The role of T cells, Tregulatory cells (Treg), follicular helper (TFH) cells, and CD4 cytotoxic T cells (CD4+CTL) in the pathogenesis of IgG4RD has been researched [11,12,13,14,15,31,32]. The gene discussed is CD4; the disease is immunoglobulin G4-related sclerosing disease.