IL6 and infectious encephalitis: Subgroup analysis results are consistent and show that in both autoimmune and infectious encephalitis, CSF concentration of IL-6 is higher than controls (SMD (autoimmune), 1.90; 95% CI, 0.71–3.90; P < 0.01; SMD (infectious), 1.28; 95% CI, 0.75–1.80; P < 0.01).