This effect is not exclusive for IgG4-mediated diseases where antibodies are the major effectors of pathology like in IgG4 autoimmune diseases (IgG4-AID); IgG4-related disease (IgG4-RD) also responds well to anti-CD20-mediated BCDT (13). The gene discussed is MS4A1; the disease is immunoglobulin G4-related sclerosing disease.