Clinical, Histopathologic, and Immunohistochemical Features of Patients with IgG/IgA Pemphigus.

Pemphigus is an autoantibody-mediated blistering disease. In addition to conventional pemphigus vulgaris and pemphigus foliaceus, several other types have been reported. Among them, IgG/IgA pemphigus is less well defined and seldom reported. To characterize the clinical, histopathologic, and immunohistochemical presentation of IgG/IgA pemphigus, we retrospectively identified 22 patients with the disease at a referral center in Taiwan. These patients showed two types of skin lesion: annular or arciform erythemas with blisters or erosions (45.5%) and discrete erosions or blisters such as those in conventional pemphigus (54.5%). Mucosal involvement was found in 40.9%. Histopathologic analysis identified acantholysis (77.3%) and intra-epidermal aggregates of neutrophils (40.9%) and eosinophils (31.8%). Direct immunofluorescence studies showed IgG/IgA (100%) and C3 (81.8%) depositions in the intercellular space of the epidermis. In immunohistochemical staining, patients with IgG/IgA pemphigus demonstrated significantly higher levels of epidermal expression of interleukin-8 and matrix metalloproteinase-9 than those with conventional pemphigus (p < 0.05). In conclusion, although IgG/IgA pemphigus is heterogeneous in presentation, it shows characteristic features that are different from other forms of pemphigus and should be considered a distinct type of pemphigus.