Ectopic germinal centers have been described in salivary glands of IgG4-RD patients (Maehara et al., 2012), and the role of SDF-1/CXCL12 in the formation of these ectopic lymphoid structures are well established (Corsiero et al., 2012). This evidence concerns the gene CXCL12 and immunoglobulin G4-related sclerosing disease.