin-coated group at cessation of bypass, but no intergroup differences were observed. Thus use of heparin-coated extracorporeal circuits during cardiac operations reduces formation of kallikrein-C1-inhibitor complexes when compared with use of uncoated circuits. The heparin coating is not accompanied by similar reductions in coagulation or fibrinolysis, suggesting that thrombin and plasmin formation during cardiopulmonary bypass occurs mainly independently of the contact system activation.

Aged↗
PubMed1993

[C1-inhibitor plasma levels in neonates and mothers during labor].

The authors investigated C1-inhibitor (C1-INH) plasma levels in blood collected from mothers during delivery: mothers with a normal pregnancy and a group of mothers who displayed during the perinatal period direct or indirect signs of infectious disease. Both groups, as compared with a group of healthy donors, had low C1-INH levels. The neonates were divided into two groups (normal children and children with perinatal risk of infection) with sub-groups of mature full-term neonates (38-41 weeks of gestation) and premature infants (29-36 weeks of gestation). In the group of normal infants the neonates had on average somewhat lower C1-INH levels, as compared with healthy donors, in premature neonates of this group the lowest mean C1-INH level was recorded. In this group the authors observed a correlation between the inhibitor level and the gestation period. The results of C1-INH assessment in the group of neonates with a perinatal risk of infection were different. In premature neonates a higher average C1-INH level was observed than in mature neonates and the relationship between the C1-INH level and the gestation period was a linear negative regression. The postnatal increase of C1-INH levels on the 1st to 5th day was more rapid in premature neonates of both groups.

Complement C1 Inactivator Proteins↗
PubMed1985

Plasma total prekallikrein/kallikrein activity in rheumatoid arthritis with and without amyloidosis. Increased kaolin-stimulated activity in patients with amyloidosis.

Following exposure to kaolin, plasma samples were assayed for total prekallikrein/kallikrein activity in 19 patients with rheumatoid arthritis (RA), 39 patients with RA complicated by amyloidosis, 13 patients with nonamyloid nephropathy and 54 healthy subjects. Increased total kallikrein activity was found in RA patients with amyloidosis and in patients with nonamyloid nephropathy. The concentrations of the plasma kallikrein inhibitors C1-inactivator and alpha 2-macroglobulin were normal in RA patients without amyloidosis, whereas they were increased in patients with amyloidosis as well as in patients with nonamyloid nephropathy. The results suggest that the increased activity of plasma kaolin-stimulated kallikrein in RA patients with amyloidosis is due to the nephropathy per se and probably reflects increased levels of prekallikrein.

Adult↗
PubMed1992

Angioedema and C1 inhibitor deficiency.

Deficiency of C1 inhibitor resulting in episodes of angioedema causes significant morbidity and mortality in affected patients, yet often goes undiagnosed for years. As biochemical understanding of the disorder has improved, competing theories for the pathophysiologic mechanism of angioedema have emerged. Further, existing therapeutic interventions have been refined by experience and newer modalities currently available in Europe may soon become available in the United States.

Angioedema↗
PubMed1986

C1 esterase inhibitor deficiency in X-linked hypogammaglobulinaemia: an anomaly fostering anaphylactoid reactions following intramuscular gammaglobulin administration.

A patient with apparent X-linked agammaglobulinaemia was found to be inordinately susceptible to anaphylactoid reactions to intramuscular injections of gammaglobulin. The patient was found also to have low levels of C1 esterase inhibitor (C1 INH). The possibility that the C1 INH deficiency and in this patient, whether genetic or acquired, fostered the susceptibility to the production of anaphylactoid reactions after gammaglobulin injections urges further studies of the association of C1 INH deficiency and anaphylactoid reactions to gammaglobulin injections. The possibility that C1 INH levels like C1q levels may be low in hypogammaglobulinaemic patients as a consequence of increased catabolism of this regulator of the complement system when IgG levels are low is considered.

Adult↗
PubMed1991

Characterization of C1 inhibitor binding to neutrophils.

In a previous study we have isolated neutrophil membrane proteins that non-covalently bind to native C1-INH (105,000 MW) and a non-functional, degraded C1-INH (88,000 MW; C1-INH-88). To further characterize the binding nature, we have designed a novel kinetic C1 titration assay which enables not only a quantification of the removal of fluid-phase C1-INH by neutrophils, but also a concomitant measure of residual C1-INH function. Native C1-INH, when adsorbed to EDTA-pretreated neutrophils, lost its function in the inhibition of fluid-phase C1. The non-functional C1-INH-88, which is probably devoid of a reactive centre, was found to block the binding of native C1-INH to neutrophils. Pretreatment of neutrophils with serine esterase inhibitors did not abrogate binding capacity of the cells for C1-INH, whereas the binding affinity for C1-INH was lost when the cells were pretreated with trypsin. An array of human peripheral blood leucocytes and several lymphoid cell lines has surface binding sites for C1-INH, but not on human erythrocytes and U937 cells. Binding was further confirmed using (i) C1-INH-microsphere beads to neutrophils, in which the binding was blocked when pretreating neutrophils with excess C1-INH or with trypsin, and (ii) radiolabelled C1-INH to neutrophils, which was competitively blocked by unlabelled non-functional C1-INH-88. Desialylation of C1-INH significantly reduced its binding affinity for neutrophils, indicating that the membrane receptor sites on neutrophils could be specific for the binding of sialic acid residues on C1-INH. Overall, our studies indicate that neutrophils or other leucocytes possess specific surface binding sites for the sialic acid-containing portion of C1-INH.

Binding, Competitive↗