S-100 PROTEIN-CONCENTRATION IN THE CEREBROSPINAL-FLUID OF PATIENTS WITH CREUTZFELDT-JAKOB-DISEASE

We evaluated S-100 levels in paired cerebrospinal fluid (CSF) and seru m samples in a group of 135 patients referred to the German Creutzfeld t-Jakob disease (CJD) surveillance unit from June 1993 to May 1995. Th e patients were seen in a prospective case control study. The diagnosi s of probable CJD during life was made in any patient presenting with rapidly progressive dementia of less than 2 years' duration, typical p eriodic sharp wave complexes (PSWCs) in the EEG and at least two of th e following findings: myoclonus, visual/or cerebellar symptoms, pyrami dal and/or extrapyramidal signs and/or akinetic mutism. Patients prese nting with the above clinical signs and symptoms but without PSWCs wer e classified as possible, while those with a dementia of a duration ex ceeding 2 years and without PSWCs were classified as other. S-100 was determined in paired CSF and serum samples by a commercially available enzyme-linked immunosorbent assay. In a group of 76 patients with def inite and probable CJD, S-100 concentration (median 25 ng/ml, range 2- 117) in CSF was significantly higher (P < 0.0001) than in 32 patients diagnosed as other (median 4 ng/ml, range 1-19). Serum levels of S-100 were below 0.5 ng/ml in all groups. At a cut-off of 8 ng/ml an optimu m sensitivity of 84.2% with a specificity of 90.6% for the diagnosis o f CJD by the determination of S-100 in CSF is obtained. S-100 levels e xceeding 8 ng/ml in CSF support the diagnosis of CJD in any patient pr esenting with rapidly progressive dementia.