title: Acquired angioedema with C1 inhibitor deficiency: is the distinction between type I and type II still relevant?
abstract: BACKGROUND
  Acquired angioedemas are divided into type I associated with lymphoproliferation and type II caused by anti-C1-inhibitor antibodies. Recent reports have suggested that this distinction is not so clear-cut, mainly because of the presence of antibodies against the C1 inhibitor in some cases belonging to the type I group. We report herein 2 additional cases of acquired angioedema with anti-C1-inhibitor antibody.
  
  
  METHODS
  One man and 1 woman had had acquired angioedema for several years. In the man, a monoclonal component had been detected several years before the present study. In the second patient, a monoclonal component was detected during the study. The following data were studied on successive blood samples collected during angioedema manifestations: complement component levels, functional activity of the classical pathway, functional and antigenic C1 inhibitor doses, ELISA test to detect autoantibodies to C1 inhibitor and Western blot analysis of the C1 inhibitor.
  
  
  RESULTS
  In both patients, CH50 and C4 activities were decreased, and an autoantibody to C1 inhibitor was detected. In 1 case, the antibody appeared after the monoclonal component; in the second case, it appeared before and belonged to a different immunoglobulin class.
  
  
  CONCLUSIONS
  Our data suggest that the distinction between type I and type II acquired angioedema is no longer valid because of overlapping in some cases.
authors.affiliation: Department of Dermatology, CHRU Hôtel-Dieu, Clermont-Ferrand, France. mc.dincan@wanadoo.fr
authors.forename: M
authors.initials: M
authors.lastname: D'Incan
authors.forename: A
authors.initials: A
authors.lastname: Tridon
authors.forename: D
authors.initials: D
authors.lastname: Ponard
authors.forename: C
authors.initials: C
authors.lastname: Dumestre-Pérard
authors.forename: M
authors.initials: M
authors.lastname: Ferrier-Le Bouedec
authors.forename: G
authors.initials: G
authors.lastname: Bétail
authors.forename: P
authors.initials: P
authors.lastname: Souteyrand
authors.forename: D
authors.initials: D
authors.lastname: Caillaud
mesh_terms: D000368:Aged; D000799:Angioedema / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology; D015153:Blotting, Western; D003174:Complement C1 Inactivator Proteins / Q000172:deficiency* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005148:Facial Dermatoses / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D012867:Skin / Q000276:immunology / Q000378:metabolism / Q000473:pathology
chemical_list: D001323:Autoantibodies; D003174:Complement C1 Inactivator Proteins