Background: Understanding the etiopathogenesis of chronic spontaneous urticaria (CSU) remains a challenge.
The clinical and laboratory characteristics relating to its histocompatibility profile and autoimmunity are constant research
Objectives: To analyze the clinical and laboratory characteristics of patients with CSU by means of a cross-sectional
study, focusing on the histocompatibility profile, presence of antinuclear antibodies (ANA) and presence of
antithyroperoxidase antibodies (anti-TPO).
Materials & Methods: Sixty-seven adults with CSU were analyzed. The autologous serum skin test (ASST), ANA and
anti-TPO were performed in all cases and MHC classes I and II (loci A, B and DR) were evaluated in 49 patients.
Results: The factors that worsened urticaria included use of non-steroid anti-inflammatory drugs, emotional stress and
physical stimuli, reported by 27%, 16% and 15% of these patients, respectively. The ASST test was positive in 49 patients
(73%) and anti-TPO and ANA were present in 15 (22.4%) and 7 (10.5%), respectively. The OR (with 95% CI) for the
association between ANA and anti-TPO was 5.94 (1.16-30.42), and thus statistically significant. There was a favorable
association (with statistical significance) between HLA B*50 and patients with CSU, with OR (95% CI) of 2.96 (1.17-
Conclusion: A significant favorable association was found between these patients and HLA B*50, and between the
presence of anti-TPO and ANA. The greater prevalence of HLA B*50 in these patients and the association between ANA
and anti-TPO reinforce the possibility that an immunogenic mechanism may be the triggering factor for CSU.