Pemphigus is an autoimmune blistering disease with two major subtypes, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Although most patients with PV show oral lesions, cutaneous type PV (C-PV) is a rare subtype clinically characterized by predominant cutaneous involvement with no or subtle mucosal lesions. Patients with PF present with only skin involvement; they do not have mucosal lesions. Serologically, autoantibodies against desmoglein (Dsg) 3 and Dsg1 are observed in C-PV whereas PF is associated with anti-Dsg1 antibodies only. Herein, we describe three cases of pemphigus presenting with predominant skin lesions and no mucosal involvement despite high anti-Dsg 3 autoantibody levels in chemiluminescent enzyme immune assays (CLEIAs). In addition, anti-Dsg 1 autoantibodies were positive in patients 2 and 3, but negative in patient 1 based on CLEIAs. Histological examination of the skin showed suprabasal acantholysis in patients 1 and 2, and blister formation in the upper epidermis in patient 3. Histopathology of the oral membrane in patients 1 and 2 showed subtle acantholysis in the suprabasal layer. Thus, we diagnosed patients 1 and 2 as having cutaneous type PV and patient 3 as having PF. Ethylenediaminetetraacetic acid-treated enzyme-linked immunosorbent assay demonstrated a low proportion of anti-Dsg3 autoantibodies recognizing Ca2+ -dependent epitopes, antibodies against which are thought to be the main contributor to acantholysis. Thus, along with Dsg1 antibodies, weak anti-Dsg3 antibodies could induce acantholysis in the skin, but they are insufficient to induce mucosal lesions.
Keywords: EDTA-treated ELISA; ELISA; cutaneous pemphigus vulgaris; desmoglein-3; pemphigus vulgaris.
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