IL7 and immunoglobulin G4-related sclerosing disease: In involved tissues of IgG4-related retroperitoneal fibrosis (IgG4-RPF), the co-localization of IL-6, BAFF, IL-7, IL-12 p70 and IL-23 with αSMA is observed by Zongfei J et al, and the expression levels of both IL-6 and IL-6R are higher than those in the control tissues, suggesting the pro-inflammatory properties of fibroblasts in affected tissues of IgG4-RD patients (53).