Purpose: The pathological diagnosis of primary central nervous system lymphoma (PCNSL) by stereotactic brain biopsy and craniotomy is not often applicable due to the high cost and associated complications. In recent years, some biomarkers in cerebrospinal fluid (CSF), including interleukin 10 (IL-10), microRNAs, CXC chemokine ligand 13 (CXCL13), have been reported to be associated with PCNSL. However, this conclusion was controversial. Therefore, this study was to test whether Th17 cell-related cytokines could be used to distinguish PCNSL from other brain tumors.
Patients and Methods: Th17 cell-related cytokines in CSF were measured in 108 patients with intracranial tumors, which included 66 PCNSL patients and 42 patients with other types of brain tumors. A receiver-operating characteristic (ROC) curve was utilized to analyze the diagnostic value of the cytokines based on the area under the curve (AUC).
Results: The CSF IL-10 level and IL-10/IL-6 ratios were significantly higher in PCNSL than in the other brain tumors (58.2 pg/mL VS 1.5 pg/mL, p =0.001; 24.3 VS 0.6, p =0.001). When the cutoff level of IL-10 was set at 8.3 pg/mL, its sensitivity and specificity for diagnosing PCNSL were 59.0% and 98%, respectively. The CSF IL-10 levels over 5pg/mL (+LR 12.3) were of significant value for the diagnosis of PCNSL. These parameters are highly valuable in PCNSL diagnosis, but their sensitivity is less valuable. The sensitivity of IL-4 and IL-17A, the ratio of mature lymphocytes and the monocytes/macrophages ratio in CSF were relatively high. In combination, the sensitivity increased by 15% and the specificity remained above 85%. The best combination was IL-10 and IL-17A, whose sensitivity was 70% and specificity was 96%.
Conclusion: The CSF level of IL-10 is a useful diagnostic biomarker in patients with PCNSL. The CSF levels of IL-4, IL-17A, mature lymphocytes and monocytes/macrophages can be used to increase the diagnostic value of CSF IL-10 level and IL-10/IL-6 ratio.
Keywords: primary central nervous system lymphoma, diagnosis, cytokines, IL-10