CXCL13 and lymphoma: Consistently, the DDF subgroup had the highest serum concentrations of CXCL13 (which has been linked to lymphoma in patients with primary Sjögren's syndrome24), the highest levels of β2-microglobulin (a prognostic marker of poor outcomes in malignant lymphoma25), and altered expression of genes associated with B-cell signalling, germinal centres, lymphoproliferative disease, and oxidative stress.