The current study in 135 patients confirms recent findings11 that the presence of dominant IgG4+ BCR clones in peripheral blood determined by NGS clearly distinguishes patients with IgG4‐RD of the biliary tree and pancreas from disease controls with similar clinical presentation, such as pancreatobiliary cancer or PSC. The gene discussed is BCR; the disease is immunoglobulin G4-related sclerosing disease.