Levinson S S, Hobbs G A
Department of Veterans Affairs Medical Center, and the Department of Pathology, University of Louisville, KY 40206, USA.
Arch Pathol Lab Med. 1997 Jul;121(7):678-84.
Studies are divided as to whether or not apolipoprotein A-I (apo A-I) is a better marker for coronary artery disease (CAD) than high-density lipoprotein cholesterol. We hypothesized that the detergent Tween 20, which is thought to expose antigenic sites in apo A-I, would improve automated kit apo A-I assays as a diagnostic marker for CAD.
Apolipoprotein A-I was assayed by two standard automated methods and by the same methods after serum samples and reagents had been treated with Tween 20. Serum samples were obtained from 226 consecutive male patients, age 40-70 years, presenting for angiography, except for defined exclusion characteristics. Patients were categorized into two groups on the basis of stenosis: (1) normal, all vessels <20% stenosis, n = 79, and (2) CAD, at least one vessel >70% stenosis, n = 147. Diagnostic accuracy was assessed by receiver operator characteristic stenosis curves and forward stepwise logistic regression, where adjustment was made for significant possible confounding characteristics and drugs.
The optimal concentration of Tween 20 was found to be 0.5%. Receiver operator characteristic curves showed a greater area for apo A-I with Tween (area = 0.63 to 0.64) as compared to apo A-I without Tween (area = 0.60 to 0.62). Logistic regression indicated that apo A-I with Tween was a significantly better marker than high-density lipoprotein cholesterol. Receiver operator characteristic curves indicated that the ratio of modified apo A-I to apo B gave a significant improvement in area over the ratio of high-density to low-density lipoprotein cholesterol.
Addition of Tween 20 to apo A-I assays improved diagnostic discrimination for CAD. The modified apo A-I assays were better markers than high-density lipoprotein cholesterol, and the ratio of apolipoproteins was significantly better markers than lipoprotein lipids. These findings may explain the discrepancies between studies comparing high-density lipoprotein cholesterol and apo A-I as markers for CAD. Our data suggest that a multicenter effort toward optimizing and clinically validating apo A-I test reagents may be worthwhile.
关于载脂蛋白A-I（apo A-I）是否比高密度脂蛋白胆固醇更适合作为冠状动脉疾病（CAD）的标志物，各项研究结果不一。我们推测，去污剂吐温20被认为可暴露apo A-I中的抗原位点，它会改进自动试剂盒检测apo A-I，使其成为CAD的诊断标志物。
采用两种标准自动方法检测载脂蛋白A-I，并在血清样本和试剂用吐温20处理后，再用相同方法检测。除明确的排除特征外，连续纳入226例年龄40至70岁的男性患者，这些患者因血管造影就诊，采集其血清样本。根据狭窄情况将患者分为两组：（1）正常组，所有血管狭窄<20%，n = 79；（2）CAD组，至少一支血管狭窄>70%，n = 147。通过受试者工作特征狭窄曲线和向前逐步逻辑回归评估诊断准确性，同时对可能的显著混杂特征和药物进行校正。
发现吐温20的最佳浓度为0.5%。受试者工作特征曲线显示，与未加吐温的apo A-I（曲线下面积 = 0.60至0.62）相比，加吐温的apo A-I曲线下面积更大（曲线下面积 = 0.63至0.64）。逻辑回归表明，加吐温的apo A-I是比高密度脂蛋白胆固醇更好的标志物。受试者工作特征曲线表明，改良apo A-I与apo B的比值较高密度脂蛋白与低密度脂蛋白胆固醇的比值，曲线下面积有显著改善。
在apo A-I检测中添加吐温20可提高CAD的诊断鉴别能力。改良的apo A-I检测是比高密度脂蛋白胆固醇更好的标志物，载脂蛋白比值是比脂蛋白脂质更好的标志物。这些发现可能解释了比较高密度脂蛋白胆固醇和apo A-I作为CAD标志物的研究之间的差异。我们的数据表明，多中心努力优化和临床验证apo A-I检测试剂可能是值得的。
