29 - Pemphigus

Abstract

Pemphigus is a group of IgG autoantibody-mediated blistering diseases of the skin and mucous membranes that includes three major forms: pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus. Histologically, there is intraepidermal blister formation due to the loss of cell–cell adhesion of keratinocytes. Immunopathologic studies serve to identify in vivo bound and circulating IgG autoantibodies against desmogleins found within desmosomes. Patients with pemphigus vulgaris and pemphigus foliaceus have IgG autoantibodies against desmoglein 3 and desmoglein 1, respectively, while patients with paraneoplastic pemphigus also have IgG autoantibodies against plakin molecules as well as a T cell-mediated autoimmune reaction that leads to an interface dermatitis. Systemic corticosteroids are a mainstay of therapy, but due to their toxicity at effective doses, immunosuppressive medications are regularly used as steroid-sparing agents. High-dose IVIg, which is non-immunosuppressive, and anti-CD20 monoclonal antibodies have been recently added to the therapeutic armamentarium for pemphigus. Anti-CD20 monoclonal antibodies (e.g. rituximab) are considered to be beneficial for patients who do not achieve clinical remission with systemic corticosteroids and/or immunosuppressive adjuvants as well as a first-line therapy option for moderate-to-severe pemphigus.