Bullous pemphigoid (BP) is the most common autoimmune blistering disease, characterized by autoantibodies targeting the dermal-epidermal junction, such as BP180 and BP230, leading to skin inflammation and tissue damage. While markers of autoimmunity and inflammation are elevated in the blister fluid and/or sera of BP patients, the identification of novel biomarkers remains essential for early diagnosis and therapeutic advances. This project investigates pentraxin 3 (PTX3), an inflammatory mediator with a key role in immune regulation, as a potential biomarker in BP. Preliminary studies have identified elevated levels of PTX3 in BP patient sera, prompting further investigation into its local expression, functional impact on keratinocytes, and role in immune complex-induced inflammation. Using in vitro and ex vivo approaches, this study explores the significance of PTX3 in BP pathogenesis, particularly its involvement in neutrophil-driven tissue damage. Ultimately, this project aims to establish PTX3 as an early biomarker (or drug target) for BP, with potential implications for disease monitoring and targeted therapeutic strategies. The findings will contribute to a deeper understanding of autoimmune blistering diseases and foster novel approaches to patient care within the framework of the Research Training Group.