The role of autoimmune testing in chronic idiopathic urticaria

The clinical implications of autoimmune testing in chronic idiopathic urticaria (CIU) are not well established.

To identify the association of autoimmune biomarkers in CIU with disease severity.

We retrospectively evaluated 195 patients with a diagnosis of CIU for the presence of antinuclear antibody (ANA), anti-thyroglobulin antibody (ATG), anti-thyroperoxidase antibody (ATPO), and Chronic Urticaria (CU) Index. The patients were categorized into controlled and refractory subgroups based on their response to antihistamines with or without a leukotriene receptor antagonist.

The percentage of patients with a positive test for ANA (titer>1:160), ATG, ATPO, and CU Index were 29%, 6%, 26%, and 38%, respectively. Among those tested, the percentage of patients categorized as refractory was significantly higher in those with a positive CU index (80% vs 46%; P = .01) or a positive ANA titer (50% vs 30%; P = .04) than those with negative test results; however, a similar relationship was not observed for ATPO or ATG antibodies. Odds ratios of individual or combinations of autoimmune biomarkers in CIU were examined for associations with refractoriness to antihistamines with or without a leukotriene receptor antagonist. The CU Index alone has an odds ratio of 4.5 (P = .005), whereas the combination of ANA, ATG, and ATPO has an odds ratio of 3.1 (P = .01) and ANA alone has an odds ratio of 2.3 (P = .04) for correlating with a refractory outcome.

Our data indicate the CU Index independently has the strongest correlation with disease severity followed by the combination of ANA, ATG, and ATPO and the ANA alone.