Expression of BAFF-R and TACI in reactive lymphoid tissues and B-cell lymphomas

Aims:  The receptor for B-cell-activating factor belonging to the tumour necrosis factor family (BAFF-R) and transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) have been established as binding molecules to BAFF. The aim of this study was to determine the pathological diagnostic roles and clinical significance of these BAFF-binding receptors in B-cell neoplasms. Methods and results:  Expression of BAFF-R and TACI was examined immunohistochemically in reactive lymphoid tissues and B-cell lymphomas including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), marginal zone B-cell lymphoma (MZBCL) and plasma cell myeloma (PCM). In reactive tissues BAFF-R was expressed exclusively in the cells of the mantle zone and within the germinal centres (GCs), whereas TACI appeared positive in the scattered cells in extrafollicular areas. There were variable patterns of expression of BAFF-R and TACI amongst the different types of B-cell lymphomas (MCL and FL: BAFF-R+TACI−; PCM: BAFF-R−TACI+; DLBCL and MZBCL: variable expression). Reverse transcriptase-polymerase chain reaction studies supported these results. The overall survival of the BAFF-R+ DLBCL group was significantly better than that of the BAFF-R− group. Conclusions:  These results indicate that the assessment of expression of BAFF-binding receptors aids subclassification and prognostication of DLBCL.