Oral lesions of a patient with antidesmoglein 1 antibody-positive and antidesmoglein 3 antibody-negative pemphigus: Report of a case

The patient was a 47-year-old female who presented with skin and oral mucosal lesions. Edematous erythema and pigmentation with crusts were observed on the sinciput, precordium and upper back, and gingival erosion and redness were seen in the oral cavity. Clinically, pemphigus vulgaris (PV) was suspected. However, blood examination results were positive for antidesmoglein 1 antibody, but negative for anti-Dsg 3 antibody. Histopathological examination and direct immunofluorescence microscopic observation revealed superficial vesicular formation and IgG and C3 deposits in the epithelial cell membranes. A diagnosis of pemphigus foliaceus (PF) was made. Regarding the gingival lesions, histopathological cleavage of the suprabasal cell layer was detected, and direct immunofluorescence microscopy found intercellular IgG and C3 deposits in almost the entire epithelial cell layer. These findings were compatible with PV. As there was a contradiction between the clinical features and laboratory data, we further performed immunoblotting analysis. Autoantibodies against periplakin and C-terminal of the 180-kDa bullous pemphigoid antigen (BP 180) were detected. However, these autoantibodies were not considered to pathogenic. We report a rare case of anti-Dsg 1 antibody-positive and anti-Dsg 3 negative pemphigus with oral mucosal lesions.