Neurotrophin levels in cerebrospinal fluid of adult patients with meningitis and encephalitis

Background: The data on cerebrospinal fluid (CSF) levels of neurotrophins (NTs) in patients with meningoencephalitis are scarce, especially in adult patients. Methods: We measured CSF levels of NTs such as nerve growth factor (NGF), brain-derived neurotrophic factor, and neurotrophin-3 (NT-3) in adult patients with various meningitis (n = 10) and encephalitis (n = 10) in both acute phase and recovery phase and adult control subjects (n = 21) by the enzyme-linked immunosorbent assay for NTs. Results: Data show that NGF and NT-3 CSF levels were markedly elevated in the patient group in the acute phase compared with non-neurological controls (p < 0.001 and p < 0.05, respectively) and later returned to the levels of controls. Most intriguingly, we only recognized a significant correlation between NGF and NT-3 CSF levels in the patients in the acute phase. Conclusion: Such strong correlation of NGF and NT-3 CSF levels strongly suggests that in adult patients, some common regulatory mechanism(s) might be present among various kinds of NTs to cope with central nervous system infection.