Bullous Pemphigoid–Associated S aureus Increases Protease Activity from Keratinocytes and Promotes Unique BP180 Cleavage

Bullous pemphigoid (BP) is the most common autoimmune blistering disease that primarily affects the elderly (Kridin and Ludwig, 2018). Although BP etiology remains poorly understood, the key defining characteristic associated with pathogenesis is subepidermal blistering caused by loss of BP180 function (Sitaru et al, 2002). To better understand the impact of age on BP180 function, we analyzed protein lysates from undifferentiated primary human adult keratinocytes (KCs). Importantly, BP180 is present in 2 forms: a full-length protein that promotes adherence to the basement membrane at the dermal–epidermal junction and a cleaved form associated with the transition of KCs to the suprabasal layers of the epidermis (Franzke et al, 2009).