Immunoglobulin G4-related disease associated with cutaneous vasculitis.

TLDR: Two patients with IgG4related disease associated with cutaneous vasculitis are examined, and the only subclass of human IgG that is unable to activate complement by the classical pathway is examined.

Abstract: © 2014 The Authors. doi: 10.2340/00015555-1707 Journal Compilation © 2014 Acta Dermato-Venereologica. ISSN 0001-5555 Immunoglobulin G (IgG) is composed of 4 Ig isotypes. A new entity called IgG4-related disease has recently been established (1). This disorder is characterised by an elevated serum level of IgG4 and an infiltration of IgG4+ plasma cells, as well as lymphocyte infiltration of various organs. IgG4 is the only subclass of human IgG that is unable to activate complement by the classical pathway. In the present report, we examine two patients with IgG4related disease associated with cutaneous vasculitis.