TGFB1 and immunoglobulin G4-related sclerosing disease: Serum levels of TGF-β in patients with IgG4-RD (16.94 ± 7.73 ng/mL) were comparable to those in HC (17.73 ± 4.81 ng/mL; P = 0.643), and both were significantly higher than in patients with pSS (14.16 ± 5.66 ng/mL; Figure 5I).