Serum levels of surfactant proteins A and D are useful biomarkers for interstitial lung disease in patients with progressive systemic sclerosis
Serum levels of surfactant proteins A and D are useful biomarkers for interstitial lung disease in patients with progressive systemic sclerosis
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DOI：
10.1164/ajrccm.162.1.9903014
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发表时间：
2000-07-01
影响因子：
24.7
通讯作者：
Abe, S
中科院分区：
文献类型：
--
作者：
Takahashi, H;Kuroki, Y;Abe, S
为了寻找一种侵袭性小、肺特异性强的临床生物标志物，我们采用夹心酶联免疫吸附试验检测了42例进行性系统性硬化症（PSS）患者血清表面活性蛋白A和D（SP-A和SP-D）水平，以评价其与间质性肺疾病（ILD）相关的意义，并评估其诊断价值。根据胸部计算机断层扫描（CT）结果将患者分为两组：30例ILD患者（CT阳性ILD组）和12例无任何肺部异常的患者（CT阴性ILD组）。CT阳性ILD组进一步分为两组：24例胸部平片可检出ILD（X线阳性ILD组）和6例无异常ILD（X线阴性ILD组）。CT阳性ILD组血清SP-A、SP-D水平显著高于CT阴性ILD组。X线阳性ILD组中的这些指标也显著高于CT阴性ILD组。在X线阴性ILD组中，它们的水平高于CT阴性ILD组。接下来我们评估了SP-A、SP-D和X线在CT上检测ILD的敏感性和特异性。SP-D敏感性高（77%），X线敏感性高（80%），SP-A敏感性低（33%）。值得注意的是，X射线阴性ILD组6例患者中有5例显示SP-D浓度超过其临界水平，从而证明SP-D测定有助于检测X射线忽略的ILD。此外，X射线和SP-D的组合将灵敏度显著提高到97%。SP-A、SP-D和X线对CT阴性ILD组的特异性分别为100%、83%和100%。总之，本研究表明，血清SP-A和SP-D水平升高很好地反映了ILD的存在，SP-D和X线联合检查有助于降低临床医生忽视ILD并发PSS的风险，尽管需要在另一组受试者中重复检查以确认这些适应症。
To find a less-invasive and lung-specific clinical biomarker, we measured serum levels of surfactant proteins A and D (SP-A and SP-D) by sandwich enzyme-linked immunosorbent assays in 42 patients with progressive systemic sclerosis (PSS) to evaluate their significance in relation to the presence of interstitial lung disease (ILD) and to assess their diagnostic merits. The patients were divided into two groups based on findings by chest computed tomography (CT): 30 patients with ILD (CT-positive ILD group), and 12 patients without any lung abnormalities (CT-negative ILD group). The CT-positive ILD group was further divided into two groups: 24 patients with ILD detectable by chest plain radiography (X-ray-positive ILD group) and six patients with ILD showing no abnormality (X-ray-negative ILD group). The levels of SP-A and SP-D in sera were significantly higher in the CT-positive ILD group than in the CT-negative ILD group. They were also significantly higher in the X-ray-positive ILD group than in the CT-negative ILD group. In the X-ray-negative ILD group, their levels were higher than those of the CT-negative ILD group. We next estimated sensitivity and specificity of SP-A, SP-D, and X-ray for detecting ILD on CT. Sensitivity of SP-D was high (77%) as well as that of X-ray (80%), whereas SP-A showed a low sensitivity (33%). Remarkably, five of six patients in the X-ray-negative ILD group showed SP-D concentrations over its cut-off level, thereby demonstrating that an SP-D assay contributes to the detection of ILD overlooked by X-ray. Moreover, a combination of X-ray and SP-D dramatically increases sensitivity to 97%. Specificity of SP-A, SP-D, and X-ray to the CT-negative ILD group was 100%, 83%, and 100%, respectively. In conclusion, this study indicates that elevated levels of serum SP-A and SP-D reflect well the presence of ILD and that the combination of SP-D and X-ray contributes to reduce the risk of clinicians overlooking ILD complicated by PSS, although a repetition in another set of subjects is needed to confirm these indications.