Clinical study of the relationship between organophosphate insecticides exposure and allergic asthma in preschool children

ABSTRACT

Bronchial asthma is a major public health problem affecting millions of people worldwide. There is an increasing concern that the prevalence of the disease could be attributed to new or modified patterns of exposures to chemicals, including insecticides. Organophosphates insecticides [OPs] account for 50% of all insecticides used. Chlorpyrifos is the third most commonly used among all pesticides applied by homeowners and commercial applicators. Interlukin-4 [IL-4] is one of the most important cytokines underlying the development of the allergic asthma. The aim of this work was to evaluate the relationship between the immunomodulatory effects of the environmental exposure to organophosphate insecticides and allergic asthma in preschool children living in rural areas. The current study was conducted in the period from October, 2008 to October 2010. 200 children were classified into 2 groups Group I 100 diseased preschool children, living in rural areas and diagnosed as allergic asthma, selected from the pediatrics outpatient clinic, Zagazig University Hospitals. Group II Control group, 100 healthy children matching the diseased group in the age, sex and residency, selected from the outpatient clinic of minor surgeries, Zagazig University Hospitals. There was a non-significant difference between males and females or between different age categories of the asthmatic group as regard severity of asthma. Serum interleukin-4 and concentration were significantly higher in the asthmatic group as compared to the control group. A significant positive correlation was found between either IL-4 level and clorpyriphos concentration and the severity of asthma. Moreover, there was a significant positive correlation between chlorpyrifos concentration and IL-4 level in the asthmatic children. It was concluded that exposure to organophosphate insecticides [OPs] is associated with elevated serum IL-4 which plays important role in the pathogenesis of allergic asthma. This immunomodulating effect of OPs can explain the increased prevalence of allergic asthma among rural preschool children exposed to these insecticides