Abstract：
BACKGROUND: Fibrotic hypersensitivity pneumonitis (fHP) shares many features with other fibrotic interstitial lung diseases (ILD), and as a result it can be misdiagnosed as idiopathic pulmonary fibrosis (IPF). We aimed to determine the value of bronchoalveolar lavage (BAL) total cell count (TCC) and lymphocytosis in distinguishing fHP and IPF and to evaluate the best cut-off points discriminating these two fibrotic ILD.
METHODS: A retrospective cohort study of fHP and IPF patients diagnosed between 2005 and 2018 was conducted. Logistic regression was used to evaluate the diagnostic utility of clinical parameters in differentiating between fHP and IPF. Based on the ROC analysis, BAL parameters were evaluated for their diagnostic performance, and optimal diagnostic cut-offs were established.
RESULTS: A total of 136 patients (65 fHP and 71 IPF) were included (mean age 54.97 ± 10.87 vs. 64.00 ± 7.18 years, respectively). BAL TCC and the percentage of lymphocytes were significantly higher in fHP compared to IPF (p < 0.001). BAL lymphocytosis >30% was found in 60% of fHP patients and none of the patients with IPF. The logistic regression revealed that younger age, never smoker status, identified exposure, lower FEV1, higher BAL TCC and higher BAL lymphocytosis increased the probability of fibrotic HP diagnosis. The lymphocytosis >20% increased by 25 times the odds of fibrotic HP diagnosis. The optimal cut-off values to differentiate fibrotic HP from IPF were 15 × 106 for TCC and 21% for BAL lymphocytosis with AUC 0.69 and 0.84, respectively.
CONCLUSIONS: Increased cellularity and lymphocytosis in BAL persist despite lung fibrosis in HP patients and may be used as important discriminators between IPF and fHP.
METHODS: A retrospective cohort study of fHP and IPF patients diagnosed between 2005 and 2018 was conducted. Logistic regression was used to evaluate the diagnostic utility of clinical parameters in differentiating between fHP and IPF. Based on the ROC analysis, BAL parameters were evaluated for their diagnostic performance, and optimal diagnostic cut-offs were established.
RESULTS: A total of 136 patients (65 fHP and 71 IPF) were included (mean age 54.97 ± 10.87 vs. 64.00 ± 7.18 years, respectively). BAL TCC and the percentage of lymphocytes were significantly higher in fHP compared to IPF (p < 0.001). BAL lymphocytosis >30% was found in 60% of fHP patients and none of the patients with IPF. The logistic regression revealed that younger age, never smoker status, identified exposure, lower FEV1, higher BAL TCC and higher BAL lymphocytosis increased the probability of fibrotic HP diagnosis. The lymphocytosis >20% increased by 25 times the odds of fibrotic HP diagnosis. The optimal cut-off values to differentiate fibrotic HP from IPF were 15 × 106 for TCC and 21% for BAL lymphocytosis with AUC 0.69 and 0.84, respectively.
CONCLUSIONS: Increased cellularity and lymphocytosis in BAL persist despite lung fibrosis in HP patients and may be used as important discriminators between IPF and fHP.
摘要：
背景：纤维性过敏性肺炎（fHP）与其他纤维化间质性肺病（ILD）具有许多共同特征，可误诊为特发性肺纤维化(IPF)。我们旨在确定支气管肺泡灌洗（BAL）总细胞计数（TCC）和淋巴细胞增多症在区分fHP和IPF中的价值，并评估区分这两种纤维化ILD的最佳临界点。
方法：对2005年至2018年确诊的fHP和IPF患者进行回顾性队列研究。使用Logistic回归评估临床参数在区分fHP和IPF中的诊断效用。根据ROC分析，评估BAL参数的诊断性能，并建立了最佳诊断界限。
结果：共纳入136例患者（65fHP和71IPF）（平均年龄54.97±10.87vs.64.00±7.18年，分别)。与IPF相比,fHP中的BALTCC和淋巴细胞百分比显著更高(p<0.001)。在60％的fHP患者和IPF患者中均未发现BAL淋巴细胞增多>30％。Logistic回归显示，年龄较小，从不吸烟，确定的暴露，较低的FEV1，较高的BALTCC和较高的BAL淋巴细胞增多增加了纤维化HP诊断的可能性。>20％的淋巴细胞增多增加了25倍的纤维化HP诊断的几率。区分纤维化HP和IPF的最佳截断值TCC为15×106，BAL淋巴细胞增多为21％，AUC分别为0.69和0.84。
结论：尽管HP患者肺纤维化，但BAL中细胞数量和淋巴细胞增多的增加仍然存在，可以用作IPF和fHP之间的重要区别。
方法：对2005年至2018年确诊的fHP和IPF患者进行回顾性队列研究。使用Logistic回归评估临床参数在区分fHP和IPF中的诊断效用。根据ROC分析，评估BAL参数的诊断性能，并建立了最佳诊断界限。
结果：共纳入136例患者（65fHP和71IPF）（平均年龄54.97±10.87vs.64.00±7.18年，分别)。与IPF相比,fHP中的BALTCC和淋巴细胞百分比显著更高(p<0.001)。在60％的fHP患者和IPF患者中均未发现BAL淋巴细胞增多>30％。Logistic回归显示，年龄较小，从不吸烟，确定的暴露，较低的FEV1，较高的BALTCC和较高的BAL淋巴细胞增多增加了纤维化HP诊断的可能性。>20％的淋巴细胞增多增加了25倍的纤维化HP诊断的几率。区分纤维化HP和IPF的最佳截断值TCC为15×106，BAL淋巴细胞增多为21％，AUC分别为0.69和0.84。
结论：尽管HP患者肺纤维化，但BAL中细胞数量和淋巴细胞增多的增加仍然存在，可以用作IPF和fHP之间的重要区别。
