Ultrastructural localization of autoantigens of intercellular IgA vesiculopustular dermatosis in cultured human squamous cell carcinoma cells

Abstract

A new disease characterized by the presence of in vivo bound and/or circulating IgA anti-intercellular antibodies has recently been identified [3, 6, 8-10, 12, 14, 16-18, 20-22]. We propose the term 'intercellular IgA vesiculopustular dermatosis ' (IAVPD) for this entity, a designation similar to ' linear IgA bullous dermatosis ' [4]. I A V P D seems to be divided into at least two distinct subtypes: intraepidermal neutrophilic IgA dermatosis ( IEN type) and subcorneal pustular dermatosis-like cases (SPD type) [13]. We previously examined the antigen substances for the IgA anti-intercellular antibodies in patients ' sera, and suggested that IAVPD is different f rom pemphigus and is heterogeneous in terms of the antigens to which IgA autoantibodies bind [5]. In vivo ultrastructural localization of immune deposits in patients ' skin was observed with immunoelectron microscopy using immunoperoxidase methods [11, 16]. However, the precise localization of I A V P D antigen in the epidermal cell surface is still unknown. In the present study, in order to demonstrate the ultrastructural localization of I A V P D antigen(s), we employed non-fixed cultured cells and immunoelectron microscopy using immunogold methods. Fur thermore, to stabilize the cell membrane , immunolabell ing was performed in a medium containing N a N 3. Al though the possibility cannot be excluded that there is a difference in the localization of the IAVPD antigen(s) between cultured cells and normal human epidermis, we were successful in demonstrat ing the expression sites of I A V P D antigen(s).