Recent data draw attention to the role of SDF-1/CXCL12 as a mediator involved in recruiting circulating fibrocytes to the inflamed tissue in chronic periaortitis, a fibrotic disorder in the spectrum of IgG4-RD (Nicastro et al., 2019). The gene discussed is CXCL12; the disease is immunoglobulin G4-related sclerosing disease.