IL6 and infectious meningitis: Meningitis patients had significantly higher levels of blood leukocytes (15.9 (14.3–20.2) vs. 6.3 ((5.2–7.3); p < 0.001), plasma C-reactive protein (237 (74–373) vs. 2 (2–2) mg/l, p < 0.001) and plasma interleukin 6 (43 (13–128) vs. 4.6 (4.6–16.6) pg/ml; p < 0.001) than healthy volunteers (Table 1, Fig 1A, Fig 1B).