Centre intégré universitaire de santé et des services sociaux du Nord-de-l'Île-de-Montréal, Hôpital du Sacré-Cœur de Montréal, Université de Montréal, Montréal, Quebec, Canada.
Centre intégré universitaire de santé et des services sociaux du Nord-de-l'Île-de-Montréal, Hôpital du Sacré-Cœur de Montréal, Université de Montréal, Montréal, Quebec, Canada.
J Allergy Clin Immunol Pract. 2017 Sep-Oct;5(5):1371-1377.e1. doi: 10.1016/j.jaip.2017.02.001. Epub 2017 Mar 9.
The assessment of airway responsiveness and inflammation is key to the investigation of occupational asthma (OA).
We sought to assess and compare the diagnostic accuracies of the blood and sputum eosinophil counts and the methacholine challenge for the diagnosis of OA.
We conducted a retrospective study assessing 618 patients who underwent specific inhalation challenges (SICs) for symptoms suggestive of OA between 2000 and 2015. A sputum induction and a methacholine challenge were performed before and after SICs. Blood samples were collected in all subjects before the SICs and in 100 subjects before and after SICs. The diagnostic accuracies of blood and sputum eosinophil counts and methacholine challenge were calculated for diagnosing OA.
The change in blood eosinophil count failed to differentiate workers with positive and negative SICs. The change in sputum eosinophil counts induced by the exposure to the offending agent had the highest diagnostic accuracy (receiver operating characteristic area under the curve: 86% [95% confidence interval: 0.8-0.9, P < .001]) for diagnosing OA compared with changes in concentration of methacholine inducing a 20% fall in forced expiratory volume in 1 second (PC) and blood eosinophils. Combining a 2-fold or greater decrease in PC or a 3% or greater increase in sputum eosinophil count achieved a sensitivity of 84% and a specificity of 74% with a negative predictive value of 91% for the diagnosis of OA.
Blood eosinophil counts do not appear to be an effective aid for diagnosing OA. The performance of both sputum cell count analysis and a methacholine challenge before and after exposure to the offending agent may represent an effective alternative in diagnosing OA when SICs are unavailable.
气道反应性和炎症的评估是职业性哮喘（OA）研究的关键。
我们旨在评估和比较血液和痰嗜酸性粒细胞计数以及乙酰甲胆碱挑战对 OA 诊断的准确性。
我们进行了一项回顾性研究，评估了 2000 年至 2015 年间因疑似 OA 症状而接受特定吸入性挑战（SIC）的 618 例患者。在 SIC 前后进行了痰诱导和乙酰甲胆碱挑战。所有患者在 SIC 前和 100 例患者在 SIC 前和后采集了血液样本。计算了血液和痰嗜酸性粒细胞计数以及乙酰甲胆碱挑战对诊断 OA 的诊断准确性。
血液嗜酸性粒细胞计数的变化未能区分 SIC 阳性和阴性的工人。暴露于致病剂后诱导的痰嗜酸性粒细胞计数的变化具有最高的诊断准确性（接受者操作特征曲线下面积：86%[95%置信区间：0.8-0.9，P<.001]），用于诊断 OA，与乙酰甲胆碱浓度变化相比，可诱导用力呼气量在 1 秒内下降 20%（PC）和血液嗜酸性粒细胞。联合 PC 下降 2 倍或以上或痰嗜酸性粒细胞计数增加 3%或以上，对诊断 OA 的敏感性为 84%，特异性为 74%，阴性预测值为 91%。
血液嗜酸性粒细胞计数似乎不是诊断 OA 的有效辅助手段。当无法进行 SIC 时，在暴露于致病剂前后进行痰细胞计数分析和乙酰甲胆碱挑战可能是诊断 OA 的有效替代方法。
