Changes in the autoimmune blistering response: a clinical and immunopathological shift from pemphigus foliaceus to bullous pemphigoid.

We describe a 64-year-old Brazilian man who developed bullous pemphigoid (BP) 12 years after pemphigus foliaceus (PF) was diagnosed. On his first presentation in 1992, histological examination revealed intraepidermal blistering and acantholysis at the granular layer, direct immunofluorescence (DIF) demonstrated intercellular deposits of C3 in the epidermis, and indirect immunofluorescence showed the presence of IgG antibodies against the intercellular spaces. In 2004, laboratory findings revealed a subepidermal blister with neutrophils and eosinophils (by histology), DIF demonstrated deposition of IgG and C3 along the basement membrane zone, salt-split skin showed IgG deposition in the epidermal side of the blister, and immunoblotting showed reactivity against BP180. The occurrence of two autoimmune blistering conditions in the same patient is a rare event, and may suggest an intermolecular epitope-spreading phenomenon.