Diffuse large B cell lymphoma in rheumatoid arthritis patients is associated with elevated B-cell driving factors including CXCL13

Patients with rheumatoid arthritis (RA) are at increased risk of diffuse large B cell lymphoma (DLBCL) compared to the general population. Here, we explored the inflammatory profiles in the blood of RA patients who had developed DLBCL. RA-DLBCL patients had significantly higher levels of the pro-inflammatory markers TNF, IL-8, CXCL9, APRIL, and particularly CXCL13 (median 796 vs. 206 pg/mL, p = 0.001), compared to RA controls. By including an extensive autoantibody panel of rheumatoid factor, IgG anti-CCP2, anti-citrullinated protein antibodies (ACPA) fine-specificities, and other anti-modified protein antibodies, all RA-DLBCL patients were autoantibody seropositive. Yet, RA-DLBCL patients did not display significantly different autoantibody signatures compared to RA controls. The levels of immunoglobulin free light chains and C-reactive protein were similar in RA-DLBCL patients and RA controls. In conclusion, RA-DLBCL patients exhibit pro-inflammatory signatures with elevated markers that are important for B cells and may contribute to enhanced B-cell activation and promote lymphoma development.