A New Classification System for IgG4 Autoantibodies

IgG4 autoimmune diseases are characterized by the presence of antigen-specific autoantibodies of the IgG4 subclass, and contain well-characterised diseases such as MuSK myasthenia gravis, pemphigus and thrombotic thrombocytopenic purpura. In recent years several new diseases were identified, and by now fourteen antigens targeted by IgG4 autoantibodies have been described. The IgG4 subclass is considered immunologically inert and functionally...