Our analyses revealed that the IgG4-RD patients’ serum concentrations of TARC were positively correlated with the IgG4-RD RI score and the number of organs involved, but not correlated with the serum IgG4 level or the eosinophil number in peripheral blood (Fig. 2). This evidence concerns the gene CCL17 and immunoglobulin G4-related sclerosing disease.