TSLP and immunoglobulin G4-related sclerosing disease: Briefly, we observed that TSLP significantly upregulated the expression of Ki-67 in IgG4-RD patients (29.8% ± 6.2% vs. 20.6% ± 3.8%, p = 0.031, Fig. 2A, B), while apoptosis was comparable between the two groups (Fig. 2C, D).