Intrathecal production of interleukin-12 and gamma interferon in patients with bacterial meningitis

Abstract

To assess the role of interleukin-12 (IL-12) and gamma interferon (IFN- γ) in children with bacterial meningitis, bioactive IL-12 (p70) and the inactive subunit p40 and IFN-γ were measured in serum and cerebrospinal fluid (CSF) from 35 children with bacterial meningitis and 10 control subjects. The production of IFN-γ is induced by IL-12 with tumor necrosis factor alpha (TNF-α) as a costimulator and inhibited by IL-10. CSF concentrations of IL-12 p40 as well as those of IFN-γ were markedly elevated, whereas IL-12 p70 was hardly detectable. Detectable CSF levels of IFN-γ correlated positively with IL-12 p40 (r = 0.40, P = 0.02) and TNF-α (r = 0.46, P = 0.04) but not with IL-6, IL-8, or IL-10. In contrast to CSF levels of TNF-α, IL-12, and IL-10, those of IFN-γ were significantly higher in patients with pneumococcal meningitis than in children with meningitis caused by Haemophilus influenzae and Neisseria meningitidis, presumably because of a high CSF TNF-α/IL-10 ratio in the former. We suggest that IL- 12- and TNF-α-induced IFN-γ production may contribute to the natural immunity against microorganisms in the CSF compartment during the acute phase of bacterial meningitis.