Elevated Serum IL-17A but not IL-6 in Glioma Versus Meningioma and Schwannoma

BACKGROUND: There is a Th1/Th2 cytokine imbalance and expression of IL-17 in patients with brain tumours. We aimed to compare the levels of IL-17A and IL-6 in sera of glioma, meningioma and schwannoma patients as well as in healthy individuals. MATERIALS AND METHODS: IL-17A and IL-6 levels were measured in sera of 38 glioma, 24 meningioma and 18 schwannoma patients for comparison with 26 healthy controls by commercial ELISA assays. RESULTS: We observed an increase in the IL-17A in 30% of glioma patients while only 4% and 5.5% of meningioma and schwannoma patients and none of the healthy controls showed elevated IL-17A in their sera (0.29 ± 0.54, 0.03 ± 0.15 and 0.16 ± 0.68 vs. 0.00 ± 0.00 pg/ml; p=0.01, p=0.01 and p=0.001, respectively). There was also a significant decrease in the level of IL-6 in glioma patients compared to healthy controls (2.34 ± 4.35 vs. 4.67 ± 4.32 pg/ml; p=0.01). There was a direct correlation between the level of IL-17A and age in glioma patients (p=0.005). Glioma patients over 30 years of age had higher IL-17A and lower IL-6 in their sera compared to the young patients. In addition, a non-significant grade-specific inverse trend between IL-17A and IL-6 was observed in glioma patients, where high-grade gliomas had higher IL-17A and lower IL-6. CONCLUSIONS: Our data suggest a Th17 mediated inflammatory response in the pathogenesis of glioma. Moreover, tuning of IL-6 and IL-17A inflammatory cytokines occurs during progression of glioma. IL-17A may be a potential biomarker and/or immunotherapeutic target in glioma cases.