"Relationships between serum BAFF and BBR expression [(BAFFR calcium signal modulating cyclophilic ligand interactor (TACI) and B cell maturation antigen (BCMA)] were determined on B cell subsets defined using immunoglobulin (Ig)D/CD38. Twenty pre-RTX and 18 rheumatoid arthritis patients relapsing after B cell depletion were included."xsd:string