Autoantibody-Specific Signalling in Pemphigus

Pemphigus is a severe autoimmune disease impairing barrier functions of epidermis and mucosa. Autoantibodies primarily target the desmosomal adhesion molecules desmoglein (Dsg) 1 and Dsg 3 and induce loss of desmosomal adhesion. Strikingly, autoantibody profiles in pemphigus correlate with clinical phenotypes. Mucosal-dominant pemphigus vulgaris (PV) is characterised by autoantibodies (PV-IgG) against Dsg3 whereas epidermal blistering in PV and pemphigus foliaceus (PF) is associated with autoantibodies against Dsg1. Therapy in pemphigus is evolving towards specific suppression of autoantibody formation and autoantibody depletion. Nevertheless, during the acute phase and relapses of the disease additional treatment options to stabilise desmosomes and thereby rescue keratinocyte adhesion would be beneficial. Therefore, the mechanisms by which autoantibodies interfere with adhesion of desmosomes need to be characterised in detail. Besides direct inhibition of Dsg adhesion, autoantibodies engage signalling pathways interfering with different steps of desmosome turn-over. With this respect, recent data indicate that autoantibodies induce separate signalling responses in keratinocytes via specific signalling complexes organised by Dsg1 and Dsg3 which transfer the signal of autoantibody binding into the cell. This hypothesis may also explain the different clinical pemphigus phenotypes.

[Anti-p200 pemphigoid: clinical, diagnostic and therapeutic aspects]

Anti-p200 pemphigoid is a rare autoimmune blistering dermatosis. The clinical course is heterogeneous. Typically, immunoglobulin G (IgG) antibodies are found on the floor of salt-split skin, which differentiates p200 pemphigoid from bullous pemphigoid. It is necessary to perform immunoblotting and enzyme-linked immunosorbent assays (ELISA) to confirm the diagnosis. Small amounts of dapsone are often sufficient for disease control. The clinical and diagnostic characteristics of anti-p200 pemphigoid and the principles of treatment are presented exemplified by two case reports.