Therefore, it is interesting to investigate the correlations between Tfh-related serum cytokine levels and IgE, as well as to compare the IgE level immunohistologically, between groups A and B, which may shed light on the role of IgE in the pathogenesis of IgG4-RD in future studies. The gene discussed is IGHE; the disease is immunoglobulin G4-related sclerosing disease.