Clinicopathologic features of I g G / I g A pemphigus in comparison with classic ( I g G ) and I g A pemphigus

Background The pemphigus group is characterized by the presence of circulating immunoglobulins against desmosomes. IgG/IgA pemphigus is defined by the presence of IgG and IgA cell surface deposits upon direct immunofluorescence ( DIF ) and/or circulating IgG and IgA autoantibodies upon indirect immunofluorescence. Previous reports of patients with IgG/IgA pemphigus are sparse. Whether IgG/IgA pemphigus is best classified as a subtype of IgG (classic) pemphigus or IgA pemphigus, or as a distinct entity, has yet to be determined. Objectives We compared the features of patients with IgG/IgA pemphigus to those of IgG pemphigus and IgA pemphigus. Methods Retrospective clinicopathologic study of patients with IgG, IgG/IgA, and IgA pemphigus evaluated at our clinic (1993–2013). Results We included 26, 13, and seven patients with IgG, IgG/IgA, and IgA pemphigus, respectively. Patients with IgG/IgA pemphigus did not differ significantly from patients with IgG pemphigus in terms of clinical and microscopic features, DIF findings, anti‐desmoglein antibody values, and treatments required. However, patients with IgG/IgA pemphigus were significantly different from patients with IgA pemphigus regarding intertriginous distribution ( P = 0.038) and pustular lesions ( P < 0.001), acantholysis ( P = 0.043), and presence of intercellular C3 deposits on DIF ( P < 0.001). Conclusion Comparative clinicopathologic data imply that IgG/IgA pemphigus may best be regarded as a variant of IgG pemphigus and distinct from IgA pemphigus.