CD4 and immunoglobulin G4-related sclerosing disease: Notably, the level of TSLPR was upregulated in CD4+ T cells (4.81% ± 0.60% vs. 2.97% ± 0.42%, p = 0.020) and CD19+ B cells (11.56% ± 1.64% vs. 6.12% ± 0.97%, p = 0.024, Fig. 1E) in IgG4-RD compared with HCs.