Passive smoking increases allergy

The dangers of passive smoking have been discussed widely and it has become commonplace for smoking to be banned in public places in many countries. Several studies have examined allergic responses in the children of mothers who smoke, with particularly strong evidence indicating that in children with asthma, there is a link between passive smoking and disease severity. However, the role of passive smoking in atopic sensitization is more controversial. A recent study by Rumold and colleagues from the University of California School of Medicine, USA has demonstrated that exposure of mice to passive smoke can augment primary sensitization to an inhaled innocuous protein. Levels of IgE and IgG1 were raised, and there was an influx of eosinophils into the lungs and increased production of the cytokines IL-5, GM-CSF and IL-2, with a concomitant decrease in the production of IFN-γ. The results suggest that passive smoking can induce allergic sensitization to normally harmless antigens and might explain observations indicating that passive smoking is a risk factor for the development of allergy in children. With parental smoking having a prevalence of 40–60%, the results have important implications for public health. J. Immunol. (2001) 167, 4765–4770 LON