Asthma in Children: Effects of Exposure to Diesel Exhaust Particles
By The Editors
Diesel exhaust particles are one of the major components of air pollution. These particles are suspended in the air, and are microscopic — less than one-fifth the thickness of a human hair. As we breathe, they are drawn deep into the lungs. Because diesel-powered engines are everywhere, it is almost impossible to avoid them. People that live and work in urban and industrial areas are more likely to be exposed. Combined results from many epidemiological, clinical, and toxicological studies show that diesel exhaust particles are associated with respiratory disorders, as for example severe asthma.
It is not surprising that children are especially susceptible to the effects of these particles. Results form a recenty study entitled “Diesel exhaust particle induction of IL-17A contributes to severe asthma” and published onine (September 23, 2013) in the Journal of Allergy and Clinical Immunology, show that exposure to diesel exhaust particles from traffic pollution leads to increased asthma severity in children.
The study was conducted by researchers at Cincinnati Children’s Hospital Medical Center. and provides insight into the mechanisms responsible for the development of severe asthma in children exposed to high levels of diesel exhaust particles — these mechanisms involve expansion of a type of white blood cells called T helper 17 cells and increased production by these cells of a protein, IL-17A. This protein is known to be associated with several chronic inflammatory diseases, including rheumatoid arthritis, psoriasis and multiple sclerosis.
The researchers studied 235 children and teens with asthma by estimating their diesel exposure attributable to traffic based on where they lived. The researchers also studied mice exposed to diesel particles and dust mites, a common household allergen.
In children with asthma, diesel exposure was associated with more frequent asthma symptoms and increased IL-17A blood levels. In mice, exposure to diesel and dust mites resulted in more severe asthma when compared to dust mite exposure alone. Neutralization of IL-17A in mice resulted in alleviation of airway inflammation induced by diesel exposure.
Gurjit Khurana Hershey, MD, PhD, director of asthma research at Cincinnati Children’s and senior author of the study says that neutralization of IL-17A “may be a useful potential therapeutic strategy to counteract the asthma-promoting effects of traffic-related air pollution, especially in highly exposed, severe allergic asthmatics.”
I just read another article where the EPA is starting to fine companies and individuals for diesel idling. In one circumstance, they had fined school buses for idling in school zones, where kids were present. So, it looks like they are finally taking it serious and starting to do something about our children inhaling all of these harmful fumes from diesels.
The interleukin 17 family has also been linked to various common immune malfunctions other than asthma (rheumatoid arthritis, lupus, Psoriasis), so I am curious to know diesel exposure’s effects on on these fairly common ailments as well. It stands to reason that such illnesses would also be amplified by inhalation of diesel particulates. I, too, am concerned that am IL 17 suppressive treatment would leave a significant gap in immune function. However, a 2012 clinical trial showed positive results in a anti-IL 17 antibody trial (http://www.nature.com/nbt/journal/v30/n6/full/nbt0612-475.html), so perhaps there is a viable solution there.
The only viable solution is to reduce diesel emissions, why treat the symptoms while leaving the cause unchanged?
I know that any type of exhaust is detrimental, but I think it would have been interesting if different types of diesel was used to see if there was a change in the induction of IL-17A. Since there is an effort to be more environmentally friendly (using biodiesel & synthetic diesel), I wonder if anyone has looked into effects that these new types of diesel would have. I think it would be nice to develop a way to neutralize these interleukins, but I’m just concerned about the protective function being lost in a treatment.