Lysozyme activity in cerebrospinal fluid. Studies in inflammatory and non-inflammatory CNS disorders

Lysozyme activity was measured in cerebrospinal fluid (CSF) from 114 patients with inflammatory (bacterial and serous meningitis, polyradiculitis, encephalitis) and non-inflammatory (multiple sclerosis, CNS tumors, cerebral vascular diseases) CNS diseases. Highly elevated values were found consistently in patients with bacterial meningitis. Elevated values were found also in patients with encephalitis, polyradiculitis, multiple sclerosis and CNS tumors, but a considerable overlapping between these groups and normal controls precludes the use of CSF lysozyme measurements as a diagnostic aid in the latter disease groups. Simultaneous measurements of lysozyme, albumin and IgG in CSF and serum suggested that the mechanism for increased CSF lysozyme values in bacterial meningitis is mainly a breakdown of the blood/brain barrier, whereas the increased CSF lysozyme values in the remaining groups of patients are more likely caused by production of lysozyme by cells within the meninges (neutrophilic granulocytes, monocytes?).