In this study, we found that CD19+CD24−CD38hi plasmablasts/plasma cells are prominently increased in peripheral blood of untreated patients with IgG4-RD, correlating positively with serum IgG4, IgG4/IgG ratio, IgG4-RD RI, and the number of involved organs. This evidence concerns the gene CD19 and immunoglobulin G4-related sclerosing disease.