Evaluation of serum Claudin-3 levels in patients with chronic spontaneous urticaria

Background Chronic spontaneous urticaria (CSU) refers to urticaria with no identifiable cause persisting for more than 6 weeks. Few publications highlight the role of gut–skin axis and gut dysbiosis in CSU pathogenesis, pointing to the role of Claudin-3 (CLDN3) in maintaining gut barrier integrity. However, there were no studies evaluating the serum level of CLDN3 in CSU. Objective The aim is to assess the serum levels of CLDN3 in CSU patients versus healthy controls, and to correlate its level with some clinical parameters. Patients and methods This prospective case–control study was conducted involving 50 CSU patients and 30 matched healthy controls. Serum CLDN3 levels were measured using enzyme-linked immunosorbent assay. Urticaria severity was assessed using the Urticaria Activity Score 7. Results CSU patients (mean age 34.6±11.1 years, 68% female) exhibited significantly higher median serum CLDN3 levels compared with controls (5.6 vs. 3.5 ng/ml, P