脑脊液中β淀粉样蛋白检测对老年期痴呆的诊断意义

Detection of β amyloid protein in CSF of senile dementia patients and its significance of diagnosis

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 (EL ISA)检测 2 4例 AD患者、14例 VD患者及 30例正常对照者 CSF中 Aβ1 - 4 0 和 Aβ1 - 4 2 的浓度并计算其比值。结果 (1) AD和 VD患者 CSF中 Aβ1 - 4 2 水平明显低于正常对照组 (P<0 .0 5 ) ,Aβ1 - 4 0 则无显著差异 ;(2 )正常对照组 Aβ比值 (Aβ1 - 4 0 / Aβ1 - 4 2 )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 13.5 1± 11.86和 12 .6 9± 7.41) ,差异有显著性 (均 P<0 .0 5 ) ;(3)以 Aβ比值 10 .4为临界点 ,诊断老年期痴呆的敏感性为 6 0 .5 0 % (2 3/ 38) ,特异性为 88.46 % (2 3/2 6 )。结论 AD及 VD患者 CSF中 Aβ1 - 4 2 水平较低 ,Aβ1 - 4 0 / Aβ1 - 4 2 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 。

Objective To study the levels of β amyloid protein(Aβ/βA 4) in cerebrospinal fluid(CSF) of patients with Alzheimer's disease(AD) and vascular dementia(VD) and its significance of diagnosis.Methods The levels of Aβ 1 40 and Aβ 1 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 Aβ 1 42 in CSF of AD and VD patients were significantly lower than NC group ( P <0.05). No difference in Aβ 1 40 levels was observed among these groups;(2)The Aβ ratio (Aβ 1 40 /Aβ 1 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 Aβ 1 42 , and the ratio of Aβ 1 40 /Aβ 1 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.