005 Ectopic Lymphoid Structures Harbor Desmoglein-Specific B Cells in the Chronic Skin Lesions of Patients with Pemphigus

Abstract

Pemphigus is a chronic autoimmune bullous diseases characterized by the production of autoantibodies against desmogleins (desmoglein 1 and 3). Antibody-producing B cells are usually developed and activated in the germinal centers of secondary lymphoid organs such as lymph nodes and spleen. Ectopic lymphoid structures (ELSs) resembling the germinal centers have been recognized at inflamed tissues of various infectious or autoimmune diseases; however, the ELSs have been undetermined in the skin lesions of autoimmune bullous diseases including pemphigus. We firstly identified the skin ELSs in the chronic lesions of patients with pemphigus. We found tight clusters of B and CD4+ T cells in the dermis of chronic blisters lasting at least 4 months from the patients with pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus. The clusters in the dermis contain peripheral node addressin+ venules which are only observed in secondary lymphoid organs. Furthermore, lymphotoxin β, podoplanin+ venules, follicular dendritic cells, and CD11c+ dendritic cells were also detected in the ELSs. Desmoglein-specific B and plasma cells are present in the peripheral areas of ELSs. CD4+ T cells in the skin ELSs consist of many CXCL13+ cells and a few CXCR5+PD-1+CD4+ T cells, which show the features of T follicular helper cells. The chronic blisters containing ELSs disappeared after the treatment of intralesional corticosteroid.