D3.08 - Biomarker Profiles and Autoimmune Features in Patients with Chronic Urticaria: A Clinical–Laboratory Analysis

Chronic urticaria (CU) is a heterogeneous inflammatory disease with multifactorial pathogenesis. Biomarkers such as total immunoglobulin E (IgE), eosinophil counts, thyroid autoantibodies, and the autologous serum skin test (ASST) have been proposed as useful tools for defining disease endotypes, assessing prognosis, and guiding therapeutic decisions. Elevated IgE levels and eosinophilia are commonly associated with type 2–driven immune activation, whereas thyroid autoimmunity and ASST positivity suggest autoimmune mechanisms. Clarifying the distribution and interplay of these biomarkers in real-life populations is essential for advancing biomarker-driven stratification. This study aimed to evaluate biomarker profiles and autoimmune features in a Southeastern European cohort of patients with CU.

A retrospective clinical–laboratory study was conducted in a single-center cohort of 55 patients with CU hospitalized between July 2024 and August 2025. Data were extracted from discharge summaries and included demographics, total IgE levels, absolute and relative eosinophil counts, thyroid autoantibodies (anti-thyroid peroxidase and anti-thyroglobulin), thyroid function parameters, and ASST results. Biomarker distributions and co-occurrence patterns were analyzed using descriptive statistical methods, with stratification according to atopic and autoimmune profiles. Written informed consent for publication of anonymized clinical data was obtained from all patients.

The cohort comprised 55 patients (46 women, 9 men; mean age 42.6 ± 13.8 years). Elevated IgE levels (>100 IU/mL) were observed in 44.4% of patients, with a mean value of 386 IU/mL (range 124–1120), compared with 42 IU/mL (range 8–98) in patients with normal IgE levels. Absolute eosinophilia (>500/µL) was present in 16.4% of patients, while mild eosinophilia (300–500/µL) was observed in 20.0%. Thyroid antibody positivity was detected in 29.1% of patients, with subclinical hypothyroidism documented in 10.9%. A positive ASST was found in 61.8% of patients, indicating a high prevalence of autoimmune endotypes among hospitalized CU patients.

Distinct co-occurrence patterns were identified, including elevated IgE combined with thyroid antibody positivity in 10.9% of patients, and low IgE levels (<40 IU/mL) with ASST positivity in 14.5%. These findings highlight the immunological heterogeneity of CU and challenge a strict dichotomy between type 2–driven and autoimmune disease endotypes.

This real-world analysis demonstrates that chronic urticaria is characterized by heterogeneous biomarker constellations defining distinct immunological endotypes. The high prevalence of ASST positivity and thyroid autoimmunity underscores the relevance of autoimmune pathways, while elevated IgE levels and eosinophilia reflect type 2–driven immune mechanisms. Integrating biomarker assessment into routine clinical practice may refine patient stratification, inform prognosis, and support individualized therapeutic decision-making.