Omalizumab for Chronic Idiopathic Urticaria: Potential to Taper Dose and Frequency?

Abstract

RATIONALE: Diagnosing autoreactivity in chronic spontaneous urticaria (CSU) can predict a more prolonged disease course, higher disease activity, need for higher doses of anti-histamines and the responsiveness to cyclosporin A and omalizumab. The BAT can identify these patients but is not widely available. Finding a combination of clinical data that helps identify these patients is clinically relevant. We aimed to analyse the clinical and laboratorial characteristics of BAT positive CSU patients and identify predictors of BAT positivity. METHODS: Cross-sectional study of 64 patients with CSU, with a 1-year follow-up. Data were analysed using SPSS: Student's t test, Chi-square test, Kappa coefficient, Odds Ratio, multivariable logistic regression model and ROC curve. RESULTS: Twenty-five patients were BAT negative and 39 were BAT positive. Six characteristics were significantly more frequent in the BAT positive group (p<0.05): a positive ASST, a UAS7> _16, presence of angioedema, presence of nocturnal symptoms, symptoms for >5 days/ week, and presence of anti-TG/TPO autoantibodies. This group also had a tendency for worse DLQI and UCT scores, a higher number of patients requiring therapy with omalizumab and had a lower total serum IgE. The combination of these characteristics showed good sensitivity and specificity at identifying BAT positive patients and statistical analysis demonstrated that they had a good discriminant power (area under the ROC curve 0.836). CONCLUSIONS: CSU patients can be divided into two distinct subsets using the BAT. BAT positive patients have a more severe disease and are strongly associated with 6 clinical characteristics that may be used in the future as surrogate markers. J ALLERGY CLIN IMMUNOL FEBRUARY 2019 AB50 Abstracts SATURDAY