IGHG3 and primary biliary cholangitis: IgG3 antibodies have also been reported in other neurological antibody-associated diseases, including in MG (with ligand site-binding antibodies being selectively of the IgG3 subclass in some patients [22]), and predominant IgG3-seropositivity has been described in primary biliary cirrhosis (PBC) as well as in thrombocytopenic/haemolytic autoimmune conditions [31].