Fig. 3

APRIL and BAFF CSF levels in PCNSL during treatment. Patients with complete remission after methotrexate (MTX)-based polychemotherapy (n = 21) had significantly lower APRIL (a) and BAFF (b) CSF levels compared to patients with untreated newly diagnosed or relapsed PCNSL (n = 46). c–f Serial CSF analysis for APRIL (c, e) and BAFF (d, f) was performed before, during, and after methotrexate (MTX)-based polychemotherapy in 17 patients with newly diagnosed PCNSL (new DX). All of them experienced complete remission (CR) at the end of chemotherapy (CT). In 6 of these patients, relapse occurred during the observation period. c APRIL CSF levels decrease in 16/17 patients (94%) at CR, while in 1/17 patients (6%), APRIL levels remained stable (mean decrease: 63%). d BAFF CSF levels show variable courses during treatment and at CR (decrease in 10/17 patients (59%), increase in 6/17 (35%), stable in 1/17 (6%) with a mean decrease of 4%). e At relapse, APRIL CSF levels increase in 6/6 patients to a mean of 351% (range 123 to 633%. d BAFF CSF levels increase in 5/6 cases to a mean of 228% (range 85 to 311%)