In other autoimmune diseases such as SLE (20, 21), IgG4-related disease (22), and anti-PLA2R1 related membranous nephropathy (23) the plasmablast frequency has been reported to be related to disease activity, as were absolute plasmablast numbers in SLE (20) and IgG4-related disease (22). Here, PLA2R1 is linked to immunoglobulin G4-related sclerosing disease.