OBJECTIVES: The objective of this study was to evaluate the effects of allergen sensitization and family history of atopy on asthma and allergic disease in Chinese schoolchildren from three southeast Asian populations.
METHODS: Written questionnaires on respiratory and allergic symptoms were completed by parents of children of secondary-school age (age range 12 to 18 years) in Hong Kong (n = 1062), Kota Kinabalu in eastern Malaysia (n = 409), and San Bu in southern China (n = 737). A subsample of school-children underwent skin prick testing to common inhalant allergens (Hong Kong 471 children, Kota Kinabalu 321, San Bu 647).
RESULTS: The prevalence of asthma and allergic disease in schoolchildren was highest in Hong Kong, intermediate in Kota Kinabalu, and lowest in San Bu. However, the overall rate of atopic sensitization was similar in the three populations (49% to 63%). House dust mite and cockroach were the two most common allergens causing sensitization and these gave rise to more than 95% of the positive skin test results in all three populations. By regression analysis, mite allergy was associated with rhinitis and asthma in all three populations, and a family history of asthma, rhinitis, or eczema was strongly associated with respective symptoms in the subjects. After adjusting for age, sex, atopic status, and family history of allergic disease, the place of residence remained a significant independent factor for asthma (odds ratio [OR] = 1.0 for Hong Kong, 0.57 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), rhinitis (OR = 1.0 for Hong Kong, 0.59 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), or eczema (OR = 1.0 for Hong Kong, 0.35 for Kota Kinabalu, 1.01 for San Bu, p < 0.001).
CONCLUSION: Sensitization to indoor allergens was a significant risk factor for asthma and allergic disease, and familial clustering of disease was common in the region. However, the marked difference in disease prevalence in the three southeast Asian populations of Chinese schoolchildren cannot be explained by atopic sensitization and family history alone, and the place of residence was an independent risk factor for asthma and allergies, which suggests an important environmental role in disease pathogenesis.
STUDY DESIGN: A non-randomized prospectively collected patients over a three year period, with complaints of nose congestion, rhinorrhea and/or nasal discharge.
RESULTS: There were 435 patients enrolled, 213 children and 222 adults. The children group had a high prevalence of allergen specific IgE to Dermatophagoides pteryonysinus (70%), Dermatophagoides farina (69%), and Blomia tropicalis (55%); followed by dogs (32%), cats (19%) and cockroaches (19%). In the children food allergy category, the top three allergens were egg white (54%), milk (31%) and soya bean (13%). The adult group had results of Dermatophagoides pteryonysinus (71%), Dermatophagoides farina (72%), and Blomia tropicalis (59%); the adult food allergy category, the top 3 allergens were egg white (13%), milk (6%) and soya bean (5%). There was a statistically significant difference in the child and adult group for Dust, D. pteryonysinus, D. farina, B.tropicalis, egg white, wheat, gluten and soya bean. In the age specific child groups, there was an increased in egg food allergy levels, with a peak at the age of five-nine years old and decreasing thereafter (p=0.04). In the children group, the mean Total Nasal Symptom Score (TNSS) was 10.3 (range of 7 to 13); the adult group was similar, with a mean TNSS of 9.8 (range 5 to 12).
CONCLUSION: The prevalence of food allergy in paediatric patients with allergic rhinitis is fairly high and should be considered when treating these children.
METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.
RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.
CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.