Search results for "Complement C1"
showing 10 items of 125 documents
Missense mutations in the coagulation factor XII (Hageman factor) gene in hereditary angioedema with normal C1 inhibitor.
2006
Hereditary angioedema is characterized by recurrent skin swelling, abdominal pain attacks, and potentially life-threatening upper airway obstruction. The two classic types are both caused by mutations within the complement C1 inhibitor gene. A recently described new type does not show a deficiency of C1 inhibitor and affects almost exclusively women. We screened twenty unrelated index patients with this new type of hereditary angioedema for mutations in the coagulation factor XII gene. Two different missense mutations were identified in exactly the same position within exon 9 of the F12 gene. 'Mutation 1' (1032C-->A), encountered in five patients, predicts a threonine-to-lysine substitution…
Hereditary Angioedema with Normal C1 Inhibitor
2013
Until recently it was assumed that hereditary angioedema was a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity, and protein in plasma were described. Since then, numerous patients and families with that condition have been reported. Most of the patients were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. In some families mutations in the coagulation factor XII (Hageman factor) gene were detected.
Development of systemic lupus erythematosus in a patient with selective complete C1q deficiency
1997
A 7-year-old male with recurrent erythematous and desquamated skin lesions and respiratory infections was diagnosed as selective complete C1q deficiency following detailed studies of the complement system. His asymptomatic sister also had selective complete C1q deficiency. During a follow up period of 3 years, his skin lesions persisted, he suffered from recurrent bronchopneumonias and glomerulonephritis developed. Renal function deteriorated with the appearance of anti-DNA antibodies. Renal biopsy was consistent with systemic lupus erythematosus. The patient was treated with immunosuppressive drugs, but died of renal failure. It is postulated that in this patient defective clearance of ant…
Reconstitution of the Complement Function in C1q-Deficient (C1qa−/−) Mice with Wild-Type Bone Marrow Cells
2001
Abstract Besides Ab-independent and Ab-dependent activation of the complement classical pathway in host defense, C1q plays a key role in the processing of immune complexes and in the clearance of apoptotic cells. In humans, C1q deficiency leads to systemic lupus erythematosus-like symptoms in over 90% of the cases, thus making this defect a strong disease susceptibility factor. Similarly, C1q-deficient mice (C1qa−/−) develop systemic lupus erythematosus-like symptoms, such as autoantibodies and glomerulonephritis. We have previously provided evidence that C1q is produced by cells of the monocyte-macrophage lineage. In this study, we have tested whether transplantation of bone marrow cells w…
C1-ESTERASE INHIBITOR REVERSES FUNCTIONAL CONSEQUENCES OF SUPERIOR MESENTERIC ARTERY ISCHEMIA/REPERFUSION BY LIMITING REPERFUSION INJURY AND RESTORIN…
2006
Activated complement contributes significantly to reperfusion injury after ischemia. This study explores functional consequences of C1-esterase inhibitor (C1-INH) treatment after superior mesenteric artery occlusion (SMAO)/ reperfusion using intravital microscopy. Thirty anesthetized, spontaneously breathing, male Sprague-Dawley rats underwent SMAO for 60 min followed by reperfusion (4 h). C1-esterase inhibitor (100 and 200 IU/kg body weight) or saline (0.9%) was given as a single bolus before reperfusion. Sham-operated animals (n = 10) without SMAO served as controls.Systemichemodynamicsweremonitoredcontinuously,arterial bloodgasesanalyzedintermittently, andleukocyte/ endothelial interacti…
The role of accessory cells in polyclonal T cell activation. I. Both induction of interleukin 2 production and of interleukin 2 responsiveness by con…
1983
Recent studies from other laboratories have shown that concanavalin A (Con A) acts at two separate steps in polyclonal T cell activation: interleukin 2 (IL2) production, and induction of responsiveness to IL2. Using a combination of techniques for the depletion of accessory cells from lymph node T cells, we have investigated which of these steps, if not both, is responsible for the known requirement for accessory cells in the Con A response. It was found that with increasing T cell purification, first the ability is lost to produce sufficient levels of endogenous IL2, whereas induction of IL2 responsiveness can still take place. Further removal of accessory cells however yields a population…
Distinct Roles of Classical and Lectin Pathways of Complement in Preeclamptic Placentae
2022
Pre-eclampsia is a pregnancy complication characterized by defective vascular remodeling in maternal decidua responsible for reduced blood flow leading to functional and structural alterations in the placenta. We have investigated the contribution of the complement system to decidual vascular changes and showed that trophoblasts surrounding unremodeled vessels prevalent in preeclamptic decidua fail to express C1q that are clearly detected in cells around remodeled vessels predominant in control placenta. The critical role of C1q is supported by the finding that decidual trophoblasts of femaleC1qa-/-pregnant mice mated toC1qa+/+male mice surrounding remodeled vessels express C1q of paternal …
Research on complement: old issues revisited and a novel sphere of influence
2003
Immunology in recent years has taken a somewhat surprising turn, expressed by a renewed interest in innate immunity. Especially intriguing is the regulatory role exerted by the innate components on the adaptive response, with Toll receptors and complement components being the most investigated. This function has been firmly established for complement protein CR2 (CD21) as part of the BCR co-receptor CD19/CD21/CD81. New findings are now providing a broader picture of complement and its tuning of the immune response; for example, complement proteins have been implicated in the control of T-cell-mediated responses. We will review some of these data here and summarize new discoveries in areas o…
Acquired C1 inhibitor (C1-INH) deficiency type II. Replacement therapy with C1-INH and analysis of patients' C1-INH and anti-C1-INH autoantibodies
1989
Abstract The response of two patients with autoantibody-mediated C1-inhibitor (C1-INH) deficiency to replacement therapy with C1-INH was studied over a period of 3 d. In patient 1 an acute attack of angioedema was successfully managed by infusion of 1,000 U of C1-INH concentrate. C1-INH function returned to normal levels within 30 min, while CH50 and C4 peaked after 6-7 h and C1 hemolytic activity reached 50-60% of normal after 3 d. Immediately after the injection an increase in C1-INH-anti-C1-INH complexes was observed. Based on NH2-terminal sequence analysis of the patients' Mr 96,000 C1-INH, it is concluded that this fragment is generated after cleavage of C1-INH in its active site by on…
Expression of C1q, a subcomponent of the rat complement system, is dramatically enhanced in brains of rats with either Borna disease or experimental …
1995
In situ hybridization, RT-PCR and Northern blot analysis as well immunohistochemistry were used to examine the expression of C1q, a subcomponent of the rat complement system, in brains of rats infected with Borna disease virus (BDV) and rats afflicted with experimental allergic encephalomyelitis (EAE) induced by the adoptive transfer of myelin basic protein specific T cells. C1q mRNA, which was not detected in normal brain, became clearly detectable using RT-PCR analysis by d14 post infection (p.i.) with BDV. Maximal levels of C1q mRNA were reached 21 days p.i. when inflammatory reactions in the brain were also at a peak. Similarly, C1q mRNA was elevated when the clinical symptoms of EAE be…