Tobacco smoke enhances allergic bronchial sensitization in the guinea pig

Passive smoking has been shown to cause increased incidence of lower respiratory tract infection and wheezing in young children and an inceased risk of childhood asthma. To evaluate possible influence of tobacco smoke on allergic bronchial sensitization we exposed guinea pigs to tobacco smoke in 3 concentrations of clean air (control group) for 8 h on 5 consecutive days (median plasma cotinine 5. 0—25. 4—87, 2 ng/l). The animals were sensitized by repeated inhalation with ovalbumin. Histologic examination at the end of exposure revealed reactive epithelial hyperplasia and regenerative changes as well as inflammatory reaction mainly in the lung periphery, and histamine provocation showed increased bronchial reactivity at the end of tobacco smoke exposure. Sensitization was measured by specific bronchial provocation testing using body plethysmographic measurement of compressed air (CA) and specific anti‐ovalbumin‐antibodies of the IgG 1 ‐subclass in the serum, measured by direct ELISA in ELISA units (EU). The group with the highest tobacco smoke exposure differed significantly in bronchial reactivity on specific bronchial provocation tests (p < 0.005) compared with the control groups and showed elevated unspecific IgG 1 ‐antibody levels indicating enhanced sensitization. We conclude that intensive exposure to tobacco smoke over a short period of 5 d can enhance inhalational allergic sensitization in the guinea pig and might explain the increased incidence of respiratory allergies in child passive smokers.