Auto-antibodies in Chronic Idiopathic Urticaria (CIU) and Non-urticarial Systemic Autoimmune Disorders

Abstract

T U E S D A Y 841 Auto-antibodies in Chronic Idiopathic Urticaria (CIU) and Non-urticarial Systemic Autoimmune Disorders S. A. Stutes, C. B. Cho, M. Altrich, S. P. Ardoin, P. U. Ogbogu; The Ohio State University Medical Center, Columbus, OH, Viracor-IBT Laboratories, Lee’s Summit, MO. RATIONALE: 30-50% of patients with CIU have ‘‘functional’’ autoantibodies to FceRI or IgE asmeasured by basophil histamine release assay or basophil activation markers. It is unknown if patients with systemic autoimmune diseases have a similar prevalence of these auto-antibodies. METHODS: Adult patients, 26 with CIU, 27 with Rheumatoid Arthritis (RA), and 26 with Systemic Lupus Erythematosus (SLE), were recruited from an allergy clinic and a rheumatology clinic. 20 healthy controls were compared. The patients with RA and SLE did not have chronic urticaria. Atopy history and disease activity were obtained. The CU Index Panel (basophil histamine release assay), anti-IgE, and anti-thyroid antibodies were performed by Viracor-IBT laboratories. RESULTS: CU Index values were significantly higher in the CIU group (mean 15.6) as compared to the RA group (mean 2.31, p50.007), but not in the SLE group (mean 7.6, p50.079). In contrast to patients in the RA and control groups, 11% of SLE and 7.6% of CIU patients had elevated antiIgE antibody levels (>188 ng/mL). Elevated anti-thyroid peroxidase (TPO) levels did not correlate with a positive CU Index. Elevated CU Index and anti-IgE values in the RA and SLE groups were not associated with disease severity. CONCLUSIONS: The CU Index values differentiated CIU patients from RA patients, but not from SLE patients. Interestingly, SLE patients were found to have ‘‘functional’’ auto-antibodies without associated urticaria. The presence of auto-antibodies did not correlate with disease activity or having thyroid antibodies. Functional auto-antibodies may not be useful in distinguishing autoimmune chronic urticaria from non-urticarial autoimmune disorders.