TNFRSF13B and immunoglobulin G4-related sclerosing disease: Interestingly, the expression levels of TACI and BAFFR were lower in IgG4-RD than in HCs, and BCMA was highly expressed in B cells, especially plasmablasts and dividing plasmablasts from IgG4-RD compared with HCs (Supplemental Figure 2G).