Rossi Heini, Virtala Anna-Maija, Raekallio Marja, Rahkonen Emmi, Rajamäki Minna M, Mykkänen Anna
Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
Front Vet Sci. 2018 Mar 26;5:61. doi: 10.3389/fvets.2018.00061. eCollection 2018.
Most equine lower respiratory diseases present as increased airway neutrophilia, which can be detected in tracheal wash (TW) or bronchoalveolar lavage fluid (BALF) cytology samples. The aim was to compare the TW and BALF results in a population of client-owned horses with and without clinical respiratory disease signs. A secondary aim was to determine the sensitivity (Se) and specificity (Sp) of TW and BALF neutrophilia in detecting respiratory disease. The cutoff values for neutrophils were also evaluated. Retrospective data from 154 horses of various breeds that had been subject to both TW and bronchoalveolar lavage (BAL) sampling at rest during 2009-2015 were used. The horses were divided into three groups based on the presenting signs, physical examination, and endoscopy mucus score. Neutrophil counts of >20% in TW and >5% in BAL were considered abnormal. Cytology results between groups, correlations between TW and BALF cell types, and tracheal mucus score were analyzed. Two graph receiving operating characteristic (ROC) curves of the neutrophil percentage values of TW and BALF were created to determine the optimal cutoff values and to calculate the diagnostic Se and Sp for diagnosing airway inflammation in horses with and without clinical respiratory signs. The Se and Sp of TW and BALF neutrophil percentages were further estimated using a two-test one-population Bayesian latent class model. The two tests showed substantial agreement, and only 17.5% of the horses were classified differently (healthy vs. diseased). The neutrophil percentage was found to correlate between TW and BALF. The Se and Sp of TW were generally higher than for BAL when estimated with area under the curve or Bayesian model. Cutoff values of 17.7% for TW and 7% for BALF were indicated by the ROCs. We conclude that TW is a more sensitive and specific method in our patient population. We suggest that the current neutrophil cutoff values of 20% for TW and 5% for BALF would still be appropriate to use in clinical diagnosis of airway inflammation. However, further studies with other cell types and in other populations are warranted to determine the best sampling method for individual horses.
大多数马的下呼吸道疾病表现为气道嗜中性粒细胞增多，这可在气管冲洗（TW）或支气管肺泡灌洗（BALF）细胞学样本中检测到。目的是比较有和没有临床呼吸道疾病体征的客户拥有马匹群体中TW和BALF的结果。第二个目的是确定TW和BALF嗜中性粒细胞增多在检测呼吸道疾病中的敏感性（Se）和特异性（Sp）。还评估了嗜中性粒细胞的临界值。使用了2009年至2015年期间154匹不同品种的马在静息状态下同时进行TW和支气管肺泡灌洗（BAL）采样的回顾性数据。根据呈现的体征、体格检查和内窥镜检查黏液评分将马分为三组。TW中嗜中性粒细胞计数>20%和BAL中>5%被认为异常。分析了组间的细胞学结果、TW和BALF细胞类型之间的相关性以及气管黏液评分。创建了TW和BALF嗜中性粒细胞百分比值的两条图形接受操作特征（ROC）曲线，以确定最佳临界值，并计算有和没有临床呼吸道体征的马匹诊断气道炎症的诊断Se和Sp。使用双检验单总体贝叶斯潜在类别模型进一步估计TW和BALF嗜中性粒细胞百分比的Se和Sp。两种检验显示出高度一致性，只有17.5%的马被分类不同（健康与患病）。发现TW和BALF之间嗜中性粒细胞百分比相关。当用曲线下面积或贝叶斯模型估计时，TW的Se和Sp通常高于BAL。ROC表明TW的临界值为17.7%，BALF的临界值为7%。我们得出结论，在我们的患者群体中，TW是一种更敏感和特异的方法。我们建议，目前TW的嗜中性粒细胞临界值20%和BALF的5%仍适用于气道炎症的临床诊断。然而，需要对其他细胞类型和其他群体进行进一步研究，以确定针对个体马匹的最佳采样方法。
