Aiko Masunaga1, Tamiko Takemura2, Hidenori Ichiyasu3, Emi Migiyama1, Yuko Horio1, Sho Saeki1, Susumu Hirosako1, Takeshi Mori4, Makoto Suzuki4, Hirotsugu Kohrogi1, Takuro Sakagami1. 1. Department of Respiratory Medicine, Kumamoto University Hospital, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan. 2. Department of Pathology, Kanagawa Cardiovascular and Respiratory Center, Kanagawa, 236-0051, Japan. 3. Department of Respiratory Medicine, Kumamoto University Hospital, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan. Electronic address: ichiyasu@kumamoto-u.ac.jp. 4. Department of Thoracic Surgery, Kumamoto University Hospital, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan.
Abstract
BACKGROUND: Smoking causes an influx of inflammatory cells including Langerhans cells (LCs) into the airways and lung parenchyma, thus inducing histological changes, such as emphysema and fibrosis. We examined the distribution and quantity of Langerhans cells in relation to clinical and pathological findings and explored the association between smoking and accumulation of Langerhans cells in the respiratory bronchioles. METHODS: Fifty-three patients who underwent lung resection for primary diseases, including lung cancer, were recruited. Histological and immunohistochemistry analyses were utilized to identify CD1a-positive Langerhans cells in peripheral lung specimens separated from primary lesions. Clinical characteristics, pathological changes, and distribution of CD1a-positive Langerhans cells distribution were assessed. RESULTS: Of the 53 patients, 35 were smokers and 18 were non-smokers. The number of Langerhans cells in the respiratory bronchioles was significantly increased in smokers as compared to that in non-smokers (p < 0.001). The number of Langerhans cells in smokers was significantly higher in patients with mild emphysema than in those without emphysema (p < 0.01). The high-LC group showed more frequent smoking-related histological changes, such as respiratory bronchiolitis, parenchymal fibrosis, accumulation of macrophages, and smoking-related interstitial fibrosis, than the low-LC group. However, there were no differences in the smoking indices and pulmonary functions of the groups. CONCLUSIONS: Selective accumulation of Langerhans cells in the respiratory bronchioles of smokers may lead to the development of smoking-related pathological changes.
BACKGROUND: Smoking causes an influx of inflammatory cells including Langerhans cells (LCs) into the airways and lung parenchyma, thus inducing histological changes, such as emphysema and fibrosis. We examined the distribution and quantity of Langerhans cells in relation to clinical and pathological findings and explored the association between smoking and accumulation of Langerhans cells in the respiratory bronchioles. METHODS: Fifty-three patients who underwent lung resection for primary diseases, including lung cancer, were recruited. Histological and immunohistochemistry analyses were utilized to identify CD1a-positive Langerhans cells in peripheral lung specimens separated from primary lesions. Clinical characteristics, pathological changes, and distribution of CD1a-positive Langerhans cells distribution were assessed. RESULTS: Of the 53 patients, 35 were smokers and 18 were non-smokers. The number of Langerhans cells in the respiratory bronchioles was significantly increased in smokers as compared to that in non-smokers (p < 0.001). The number of Langerhans cells in smokers was significantly higher in patients with mild emphysema than in those without emphysema (p < 0.01). The high-LC group showed more frequent smoking-related histological changes, such as respiratory bronchiolitis, parenchymal fibrosis, accumulation of macrophages, and smoking-related interstitial fibrosis, than the low-LC group. However, there were no differences in the smoking indices and pulmonary functions of the groups. CONCLUSIONS: Selective accumulation of Langerhans cells in the respiratory bronchioles of smokers may lead to the development of smoking-related pathological changes.