CSF interleukin 6 is a useful marker to distinguish pseudotumoral CNS inflammatory diseases from primary CNS lymphoma

• DOI: 10.1007/s00415-021-10453-5
• Publication Date: 2021-02-20T17:07:55Z
• Authors: Aurelian Ungureanu; Magali Le Garff-T...; Myrto Costopoulos; Timothée Parratte; Abdelmalek Brinet; Hélène Durand; Claude Gaultier; Remy Hurstel; Isabelle Alamome; François Sellal; Guido Ahle
• Keywords: Central Nervous System Neoplasms; Diagnosis, Differential; 03 medical and health sciences; 0302 clinical medicine; Lymphoma; Interleukin-6; Biomarkers, Tumor; Humans; Granuloma, Plasma Cell; Retrospective Studies; 3. Good health

Interleukin 6 (IL-6) is a pleomorphic cytokine that can be found in the cerebrospinal fluid (CSF) in a wide spectrum of inflammatory pathologies of the central nervous system (CNS).Our aim was to characterize the diagnostic significance of CSF IL-6 among various CNS inflammatory diseases with pseudotumoral lesions (CNSID) and primary CNS lymphoma (PCNSL).We retrospectively analyzed the CSF IL-6 concentrations in 43 consecutive patients with suspected PCNSL. A total of 28 patients were positively diagnosed with PCNSL and 15 with CNSID. We verified the results with CSF IL-10, an established biomarker for PCNSL.In the PCNSL group, the median CSF IL-6 concentration was 8 pg/ml, interquartile range (IQR) 5-18.5. For the patients with CNSID, the median concentration was 70 pg/ml, IQR 5-1368. A group comparison showed significantly higher CSF IL-6 levels in patients with CNSID than in those with PCNSL (p = 0.032). Moreover, IL-6 was correlated with CSF cell count in the CNSID group (r = 0.56, p = 0.028), but not in the PCNSL group (r = 0.3, p = 0.13). We found significantly higher CSF IL-10 levels in patients with PCNSL than in patients with CNS inflammatory lesions (p < 0.001).Our study suggests that CSF IL-6 levels could represent, in addition to CSF IL-10, a useful biomarker in the differential diagnosis of CNSID and suspected PCNSL.