| Allergic diseases are influenced by both environmental and genetic factors. The aim of this study was to investigate the effects of environmental exposure and susceptibility genes on the manifestation of asthma in Hong Kong.; For studying environmental exposure, house dust was collected from the bed, bedroom, lounge and kitchen floors of 211 asthmatic patients and 90 age- and sex-matched non-allergic control subjects. Concentrations of house dust mite, cockroach and cat allergens (Der p 1, Bla g 2 and Fel d 1 respectively) were assayed by enzyme-linked immunosorbent assay. It was found that asthmatic patients had a significantly higher serum total IgE level than control subjects (mean IgElog: 2.332 vs 1.780; p < 0.0001). Results demonstrated that the incidence of asthma in Hong Kong does not have a simple correlation with environmental exposure.; For assessment of genetic predisposition, the association between Chinese asthmatic children and 12 candidate asthma-associated polymorphic markers was investigated using restriction fragment length polymorphism. Seventy-six asthmatic patients (M:51, F:25; mean age 10.6 years, range 2--20), and 70 age- and sex matched non-allergic control subjects were recruited.; Our genotyping results showed the allelic frequencies of 150V of IL-4 receptor and the 2 polymorphisms of beta2-adrenoceptor, in the Chinese population was similar to other Asian populations but different with the Caucasians. Consistent with other published reports, the R275Q substitution in the CC chemokine receptor 3 was only rarely found in the Chinese population. There was also a significant association between R130Q polymorphism of IL-13 and serum total IgE (p = 0.005) and specific IgE to Der p 1 (p = 0.021), mixed cockroaches (p = 0.03), and dog (p = 0.003). Patients heterozygous for IL1B3954 polymorphism had higher serum total IgE concentration (P = 0.034) and RAST class to Der p 1 (P = 0.054) than the homozygous wild-type. Polymorphism in IL1RN significantly correlated with RAST class to cat (P = 0.015) and molds (P = 0.003).; The results of this study have shown possible links between asthma in Hong Kong and the following two factors: (1) level of Der p 1 exposure in mite sensitized patients, and (2) ethnic differences in the allelic frequencies of some candidate atopy susceptibility genes and in their association with asthma have been demonstrated. (Abstract shortened by UMI.)... |
