As shown in Figure 5G, serum levels of BAFF in patients with IgG4-RD (2.60 ± 2.80 ng/mL) were significantly higher than those in HC (0.70 ± 0.42 ng/mL; P <0.001), while there were no significant differences in serum levels of BAFF between IgG4-RD and pSS patients (2.31 ± 2.65 ng/mL). Here, TNFSF13B is linked to immunoglobulin G4-related sclerosing disease.