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.