CD27 and immunoglobulin G4-related sclerosing disease: Another study by this team identified an expansion of CD19+CD27+CD20−CD38hi plasmablasts, which could be depleted by anti-CD20 treatment, in IgG4-RD patients, and the re-emergence of the de novo distinct oligoclonal plasmablasts was correlated with relapse of IgG4-RD34.