Evaluating the tissue expression of thyroid peroxidase in chronic spontaneous urticaria patients.

Chronic spontaneous urticaria (CSU) characterized by recurrent wheals and/or angioedema, remains a challenging condition. Autoallergic and autoimmune mechanisms (Type I and IIb) have been recognized for CSU pathogenesis. Studies have demonstrated the association between CSU and serum anti-thyroid peroxidase (TPO) antibodies (Abs). However, the potential for increased TPO expression within affected skin tissue of CSU patients is unclear. Patients diagnosed with CSU were recruited from the UCARE center of Mashhad University of Medical Sciences, the case group. Matched healthy individuals who underwent cosmetic surgery served as the control group. Skin biopsies were obtained from active wheal lesions in the CSU patients. Thyroid function tests (TFTs) and serum anti-TPO Ab levels were measured in both groups. Immunohistochemistry (IHC) staining was used to assess skin biopsy samples. A total of 60 participants were enrolled, including 30 CSU patients and 30 healthy controls. Hypothyroidism was significantly more prevalent in the case group compared to controls (p = 0.007). Additionally, the patients exhibited a significantly higher rate of positive serum anti-TPO Ab compared to the healthy individuals (p = 0.001). Notably, IHC staining revealed no TPO expression in the skin samples of either group. This study demonstrated that elevated serum anti-TPO Ab levels in CSU patients may not directly translate to TPO expression within affected skin tissue. While further research with larger cohorts is warranted, our findings contribute to the understanding of the histopathological underpinnings of CSU in relation to TPO, anti-TPO Ab, and potential autoimmune mechanisms.