INCREASED CEREBROSPINAL-FLUID LEVELS OF NEUROFILAMENT PROTEIN IN PROGRESSIVE SUPRANUCLEAR PALSY AND MULTIPLE-SYSTEM ATROPHY COMPARED WITH PARKINSONS-DISEASE

More reliable tools are needed for the differentiation of Parkinson's disease (PD) from other parkinsonian disorders. The neurofilament prot ein (NFL) and the glial fibrillary acidic protein (GFAP) are main stru ctural proteins of axons and Fibrillary astroglial cells, By using enz yme-linked immunosorbent assays, these proteins were quantified in the cerebrospinal fluid (CSF) of 49 patients referred to the Department o f Neurology for diagnostic consideration or treatment of parkinsonism of different etiologies, All patients were first diagnostically evalua ted by strict clinical criteria. The procedure included a neurologic a nd neuro-ophthalmologic examination as well as computed tomography or magnetic resonance imaging. These were performed independently and in advance of the CSF analysis. A total of 19 patients were diagnosed as having PD, 12 had progressive supranuclear palsy (PSP), and 10 had mul tiple-system atrophy (MSA). Eight were diagnosed as having other disea ses, such as arteriosclerotic parkinsonism and undefined parkinsonian syndromes. The content of NFL was significantly higher both in the PSP group (p < 0.001) and in the MSA group (p < 0.0001) compared with the PD group. The high values of NFL indicate an ongoing neuronal degener ation affecting mainly the axonal compartment in the PSP and MSA group s, whereas there was no difference in glial involvement as measured by GFAP in the PD, PSP, and MSA groups. There was a relation between hig h CSF levels of NFL in the various patient groups and the occurrence o f pyramidal symptoms (p < 0.001), possibly reflecting the axonal damag e to the corticospinal tract. Furthermore, mortality at 24-month follo w up was associated with high NFL levels (p < 0.01). We conclude that analysis of NFL in CSF may become useful in the differential diagnosis of parkinsonian syndromes.