Browsing by Author "Douglass, J."

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    Association between serum total IgE, allergic diseases and geohelminth infections in Sri Lankan children
    (BioMed Central, 2007) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Douglass, J.; O’Hehir, R.E.; Weerasinghe, A.
    BACKGROUND: Elevated levels of total IgE (tIgE) in serum are characteristic of allergic diseases. Levels of tIgE are influenced by genetic predisposition, age, sex and helminth infections. However, the association between tIgE and allergic diseases in children living in areas endemic for helminth infections is not clear. The aim of our study was to assess the relationship between tIgE, allergic diseases and geohelminth infections in children. METHODS: A total of 640 schoolchildren 9Y11 years of age was selected by stratified random sampling. Data regarding allergic diseases (asthma, rhinitis and eczema) were collected by a standard questionnaire given to the parent or guardian. Screening for helminth infections was done by examining their fresh stool samples by modified Kato-Katz technique. Serum tIgE was measured by Fluoroenzymeimmunoassay in 67 geohelminth-positive subjects and in a comparable group of geohelminth-negative subjects. RESULTS: The mean age in the study population was 10 years (SDT0.3). The prevalence of geohelminth infection was 15.5%. Trichuris trichiura (14.3%) was the most common followed by Ascaris lumbricoides (4.2%) and hookworm (0.2%). Mixed infection was detected in 20.3% of infected children. Infection intensity was light in 68.9% of infected children while 28.4% and 2.7% showed moderate and heavy infection respectively. The cumulative prevalence of allergic diseases was 33.7%. Prevalence of asthma, rhinitis and eczema was 17%, 21.4% and 5% respectively. Serum tIgE concentrations showed a positively skewed distribution. Geometric mean (GM) for tIgE for the geohelminth infected group (1039.9kU/L) was significantly higher than that of the non-infected group (575.4kU/L) (p = 0.004). It was also higher in the allergic group (933.3kU/L) than in the non-allergic group (639.7kU/L) but the difference was not statistically significant (p = 0.068). The GM for tIgE for non-allergic children in the study population was much higher than that seen in non-allergic children in developed countries. CONCLUSION: Serum tIgE concentration was strongly associated with the presence of geohelminth infections in children. Serum tIgE may not be a useful marker for allergic diseases in children living in areas endemic for geohelminth infections. © 2007 World Allergy Organization
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    Reduced risk of atopic diseases among schoolchildren infected with intestinal Nematodes
    (Federation of Immunology Societies of Asia-Oceania, 2008) Amarasekera, N.D.D.M.; Gunawardena, N.K.; de Silva, N.R.; Pathmeswaran, A.; Douglass, J.; O’Hehir, R.; Weerasinghe, A.
    BACKGROUND: The effect of helminth infections on atopic diseases and allergic sensitization is controversial. Little is known about the effect of infection on atopic diseases in children living in areas where both intestinal nematodes and Toxocara infections are prevalent. OBJECTIVE : To examine the association between atopic diseases and helminth infection among children exposed to both intestinal nematodes and Toxocara. METHODS: Children attending grade 5 (age group 9-11 years) in 17 schools in the Western Province of Sri Lanka were recruited. The association of atopic diseases (asthma, rhinitis, eczema) with active intestinal nematode infections (excreting eggs in faeces) and with exposure to Toxocara (specific IgG antibodies in serum) was investigate. A child was deemed sensitized if positive for at least one of the allergens tested (Dermatophagoides pteronyssinus, Blomia tropicalis, cockroach, cat epithelium, grass pollen), based on specific IgE levels in serum. RESULTS : A total of 640 children participated in the study; serum analysis was done in 203. Active intestinal nematode infection appeared to reduce the risk of atopic diseases (OR 0.47, P=0.0I6) whereas Toxocara exposure did not (OR 0.85, P=0.602). When specific IgE levels against Blomia tropicalis, the most common allergen in the study group (67.5%), were expressed as percentages of the total IgE levels for each child, infected children had significantly lower levels compared to uninfected children (P=0.001). CONCLUSIONS : Intestinal nematode infections seem to protect against atopic diseases in children in the tropics. Polyclonal IgE synthesis may be involved in this protection.
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    Rhinitis and asthma: it's one airway after all
    (Medicine Today Pty Limited, 2006) Amarasiri, D.L.; Douglass, J.
    The concept of `united airways disease - that allergic asthma and rhinitis are manifestations of a single inflammatory airways disease - is supported by laboratory and epidemiological studies and by treatment responses