The frequencies of CD19 + CD24-CD38hi B cells were positively correlated with IgG4 levels and the IgG4/IgG ratio in IgG4-RD patients (r = 0.4875, P = 0.0063; r = 0.3987, P = 0.0321; respectively; Figure 6G-H), indicating that CD19 + CD24-CD38hi B cells might play an important role in IgG4-RD. The gene discussed is CD19; the disease is immunoglobulin G4-related sclerosing disease.