Correlation of IL-6 and TNF-α levels in cerebrospinal fluid and serum in patients with subarachnoid hemorrhage: a meta-analysis

Objective: We conducted this study to explore the correlation of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels in cerebrospinal fluid (CSF) and serum in the patients with subarachnoid hemorrhage (SAH). Methods: Computerized and manual search strategies were performed to retrieve relevant studies. Studies met our inclusion and exclusion criteria were enrolled. Statistical analyses were performed by Comprehensive Meta-analysis 2.0 (Biostat Inc., Englewood, New Jersey, USA). Results: A total of seventeen studies were finally included in this meta-analysis, including 449 SAH patients. The results revealed that IL-6 and TNF-alpha levels in CSF and serum in SAH patients were higher than those in the health control group (CSF: IL-6: SMD = 4.047, 95% CI = 2.651-5.443, P < 0.001; TNF-alpha: SMD = 4.686, 95% CI = 2.475-6.896, P < 0.001; Serum: IL-6: SMD = 2.759, 95% CI = 1.110-4.409, P = 0.001; TNF-alpha: SMD = 1.737, 95% CI = 1.358-2.116, P < 0.001). Further analysis about cerebral vasospasm (CVS) risk indicated that the IL-6 and TNF-alpha levels in CSF and serum in the CVS group were significantly higher than those in the non-CVS group (CSF: IL-6: SMD = 2.025, 95% CI = 1.048-3.003, P < 0.001; TNF-alpha: SMD = 0.969, 95% CI = 0.583-1.355, P < 0.001; Serum: IL-6: SMD = 4.310, 95% CI = 1.271-7.350, P = 0.005; TNF-alpha: SMD = 1.021, 95% CI = 0.549-1.492, P < 0.001). Conclusion: Our evidences suggested that IL-6 and TNF-a levels in CSF and serum may be correlated with SAH, which provides a certain of significant guidance for early diagnosis and monitoring of SAH.