title: Autoantibodies in chronic idiopathic urticaria and nonurticarial systemic autoimmune disorders.
abstract: BACKGROUND
  Chronic idiopathic urticaria (CU) has been associated with other autoimmune diseases and basophil-activating autoantibodies to FcεRI or IgE. It is unknown whether patients with systemicautoimmune diseases have a similar prevalence of these autoantibodies.
  
  
  OBJECTIVE
  To compare the prevalences of basophil-activating autoantibodies (elevated CU Index) in patients with CU, rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Clinical characteristics and laboratory studies were examined for an association with the CU Index.
  
  
  METHODS
  Adult patients, 27 with CU, 27 with RA, and 26 with SLE, and 20 healthy controls were compared on the basis of the CU Index panel, anti-IgE, and antithyroid antibodies.
  
  
  RESULTS
  The CU Index values were significantly higher in the CU group when compared with the RA group but not when compared with the SLE group. 33% of CU, 23% of SLE, 3.7% of RA, and 15% of controls had apositive CU Index. Elevated antithyroid antibody levels did not correlate with a positive CU Index in any of the groups. An elevated CU Index in the SLE group was not associated with age, sex, ethnicity, disease severity, or history of atopy.
  
  
  CONCLUSIONS
  The CU Index values were elevated in patients with CU and SLE. The presence of these autoantibodies did not correlate with disease activity or presence of thyroid antibodies. Functional autoantibodies may not be specific for chronic idiopathic urticaria, and their role in nonurticarial systemic autoimmune diseases requires further investigation.
authors.affiliation: Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, The Ohio State University, Wexner Medical Center, Columbus, Ohio, USA.
authors.forename: Christine B
authors.initials: CB
authors.lastname: Cho
authors.forename: Shahan A
authors.initials: SA
authors.lastname: Stutes
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Altrich
authors.forename: Stacy P
authors.initials: SP
authors.lastname: Ardoin
authors.forename: Gary
authors.initials: G
authors.lastname: Phillips
authors.forename: Princess U
authors.initials: PU
authors.lastname: Ogbogu
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D001491:Basophils / Q000502:physiology; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D017455:Receptors, IgE / Q000276:immunology; D014581:Urticaria / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D017455:Receptors, IgE; D007073:Immunoglobulin E