Effects of cigarette smoking on IgE-mediated allergy in elderly patients with asthma

The influence of cigarette smoking on the pathophysiology of asthma in the elderly remains controversial. In this study, the inluence of cigarette smoking on IgE - mediated allergy including the generation of leukotrienes B4 (LTB4) and C4 (LTC4) was examined in forty asthmatics over the age of 70 years (20 ex-smokers and 20 never-smokers), and 20 patients with pulmonary emphysema over age 70 (all ex - smokers). The frequency of patients with serum IgE more than 200 IU/ml was significantly larger in smoking asthmatics than in non - smoking asthmatics. The incidence of patients with positive RAST score for inhalant allergens, was also significantly higher in patients with a history of smoking than in those without a smoking history. There were no significant differences in the frequency of patients with positive RAST and those with serum IgE more than 200 IU/ml between non-smoking asthmatics and patients with pulmonary emphysema. The generation of leukotriene B4 (LTB4) by leukocytes was significantly more increased in ex-smokers than in never-smokers in the elderly asthmatics. The results suggest the possibility that cigarette smoking enhances IgE - mediated allergy in elderly patients with asthma.

高齢者喘息の病態に対する喫煙の影響については,なお不明な点が多い｡本研究では,70歳以上の気管支喘息40例(喫煙歴20年以上の症例20例,非喫煙症例20例)および70歳以上の肺気腫20例(全例喫煙者)を対象に,IgE-mediatedallergy(LTB4,LTC4の産生を含む)に対する喫煙の影響について検討した｡血清IgE値が200IU/ml以 上を示す症例の頻度は,喘息の喫煙例で非喫煙例や肺気腫症例と比べ有意に高い値を示した｡吸入抗原に対する特異的IgE抗体が陽性を示す症例の頻度は,喘息の喫煙例で非喫煙例や肺気腫に比べ有意に高い値を示した｡しかし,血清IgEが200IU/ml以上の症例の頻度およびRAST陽性例の頻度は,喘息の非喫煙例と肺気腫例の間には有意 の差は見られなかった｡LTB4の産生は,喘息の喫煙例で,非喫煙例と比べ有意の亢進が見られた｡また,肺気腫例では,喘息の非喫煙例に比べ,有意に高い産生が見られた｡しかし,LTC4の産生には喘息の喫煙例,非喫煙例,肺気腫例の間に有意の差は見られなかった｡