Fig. 1

APRIL and BAFF are significantly elevated in CNSL. Median CSF levels of APRIL (a) and BAFF (c) do not significantly differ in patients with newly diagnosed (PCNSL New Dx) or relapsed PCNSL (PCNSL Relapse) and newly diagnosed secondary CNSL (SCNSL New Dx), taken together as active CNSL. All patients with active CNSL had significantly elevated APRIL CSF levels compared to patients with other neurological diseases (ONDs) and compared to patients with other focal lesions (OFLs). b Subgroup analysis of patients with OFL (PBT, primary brain tumor; MBT, metastatic brain tumor; AID, autoimmune-inflammatory disease; NID, neuroinfectious disease) demonstrates significantly elevated CSF levels of APRIL in patients with active CNSL compared to all other subgroups. d CSF levels of BAFF were significantly elevated in active PCNSL when compared to PBT, MBT, and AID, but not to NID. Black lines indicate median, and dotted lines represent the diagnostic cut-off value of 6.59 ng/ml (b, APRIL) and 299 pg/ml (d, BAFF) as calculated. n.s., not significant (P > .05). *P < .05; **P < .01; ***P < .001