TNFSF4 and immunoglobulin G4-related sclerosing disease: We found the percentages of Tfh (9.50% ± 1.19% vs. 4.48% ± 0.41%, p < 0.001) as well as the expression levels of OX40L (21.8% ± 3.5% vs. 9.8% ± 1.0%, p = 0.002) and CD86 (21.3% ± 4.0% vs. 11.7% ± 1.9%, p = 0.044) were increased in IgG4-RD patients (Additional file 1: Fig. S6).