The MFI of BAFF-R in Breg cells of IgG4-RD patients was lower than that of HC (208.5 ± 218.4, 344.1 ± 158.4, respectively; P <0.05) and pSS patients (340.4 ± 114.5; P <0.05). This evidence concerns the gene TNFRSF13C and immunoglobulin G4-related sclerosing disease.