In addition, the clonal expansion of CD4+ T cells with a cytotoxic function (CD4+ CTLs), which abundantly express SLAM family member 7 (SLAMF7), granzyme A (GZMA), IL-1β, and TGF-β, is observed in the affected organ of IgG4-RD (47, 48). Here, TGFB1 is linked to immunoglobulin G4-related sclerosing disease.