脑脊液中β淀粉样蛋白检测对老年期痴呆的诊断意义

摘要

Objective　To study the levels of β amyloid protein(Aβ/βA4) in cerebrospinal fluid(CSF) of patients with Alzheimer's disease(AD) and vascular dementia(VD) and its significance of diagnosis.Methods　The levels of Aβ1-40 and Aβ1-42 in CSF of 24 patients with AD, 14 patients with VD and 30 normal controls(NC) were detected by enzyme-linked immunosorbent assays(ELISA).Results　(1)The levels of Aβ1-42 in CSF of AD and VD patients were significantly lower than NC group (P<0.05). No difference in Aβ1-40 levels was observed among these groups;(2)The Aβ ratio (Aβ1-40/Aβ1-42) was constant in NC group (4.70±2.85), but the Aβ ratio in AD and VD patients was significantly higher than NC group (13.51±11.86, 12.69±7.41 respectively),the diffe-rence had significance (P<0.05);(3)If using the Aβ ratio 10.4 as the cut-off value, the sensitivity of senile dementia was 60.50%(23/38), and the specificity was 88.46%(23/26).Conclusion　AD and VD patients had significantly decreased level of Aβ1-42, and the ratio of Aβ1-40/Aβ1-42 was significantly higher than NC group. The Aβ ratio in CSF was provided in the diagnosis of senile dementia, it had higher specificity and sensibility in clinic.%目的　研究阿尔茨海默病（AD）和血管性痴呆（VD）患者脑脊液(CSF)中β淀粉样蛋白（Aβ或βA4）的含量及其诊断意义。方法　采用酶联免疫吸附法（ELISA）检测24例AD患者、14例VD患者及30例正常对照者CSF中Aβ1-40和Aβ1-42的浓度并计算其比值。结果　(1)AD和VD患者CSF中Aβ1-42水平明显低于正常对照组（P<0.05），Aβ1-40则无显著差异；(2)正常对照组Aβ比值（Aβ1-40/Aβ1-42）较稳定（4.70±2.85），而AD和VD患者Aβ比值高于正常对照组（分别为13.51±11.86和12.69±7.41），差异有显著性（均P<0.05）；(3)以Aβ比值10.4为临界点，诊断老年期痴呆的敏感性为60.50%（23/38），特异性为88.46%（23/26）。结论　AD及VD患者CSF中Aβ1-42水平较低，Aβ1-40/Aβ1-42比值明显高于正常对照组；CSF Aβ比值用于诊断老年期痴呆，具有较高的特异性和敏感性，临床上有一定的应用及推广价值。