Saetta M, Maestrelli P, Turato G, Mapp C E, Milani G, Pivirotto F, Fabbri L M, Di Stefano A
Institute of Occupational Medicine, University of Padova, Italy.
Am J Respir Crit Care Med. 1995 Feb;151(2 Pt 1):489-94. doi: 10.1164/ajrccm.151.2.7842211.
To determine whether the cessation of exposure to isocyanates is associated with structural changes of the airway wall in sensitized subjects, we studied bronchial biopsies from 10 subjects with occupational asthma induced by toluene diisocyanate (TDI). Bronchial challenges with TDI and methacholine were performed and biopsies were taken on two occasions, at diagnosis and 6 to 21 mo after cessation of exposure to TDI. After bronchoscopy, biopsies were formalin-fixed or snap-frozen in liquid nitrogen and then processed for a quantitative histochemical and immunohistochemical analysis. After cessation of exposure, we observed a significant decrease of the sensitivity to TDI (p < 0.05), of the thickness of subepithelial fibrosis (p < 0.007), and of the numbers of subepithelial fibroblasts (p < 0.05), mast cells (p < 0.02), and lymphocytes (p < 0.03) as compared with values at diagnosis. By contrast, the nonspecific bronchial hyperresponsiveness and the numbers of macrophages and eosinophils did not change. In conclusion, in patients with occupational asthma induced by TDI, the cessation of exposure to the sensitizing agent is associated with a reduced thickness of subepithelial fibrosis and with a reduced number of subepithelial fibroblasts, mast cells, and lymphocytes in the bronchial mucosa, suggesting a remodeling of the airway wall with the avoidance of the specific stimulus.
为了确定停止接触异氰酸酯是否与致敏个体气道壁的结构变化有关，我们研究了10例由甲苯二异氰酸酯（TDI）诱发的职业性哮喘患者的支气管活检样本。对患者进行了TDI和乙酰甲胆碱支气管激发试验，并在诊断时以及停止接触TDI后6至21个月这两个时间点采集活检样本。支气管镜检查后，活检样本用福尔马林固定或在液氮中速冻，然后进行定量组织化学和免疫组织化学分析。停止接触后，与诊断时的值相比，我们观察到对TDI的敏感性显著降低（p < 0.05），上皮下纤维化厚度显著降低（p < 0.007），上皮下成纤维细胞数量显著减少（p < 0.05），肥大细胞数量显著减少（p < 0.02），淋巴细胞数量显著减少（p < 0.03）。相比之下，非特异性支气管高反应性以及巨噬细胞和嗜酸性粒细胞的数量没有变化。总之，在由TDI诱发的职业性哮喘患者中，停止接触致敏剂与支气管黏膜上皮下纤维化厚度降低以及上皮下成纤维细胞、肥大细胞和淋巴细胞数量减少有关，这表明避免特定刺激后气道壁发生了重塑。
