Facts and Treatment of Bullous Pemphigoid: A Review

Abstract

Bullous pemphigoid (a type of pemphigoid) is an autoimmune pruritic skin disease that typically occurs in people aged over 60, that may involve the formation of blisters (bullae) in the space between the epidermal and dermal skin layers. It is classified as a type II hypersensitivity reaction, which involves formation of anti-hemidesmosome antibodies, causing a loss of keratinocytes to basement membrane adhesion. Pemphigus and bullous pemphigoid are autoantibody-mediated blistering skin diseases. In pemphigus, keratinocytes in epidermis and mucous membranes lose cell-cell adhesion, and in pemphigoid, the basal keratinocytes lose adhesion to the basement membrane. Pemphigus lesions are mediated directly by the autoantibodies, whereas the autoantibodies in pemphigoid fix complement and mediate inflammation. In both diseases, the autoantigens have been cloned and characterized; pemphigus antigens are desmogleins (cell adhesion molecules in desmosomes), and pemphigoid antigens are found in hemidesmosomes (which mediate adhesion to the basement membrane). This knowledge has enabled diagnostic testing for these diseases by enzyme-linked immunosorbent assays and dissection of various pathophysiological mechanisms, including direct inhibition of cell adhesion, antibody-induced internalization of antigen, and cell signaling. Understanding these mechanisms of disease has led to rational targeted therapeutic strategies.