title: C1-bypass complement-activation pathway in patients with chronic urticaria and angio-oedema.
abstract: During the routine screening of 152 patients with urticaria or angio-oedema for hypocomplementaemia, 4 patients were found to have low serum levels of the third component of complement (C). These patients were noteworthy and differed from previous reports of patients with urticaria-like skin lesions and hypocomplementaemia because of the absence of immune-complex disease. In addition to the low C3, 2 of these patients were unique on the basis of low serum levels of haemolytic C1, C1q, C1s, and properdin factor B, but normal concentrations of C4 and C2. These C abnormalities may reflect a new clinical entity, and these cases form the first description in man of the C1-bypass complement-activation pathway.
mesh_terms: D000328:Adult; D000799:Angioedema / Q000097:blood / Q000276:immunology*; D002118:Calcium / Q000276:immunology; D002633:Chemotaxis; D003172:Complement C1 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis* / Q000378:metabolism; D005260:Female; D006461:Hemolysis; D006636:Histamine Release; D006801:Humans; D005779:Immunodiffusion; D007153:Immunologic Deficiency Syndromes / Q000097:blood; D008274:Magnesium / Q000276:immunology; D008297:Male; D009504:Neutrophils / Q000276:immunology; D009584:Nitrogen / Q000276:immunology; D011414:Properdin / Q000276:immunology; D011485:Protein Binding; D014581:Urticaria / Q000097:blood / Q000276:immunology*
chemical_list: D003172:Complement C1; D003181:Complement C4; D011414:Properdin; D003165:Complement System Proteins; D008274:Magnesium; D009584:Nitrogen; D002118:Calcium