Expression of the human germinal-centre-associated lymphoma protein in diffuse large B-cell lymphomas in patients with rheumatoid arthritis.

Diffuse large B-cell lymphomas (DLBCL) can be subdivided into germinal centre (GC)-like and non-GC-like subtypes by CD10, BCL6 and MUM1/IRF4 status. We previously reported that patients with severe rheumatoid arthritis (RA) are at increased risk of non-GC DLBCL. This study examined a new GC-marker, human germinal-centre-associated lymphoma (HGAL) protein, in RA-DLBCL. Of 111, 38 (34%) DLBCL were HGAL-positive and showed less disseminated disease and a tendency toward improved overall survival compared to HGAL-negative cases. This supports that a majority of RA-DLBCL are of non-GC origin, indicating a specific role for activated peripheral B cells in the pathogenesis of RA-DLBCL.