Cerebrospinal fluid ferritin in brain necrosis: evidence for local synthesis.

Ferritin was measured in cerebrospinal fluid (CSF) and serum of an unselected neurological population. An increase in CSF ferritin was found to be associated with pathological processes in which there was either necrosis or haemorrhage involving the brain. There was no correlation between the CSF and serum concentrations of ferritin in the reference population. Neither was there any correlation between CSF ferritin and CSF albumin in the reference population. After subarachnoid haemorrhage, intrathecal production of ferritin was found to occur since in some patients the concentration of ferritin in CSF was higher than that of homologous serum. Even in the reference population the concentration of ferritin found in the CSF was much higher than could be explained by passive transfer across the blood-CSF barrier. Therefore local synthesis of ferritin by brain cells occurs even under normal circumstances.