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PubMed1987

Serum concentrations of immunoglobulins and complement components in women using an intra-uterine contraceptive device (IUCD).

Immunoglobulins A, G and M and the complement components C3, C4 and CI-INH were quantified in sera from 59 women using an intra-uterine contraceptive device (IUCD). Most of the women were using a Cu IUCD, and the mean duration of use was 7.3 years. No differences in the concentrations were detected compared with control subjects. Our data, however, do not exclude a possible temporary change in the concentrations of immunoglobulins and complement components.

Adult↗
PubMed1993

The contact system in human malignant and benign ascites.

The plasma contact system was studied in ascites and plasma from patients with gastrointestinal cancer and patients with liver failure. Our study demonstrates the presence of factor XII, factor XI, and prekallikrein and their main inhibitors in ascites and plasma from both patient groups. Both factor XII-like and plasma kallikrein-like activities were detected in the malignant ascites. The kallikrein-like activity in malignant ascites was found in complex with alpha 2-macroglobulin. In plasma samples from the patients functional values of factor XII and prekallikrein were decreased compared to controls. In benign ascites the proenzyme levels were significantly lower than in malignant ascites. Functional inhibition values in ascites and plasma from patients were unexpectedly high. Our findings indicate that the plasma contact system is activated in the ascites from cancer patients. Activation of the contact system generates vasoactive mediators, which may play a role in the accumulation of malignant ascites.

Aged↗
PubMed1980

The complement system in uremia.

Plasma C1q, C1 esterase inactivator, C4, C3 and C3 proactivator were measured in 20 chronic uremic patients on maintenance hemodialysis, in 10 conservatively treated chronic uremic patients and in 20 healthy volunteers. There was no statistical significant difference between the patient groups in any of the measured complement components. The C1q, C1 esterase inactivator and C4 concentration were found to be the same in the patient and the control groups. The C3 and C3 proactivator levels were equally and significantly lower in both patient groups compared with the healthy volunteers.

Adolescent↗
PubMed1980

Different serum requirements for opsonization of two serologically identical strains of Pseudomonas aeruginosa.

Two strains of serotype 2 Pseudomonas aeruginosa and one species of E. coli were compared regarding their opsonic requirements using human sera and polymorphonuclear leukocytes. None of the three organisms tested activated exclusively one complement pathway. Both strains of Pseudomonas had an absolute requirement for antibody for opsonization, but differed in complement requirements. The studies described herein showed significant differences in the mechanism of opsonization of the two strains of Pseudomonas.

Binding Sites, Antibody↗
PubMed1991

C1 inhibitor: different mechanisms of reaction with complement component C1 and C1s.

Inactivation of human complement subcomponent C1-s by its regulator C1 inhibitor at physiological ionic strength proceeded at a 3-fold higher rate when C1-s was in the physiological C1- complex with subcomponents C1q and C1-r rather than as purified subunit. When the C1- complex was disassembled by chelation of calcium, the C1-s subcomponent was inactivated by C1 inhibitor at rates similar to those for the purified proteinase. Increasing ionic strength had little effect on the reaction of purified C1-s with C1 inhibitor but greatly diminished the rate of reaction of intact C1-. Addition of heparin accelerated the inactivation of purified C1-s by C1 inhibitor up to 25-fold but increased the inactivation of intact C1- only about 5-fold. These differences in the inactivation of C1-s by C1 inhibitor, depending on whether the proteinase is free or complexed with other subcomponents of C1-, suggest different mechanisms of reaction. Occurrence of subcomponent C1-s in a macromolecular complex with C1q and C1-r, thus, appears to be critical not only for directing its physiological activation but also its inactivation.

Complement C1↗
PubMed1999

Coincidence of hereditary angioedema (HAE) with Crohn's disease.

A patient with two diseases, based presumably on different immunopathological mechanisms, hereditary angioedema (HAE) and Crohn's disease, was followed for 8 years. For more than three years of this observation period, detailed laboratory data were also available and could be analyzed. Both diseases had severe courses requiring chronic treatment with danazol and sulfasalazine, respectively. During exacerbation of Crohn's disease, the levels of C4 was found to be significantly lower than during the periods free of symptoms of both diseases. This drop was probably due to an impaired C1-inhibitor activity. HAE attacks and acute exacerbation of Crohn's disease never occurred simultaneously. This finding may be a mere chance but may also indicate that the different immunopathological processes underlying HAE and Crohn's disease influence each other.

Adult↗
PubMed2000

The Arthus reaction in rodents: species-specific requirement of complement.

We induced reverse passive Arthus (RPA) reactions in the skin of rodents and found that the contribution of complement to immune complex-mediated inflammation is species specific. Complement was found to be necessary in rats and guinea pigs but not in C57BL/6J mice. In rats, within 4 h after initiation of an RPA reaction, serum alternative pathway hemolytic titers decreased significantly below basal levels, whereas classical pathway titers were unchanged. Thus the dermal reaction proceeds coincident with systemic activation of complement. The serine protease inhibitor BCX 1470, which blocks the esterolytic and hemolytic activities of the complement enzymes Cls and factor D in vitro, also blocked development of RPA-induced edema in the rat. These data support the proposal that complement-mediated processes are of major importance in the Arthus reaction in rats and guinea pigs, and suggest that BCX 1470 will be useful as an anti-inflammatory agent in diseases where complement activation is known to be detrimental.

Animals↗
PubMed2004

Mutational analyses of the recombinant globular regions of human C1q A, B, and C chains suggest an essential role for arginine and histidine residues in the C1q-IgG interaction.

The first step in the activation of the classical complement pathway by immune complexes involves the binding of the globular domain (gC1q) of C1q to the Fc regions of aggregated IgG or IgM. Each gC1q domain is a heterotrimer of the C-terminal halves of one A (ghA), one B (ghB), and one C (ghC) chain. Our recent studies have suggested a modular organization of gC1q, consistent with the view that ghA, ghB, and ghC are functionally autonomous modules and have distinct and differential ligand-binding properties. Although C1q binding sites on IgG have been previously identified, the complementary interacting sites on the gC1q domain have not been precisely defined. The availability of the recombinant constructs expressing ghA, ghB, and ghC has allowed us, for the first time, to engineer single-residue substitution mutations and identify residues on the gC1q domain, which are involved in the interaction between C1q and IgG. Because C1q is a charge pattern recognition molecule, we have sequentially targeted arginine and histidine residues in each chain. Consistent with previous chemical modification studies and the recent crystal structure of gC1q, our results support a central role for arginine and histidine residues, especially Arg(114) and Arg(129) of the ghB module, in the C1q-IgG interaction.

Alanine↗
PubMed2005

A direct role for C1 inhibitor in regulation of leukocyte adhesion.

Plasma C1 inhibitor (C1INH) is a natural inhibitor of complement and contact system proteases. Heterozygosity for C1INH deficiency results in hereditary angioedema, which is mediated by bradykinin. Treatment with plasma C1INH is effective not only in patients with hereditary angioedema, but also in a variety of other disease models, in which such therapy is accompanied by diminished neutrophil infiltration. The underlying mechanism has been explained primarily as a result of the inhibition of the complement and contact systems. We have shown that C1INH expresses the sialyl-Lewis(x) tetrasaccharide on its N-linked glycan, via which it binds to E- and P-selectins and interferes with leukocyte-endothelial adhesion in vitro. Here we show that both native C1INH and reactive center cleaved C1INH significantly inhibit selectin-mediated leukocyte adhesion in several in vitro and in vivo models, whereas N-deglycosylated C1INH loses such activities. The data support the hypothesis that C1INH plays a direct role in leukocyte-endothelial cell adhesion, that the activity is mediated by carbohydrate, and that it is independent of protease inhibitory activity. Direct involvement of C1INH in modulation of selectin-mediated cell adhesion may be an important mechanism in the physiologic suppression of inflammation, and may partially explain its utility in therapy of inflammatory diseases.

Animals↗
PubMed2004

[Hereditary angioedema of delayed onset].

Hereditary angioedema is a disorder characterized by episodes of angioedema of the skin, respiratory and gastrointestinal tract resulting from a defect in the C1 esterase inhibitor. The disease is hereditary. Inheritance is autosomal dominant with incomplete penetration. We report a 56-year-old man with edema in different locations as forearm, testicles and palms. It started recently. The study showed low levels of C4, and C1 inhibitor. He was diagnosed of hereditary angioedema and it was necessary the family study.

Age of Onset↗
PubMed1976

[Abdominal manifestations of hereditary angioneurotic edema. Importance of the exploration of the complement system (apropos of 29 families)].

Abdominal manifestations are almost constantly present (85% of cases) in the current form of hereditary Quincke's disease. In some cases, these abdominal manifestations occur even when cutaneomucosal edema is not present which leads to unwarranted often repeated and sometimes dangerous surgery. Apart from a story of heredity diagnosis of such troubles is possible, provided the total complement has been assayed to note its sharp fall. It can be subsequently explained by a functional defect of the C1 esterase inhibitor or alpha2-neuraminoglycoprotein.

Adolescent↗
PubMed1999

C1q and C4b bind simultaneously to CR1 and additively support erythrocyte adhesion.

Previously, we showed that soluble C1q bound specifically to CR1 on transfected cells. If the CR1-C1q interaction were to participate in immune complex clearance, then this interaction should support E adhesion. Using a tip plate adhesion assay, we found that immobilized C1q mediated adhesion of human E. E binding to C1q was specifically inhibited by polyclonal anti-CR1 Fab fragments. Intact C1 was not efficient as an adherence ligand until it was treated with EDTA or the C1 inhibitor to remove the C1r2C1s2 complex from C1, leaving C1q. Titration of C1q alone, C4b alone, and C1q + C4b indicated that the two complement ligands were additive in their ability to support CR1-mediated adhesion of E. Analysis of binding to immobilized CR1 using a BIAcore instrument documented that C1q, C4b, and C3b binding were independent events. Additionally, C1q-dependent binding of immune complexes and heat-aggregated IgG to E was documented. These experiments confirm that the immune adherence receptor in humans, CR1, is the single receptor for all of the opsonic ligands of complement, provide evidence for a single C1q binding site on LHR-D of CR1, and suggest that C1q may participate in immune clearance.

Antigen-Antibody Complex↗
PubMed2000

[Acquired angioneurotic edema. Clinical and biological characteristics in 9 patients].

OBJECTIVE: Angioneurotic edema (AE) is a rare but severe disease. Hereditary AE is the more well-known form. The acquired form is exceptional: the symptoms are the same but there are some biologic and treatment differences. We investigated the clinical and biochemical features in nine patients with acquired angioneurotic edema (AAE). PATIENTS AND METHODS: Four of the patients with type I AAE presented an accelerated metabolism of C1Inh, associated with a hematology disease. Their C4, C1q and C1Inh plasma levels were low. Four patients had type II AAE associated with an autoantibody to C1Inh. Their C1Inh plasma levels were normal or low but the functional levels were low in all four. One patient had AAE induced by oral contraceptives. The C1Inh plasma level was normal but the functional level was very low; there were no autoantibodies. Symptoms resolved when oral contraceptives were withdrawn and the C1Inh level returned to normal. DISCUSSION: Treatment of AAE is a difficult matter. For type I AAE, it consists in treating the associated disease. For type II AAE, the treatment goal is to lower the autoantibody level. Management of these diseases requires close collaboration between clinicians and biologists.

Adult↗
PubMed1976

Acquired angioedema with lymphoproliferative disorder: association of C1 inhibitor deficiency with cellular abnormality.

A patient with a lymphoproliferative disorder, angioedema, and an acquired deficiency of the inhibitor of the activated first component of complement was studied. The patient's complement profile revealed depletion of the first component of complement, which has not been seen in angioedema of the hereditary type. There was no evidence for C1-depleting activity in the patient's plasma. The majority of the patient's peripheral blood mononuclear cells resembled B cells in their memebrane receptor properties and in that they carried easily detectable immunoglobulin, predominantly IgM. However, these cells were unusual in that they phagocytosed both latex particles and C3-coated erythrocytes. Morphological study of the cells infiltrating the patient's lung revealed immature, atypical, and plasmacytoid lymphocytes and immunoblasts. Both the patient's peripheral blood mononuclear cells and a suspension of cells from the pulmonary infiltrate were capable of depleting the first component of complement and its inhibitor from homologous plasma. Normal ABO-compatible cells did not possess this property. The data suggested that the patient's abnormal lymphoid cells may have interacted with the complement system to produce a biochemical defect and a clinical syndrome closely resembling angioedema of the hereditary type.

Aged↗
PubMedDate not supplied

Hereditary angioedema: case report of a family.

Hereditary angioedema (HAE) is a rare disease resulting from deficiency of complement 1 esterase inhibitor (C1-INH). The clinical manifestations of this disease include recurrent attacks of self-limiting edema affecting face, extremities, gastrointestinal system and upper airways. In this report, we present eleven members of a family with HAE. Edema of the extremities was the most common symptom, occurring in ten patients. Three patients experienced severe laryngeal edema that required tracheotomy. Three patients developed facial and scrotal edema. Three patients experienced severe abdominal pain. The mean age at onset of symptoms was 11 years. C1-INH levels were undetectable in two patients and low in nine patients. CH50 was undetectable in all of the patients. C4 level for all patients was low. HAE in our first case, a 10-year-old boy, was diagnosed on the basis of low C1-INH, CH50 and C4, in addition to his familial history. Eleven members of this family, for whom laboratory studies could not be done, had similar symptoms and course. Two patients died as a result of laryngeal edema before establishment of diagnosis. This case report indicates the importance of recognition and early treatment of HAE to prevent a potentially fatal outcome.

Adult↗