title: [Formation of IgG antibodies to C1 inhibitor as the cause of life-threatening angioedema].
abstract: A clinical picture with recurrent (in some cases potentially fatal) edema of skin and internal organs based not on a hereditary C1 inhibitor deficiency, but an acquired loss of C1 inhibitor activity due to antibodies is described for the first time in two patients. The clinical symptoms commenced in middle age patients between 40 and 46 years old. Anti C1 antibodies of the IgG were found in both patients. Quantitatively, these C1 inhibitor protein was in the lower range of normal, whereas no inhibitor activity could be demonstrated functionally. The function of the complement components C1, C2 and C4 was greatly reduced. The therapeutic use of C1 inhibitor concentrate at a high doses (6 X 500 U) as well as administration of high-dose corticosteroids in several emergency situations was unsuccessful.
mesh_terms: D000328:Adult; D015119:Aminocaproic Acid / Q000627:therapeutic use; D000799:Angioedema / Q000209:etiology* / Q000276:immunology / Q000628:therapy; D003172:Complement C1 / Q000032:analysis; D003174:Complement C1 Inactivator Proteins / Q000008:administration & dosage / Q000032:analysis / Q000276:immunology*; D003175:Complement C2 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D003613:Danazol / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use
chemical_list: D003172:Complement C1; D003174:Complement C1 Inactivator Proteins; D003175:Complement C2; D003181:Complement C4; D007074:Immunoglobulin G; D003613:Danazol; D015119:Aminocaproic Acid; D011241:Prednisone
vernacular_title: IgG-Antikörperbildung gegen C1-Inhibitor als Ursache lebensbedrohlicher Angioödeme.