UVB-induced acantholysis in endemic pemphigus foliaceus (fogo selvagem) and pemphigus vulgaris

Background: The autoantibody-mediated disease in fogo selvagem (FS) is aggravated by sunlight exposure. Objective: The aim of this study was to test whether UVB exposure of uninvolved skin of patients with FS (n = 21) enhances epidermal acantholysis and in vivo binding of FS autoantibodies as compared with a control group (n = 4). Another control group included 8 patients with pemphigus vulgaris (PV). Results: Exposure of uninvolved skin of FS to WE induces acantholysis (15/21 patients) with in vivo binding of IgG and C3 to the epidermal intercellular spaces (17/21 patients). Similar results were found in PV (6/8 patients). The test was negative in the control group. Conclusion: Sunlight exposure is harmful in the clinical course of patients with FS and those with PV. Protection from sunlight should be part of the treatment of these patients.