P3-060: Cerebrospinal fluid markers in dementia with Lewy bodies (DLB) in comparison with Alzheimer′s disease (AD)

Abstract

AD and DLB present with similar clinical features and biological markers to differentiate both disorders are still lacking. Pathologically, most cases with pure DLB exhibit a diffuse plaque-only pathology with rare or absent neocortical neurofibrillary tangles, as opposed to the wide cortical neurofibrillary-tau involvement in AD. We analyzed CSF markers chosen as to reflect some of these underlying pathological differences. CSF samples of 33 cases with probable AD (NINCDS-ADRA criteria) without parkinsonism, 25 cases will all the core features of DLB (Consortium criteria) and 46 age-matched controls were analyzed. Total tau, Ab1–42 amyloid, IL-1b and IL-6 levels were measured by sandwich ELISA using commercially available kits (Innogenetics NV, Belgium and Diaclone Research, France). Tau protein: AD cases had significantly higher levels (500 ± 399 pg/ml, mean ± SD) than DLB cases (213 ± 243) and controls (200 ± 243) (p< 0.0001). There were no differences between DLB and control groups. The most efficient cutoff point (250 pg/ml) provided a 76% specificity to distinguish AD and DLB cases. b-amyloid: AD (348 ± 309 pg/ml) and DLB cases (320 ± 233) had lower b-amyloid levels than controls (462 ± 352) but the differences did not reach statistical significance. The combination of tau/ b-amyloid levels provided the best value to differenciate AD vs controls (cut-off point 0.5, sensitivity 82,5%, specificity 75%) but was worse than tau values alone to discriminate between AD and DLB. Interleukine 1b: IL-1b levels in the three groups were within the lowest values of the standard curve. There were no significant differences among AD (2.17 ± 3.00 pgr/ml), DLB (2.60 ± 2.97) cases and controls (2.02 ± 3.28). Interleukine 6: AD (7.14 ± 5.74 pgr/ml) and DLB (6.14 ± 5.00) cases showed slightly higher IL-6 levels than controls (4.96 ± 4.72) but the differences among the three groups were not significant. Tau levels in CSF may contribute to the clinical distinction between AD and DLB. b-amyloid CSF levels are similar in AD and DLB cases and tend to be lower than in controls. Interleukine CSF concentrations do not distinguish between both dementia disord.