Cerebrospinal Fluid IL-6 Plus IL-10 As Effective Diagnostic Biomarkers for Secondary Central Nervous System Lymphoma

Background : Secondary central nervous system lymphoma (SCNSL) characterized by the involvement of the CNS at initial diagnosis of systemic lymphoma or in the setting of relapse. Accurate diagnosis and therapeutic response of SCNSL are particular challenges, which need to be improved. We aimed to evaluate the diagnostic and the post-therapeutic prognostic value of cerebrospinal fluid (CSF) cytokine in patients with SCNSL.

Methods: In this retrospective study involving 234 NHL patients and 53 other CNS patients, the NHL patients was divided into two sub-groups based on with and without CNS involvement: SCNSL (n=57) and non-SCNSL (n=177). The CSF cytokine profiles (interleukin (IL)-2, -4, -6, and -10, tumor necrosis factor-α, interferon-γ, and IL-17A) of these patients were measured by cytometric bead assay and evaluated the ability of CSF cytokine levels as diagnostic, therapeutic and prognostic biomarkers for SCNSL.

Results: CSF IL-6 and IL-10 levels were significantly higher in SCNSL patients than non-SCNSL and other CNS patients. CSF levels of IL-6 and IL-10 were significantly higher in patients with an stage at Ⅲ and Ⅳ, CSF WBC counts>5/µL, CSF protein ≥0.45g/L.Using a CSF IL-6 cut-off value of 10.13 pg/ml yielded a diagnostic sensitivity and specificity was 62.34% and 87.57%, respectively (AUC, 0.7798; 95% CI, 0.7083 to 0.8514); For a CSF IL-10 cutoff value of 7.82, the sensitivity was 76.23%, and the specificity was 98.31% (AUC, 0.8164; 95% CI, 0.7466 to 0.8862). Combined CSF IL-6 and IL-10 significantly improved the diagnostic effect of SCNSL (AUC, 0.8959; 95% CI, 0.8371 to 0.9547). The levels of IL-6 and IL-10 in cerebrospinal fluid of SCNSL patients who responded to intrathecal chemotherapy were significantly decreased during follow-up, while the levels of these two cytokines showed fluctuating changes in patients with progressive SCNSL. Moreover, poor Progression free survival (PFS) for patients with SCNSL was associated with the increased CSF IL-10 level at diagnosis with CNS involvement (P=0.035), but not with the increased CSF IL-6 level.

Conclusion: Our study confirmed CSF level of IL-6 and IL-10 were potentially effective diagnostic biomarkers for SCNSL, and poor progression free survival (PFS) for patients with SCNSL was associated with the increased CSF IL-10 level.