6. Air pollution and the respiratory allergic response
In a recent study in the USA, researchers challenged allergic rhinitis patients with known sensitivity to ragweed by exposing them to the allergen with or without diesel exhaust particles (DEPs). These DEPs apparently represent 40% of the smaller pollutants in cities such as Los Angeles. The combination of allergen plus DEPs aggravated the allergic response in individuals with null expression of one of the glutathione S-transferase enzymes (GSTM1-null). This finding confirmed earlier work which proposed that air pollutants such as DEPs produced their pulmonary effects and damage as a result of oxidant stress. Ambient particles carry redox-active metals and quinones deep into the respiratory tree where they may evade and overcome the lung's antioxidant defences. Subjects who are frankly deficient in one or more of the important glutathione S-transferase superfamily of antioxidants will clearly be at a disadvantage and experience more severe disease. The converse was also shown i.e. individuals who carried the genotypes that most efficiently metabolized reactive oxygen species had lower IgE and histamine responses to allergen plus DEPs. These results might be particularly relevant at a time when fuel efficiency is high on the agenda of motor manufacturers, and low-consumption diesel engines are enjoying unprecedented popularity in the US, Europe and Australasia.
Read more:
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