Abstract: Objective To investigate the role of pemphigus IgG subclasses in the pathogenesis of pemphigus. Methods Pemphigus IgG subclasses from serum of a patient with active pemphigus vulgaris were purified by affinity chromatography. IgG subclasses were determined by indirect immunofluorescence and histopathology in the skin organ culture system. The reaction of IgG subclasses with membrane antigens on keratinocytes was observed by immunoblot analysis. Results The acantholysis was induced when the concentration of IgG subclasses reached to 0.5 mg/mL in pemphigus organ culture system. All four subclasses of IgG were reacted with 100 kD and 15 kD proteins on the surface of keratinocytes. Conclusions All four IgG subclasses are involved in the production of acantholysis in vitro. However, IgG subclasses with high titre may play an important part in the pathogenesis of pemphigus among patients in active stage.

Key words: Pemphigus, IgG