Periostin in Bullous Pemphigoid: A Potential Biomarker of Disease Activity and Severity.

Elevated periostin levels are commonly observed in conditions characterised by increased IgE and eosinophilia, such as bullous pemphigoid (BP), which typically presents with eosinophil infiltration and elevated IgE levels. To explore the link between periostin levels and key clinical parameters in BP, serum periostin levels were assessed in 55 classic BP patients and 55 healthy controls using ELISA. Upon admission, the BP Disease Area Index (BPDAI) score, autoantibody levels, and peripheral blood immune cells of BP patients were evaluated. The investigation also employed the Olink proteomic platform to analyse circulating proinflammatory biomarkers. The results indicated significantly higher periostin levels in BP patients, showing a strong positive correlation with BPDAI scores, which was more pronounced compared to the correlation between BPDAI scores and BP 180 IgG or eosinophil counts. Correlation analysis revealed positive links between periostin levels in serum and attributes such as urticaria/erythema lesions, total IgE levels, serum BP180 IgG, BP180 IgE, BP230 IgE, and blood eosinophil counts. The findings from the Olink proteomic analysis provided additional evidence of the connection between periostin and type II inflammation in BP, which was further validated by the observed positive correlation between periostin and IL-13 using ELISA. Furthermore, it was observed that serum periostin levels decreased post-effective treatment. Overall, this study underscores a compelling association between periostin expression and the activity and severity of BP, as well as its reflection of type II inflammation.