In the same way, since relapses are frequent after B-cell reconstitution and appear to be rare without CD19 B-cell detection, individually tailored RTX-infusion schedules based on CD19 B-cell reappearance, as recently reported during AAV [39], should be further studied in IgG4-RD. Here, CD19 is linked to immunoglobulin G4-related sclerosing disease.