Department of Molecular and Internal Medicine, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan.
Respiration. 2011;82(1):10-8. doi: 10.1159/000324539. Epub 2011 Apr 7.
Recent clinical studies have suggested that serum surfactant protein (SP) A, SP-D and Krebs von den Lungen-6 (KL-6) are potential biomarkers for interstitial lung diseases. Serum levels of SP-A and SP-D have also been found to be elevated in chronic obstructive pulmonary disease (COPD), but their significance has not been evaluated or compared in induced sputum samples obtained directly from the airways.
A sequential sputum analysis was conducted to assess the value of SP-A, SP-D and KL-6 levels in COPD.
The study material consisted of induced sputum samples from 61 subjects, 28 with COPD and 33 with prolonged cough (cough lasting >3 weeks and normal spirometry). Sputum was collected in 3 fractions (3 periods of 5 min each). Sputum levels of these proteins were measured, and receiver operating characteristic curve analysis was carried out to evaluate the sensitivity, specificity and area under the curve (AUC) for each fraction.
The levels of SP-A, SP-D and KL-6 were higher in patients with COPD than in those with prolonged cough in each of the fractions. Sputum levels of these proteins correlated inversely with obstruction and positively with ageing, smoking history, sputum macrophages and eosinophils. Sputum fractionation had a relatively minor effect on the levels and AUC of these proteins.
Sequential sputum analysis from 3 consecutive fractions indicated a significant difference in the levels of SP-A, SP-D and KL-6 between COPD and prolonged cough. However, sputum fractionation itself had a relatively minor effect on the levels of these proteins.
最近的临床研究表明，血清表面活性蛋白（SP）A、SP-D 和 Krebs von den Lungen-6（KL-6）是间质性肺疾病的潜在生物标志物。在慢性阻塞性肺疾病（COPD）中也发现血清 SP-A 和 SP-D 水平升高，但它们在直接从气道获得的诱导痰样本中的意义尚未得到评估或比较。
进行了连续的痰分析，以评估 SP-A、SP-D 和 KL-6 水平在 COPD 中的价值。
研究材料包括 61 名受试者的诱导痰样本，其中 28 名患有 COPD，33 名患有持续性咳嗽（咳嗽持续>3 周且肺功能正常）。痰液采集分为 3 个部分（每个部分 5 分钟）。测量这些蛋白质的痰水平，并进行接收者操作特征曲线分析，以评估每个部分的敏感性、特异性和曲线下面积（AUC）。
在每个部分中，COPD 患者的 SP-A、SP-D 和 KL-6 水平均高于持续性咳嗽患者。这些蛋白质的痰水平与阻塞呈负相关，与年龄、吸烟史、痰巨噬细胞和嗜酸性粒细胞呈正相关。痰分级对这些蛋白质的水平和 AUC 影响相对较小。
来自 3 个连续部分的连续痰分析表明，COPD 和持续性咳嗽之间 SP-A、SP-D 和 KL-6 的水平存在显著差异。然而，痰分级本身对这些蛋白质的水平影响相对较小。
