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Prevention of new sensitisations in asthmatic children monosensitised to house dust mite by specific immunotherapy. A six-year follow-up study.
G. B. Pajno, G. Barberio et al, Universita di Messina, and ALK-Abello, Milan, Italy
Background: Specific immunotherapy (SIT) is a recognized way of treating IgE-mediated respiratory diseases. The clinical outcome is usually better in allergic children than in adults.
Objective: To increase our knowledge of the ability of SIT to prevent the onset of new sensitisations in monosensitised subjects, so far poorly documented.
Methods: 134 children (age range 5 - 8 years) who had intermittent asthma with or without rhinitis, with only sensitisation to mite allergen (skin prick test and serum specific IgE / RAST), were enrolled. SIT was proposed to all the children's parents, but was accepted by only 75 of them (SIT group). The remaining 63 children were treated with medication only, and were considered the Control Croup. Injection SIT with mite extracts was administered to the SIT group during the first three years and all patients were followed for a total of six years. All patients were checked for allergic sensitisation(s) by skin prick tests and serum-specific IgE (RAST) every year until the end of the follow-up period.
Results: Both groups were comparable in terms of age, sex and disease characteristics. 123 children finished the follow-up study. At the end of the study, 52 out of 69 children (75.4%) in the SIT group showed no new sensitisation, compared to 18 out of 54 children (33.3%) in the control group (p<0.0002). Parieta, Graminea and Olea were the most common allergens responsible for the new sensitisation(s).
Conclusions: According to their data, SIT may prevent the onset of new sensitisations in children with respiratory symptoms monosensitized to house dust mite (HDM). Comments: This is an important study, even though it was not randomised. The researchers believed that a randomised or double-blind placebo-controlled study in which large a number of children are enrolled and treated for several years is neither ethical nor practically feasible.
Role of sulfite additives in wine induced asthma: single dose and cumulative dose studies
H Valley, P J Thompson, Dept of Medicine, The Univ Of Western Australia & Allergy Research Institute Inc, Perth
Background: Wine appears to be a significant trigger for asthma. Although sulfite additives have been implicated as a major cause of wine induced asthma, direct evidence is limited. Two studies were undertaken to assess sulfite reactivity in wine sensitive asthmatics. The first study assessed sensitivity to sulfites in wine using a single dose sulfited wine challenge protocol followed by a double blind placebo controlled challenge. In the second study a cumulative dose sulfited wine challenge protocol was employed to establish if wine sensitive asthmatics as a group have an increased sensitivity to sulfites.
Methods: In study 1, 24 asthmatic patients with a strong history of wine induced asthma were screened. Subjects showing positive response to single blind high sulfite (300 ppm) wine challenge were rechallenged on separate days in a double blind, placebo controlled fashion with wines of varying sulfite levels to characterise their responses to these drinks. In study 2, wine sensitive asthmatic patients (n=12) and control asthmatics (n=6) were challenged cumulatively with wine containing increasing concentrations of sulfite in order to characterise further their sensitivity to sulfite in wine.
Results: 4 of the 24 self-reporting wine sensitive asthmatic patients were found to respond to sulfite additives in wine when challenged in a single dose fashion (study 1). In the double blind dose-response study all four had significant fall in forced expiratory volume in one second (FEV1) > 15% from baseline (i.e. an asthmatic response) following exposure to wine containing 300 ppm sulfite, but did not respond to wines containing 20, 75, or 150 ppm sulfite. Responses were maximal at 5 minutes (mean SD) maximal decline in FEV1 28.7 (13%) and took 15-60 minutes to return to baseline levels. In the cumulative dose-response study (study 2) no significant difference was observed in any of the lung function parameters measured (FEV1, peak expiratory flow (PEF), mid phase forced expiratory flow FEF 25-75) between wine sensitive and normal asthmatic subjects.
Conclusions: Only a small number of wine sensitive asthmatics respond to single dose challenge with sulfited wine under laboratory conditions. This may suggest that the role of sulfites and/or wine in triggering asthmatic responses has been overestimated. Alternatively, cofactors or other components in wine may play an important role in wine induced asthma. Cumulative sulfite dose challenges did not detect an increased sensitivity to sulfite in wine sensitive asthmatics and an alternative approach to identify sulfite/wine sensitive asthma may be required.
Reference: Thorax 2001; 763-769 (October)
Effectiveness of laundry washing agents and conditions in the removal of cat and dust mite allergen from bedding dust
Euan R. Tovey et al Sydney, Australia
Background: There is limited information about the removal of allergens by laundry washing.
Objective: The purpose of this investigation was to determine the dynamics of the removal of mite allergen (Der p 1) and cat allergen (Fel d 1) from bed dust during simulated laundry processes.
Methods: Three studies were performed. The first compared combinations of 4 laundry agents (water alone, soap, detergent with enzymes, and detergent without enzymes), 4 temperatures (12´, 25´, 45´ and 60´ C), and 3 extraction times (5, 20, and 60 minutes). The second study examined allergen extraction by 11 common brands of detergents at 25´ and 45´ C for 5 minutes. The third study compared 4 detergents containing enzymes before and after the denaturation of their enzymes. To measure the quality of allergens extracted, each study used an ELISA assay as well as a more sensitive but semiquantitative Halogen immunoassay to detect any allergens remaining after the simulated laundry extraction.
Results: Study 1 showed that detergents extracted more of both Fel d 1 and Der p 1 than either soap or water alone and that almost all allergens were extracted within 5 minutes at 25´. However, washing at 60´ C extracted slightly more Fel d 1 and denatured Der p 1, resulting in lower residual amounts of both allergens. Study 2 showed that all the commercial detergents performed similarly. Study 3 showed that the presence of enzymes in detergent formulations did not produce a significant effect on the extraction of allergens.
Conclusions: Using detergent solutions at 25´ for at least 5 minutes was sufficient to extract most mite and cat allergen from dust of bedding.
Reference: J Allergy Clin Immunol 2001; 108: 369 ? 374
Local side-effects of inhaled steroids in asthmatic children
Background: The objective was to investigate the local side-effects of inhaled steroids (ICS) in daily life in asthmatic children, particularly the younger ones, by observational prospective cross-sectional cohort study.
Methods: Asthmatic children (n=639, 75.9+/-48.9 months, 61.3% boys), treated with beclomethasone dipropionate (BDP) (721.0+/-287.3µg per day) or budesonide (BUD) (835.5+/-684.9µg per day) for at least 1 month, were recruited at the time of a scheduled visit. Local side-effects were researched by a questionnaire (cough during inhalation, hoarseness, dysphonia, and thirsty feeling) and clinical examination (peri-oral dermatitis, oral candidiasis, and tongue hypertrophy).
Results: Exactly 63.3% of the children under 6 years of age and 59.5% of the older ones reported one local side-effect. Cough (39.7%) was dependent on young age, use of BDP, and mainly use of spacer device, with an OR of 4.7 (95% CI: 2.7-8.2). Thirsty feeling (21.9%) and hoarseness (14.1%) occurred in children using ICS and long-acting â2- agonist. Dysphonia (11.1%) was favoured by high doses of BDP and BUD, and by inhalation from spacer devices or nebulizers. No factor favoured oral candidiasis (10.7%). Peri-oral dermatitis (2.9%) and tongue hypertrophy (0.1%) were associated with nebulization.
Conclusions: Local side-effects of ICS are common in asthmatic children of all ages, and the device used constitutes the most influential factor.
Reference: Allergy 2001: 56: 944-948
Pet allergen levels in homes in Ghana and the UK
Ashley Woodcock et al Manchester, UK, and Kumasi, Ghana
Background: Recent studies highlight the importance of sensitisation to cat and dog allergens in asthma in developed countries with high rate of pet ownership. The situation in developed countries is markedly different. It has been reported that the prevalence of exercise-induced bronchospasm and atopy was twice as common in rich urban population in Ghana than in children from poor urban and rural communities, with a strikingly low prevalence of allergies to cat and dog (both <1%) despite apparently high pet ownership.
Aim of the study: was to measure the levels of major cat and dog allergens in homes with pets and homes without pets in a developing country (Ghana) and compare them with the levels in a developed country (the UK)
Methods: The study was carried out in Kumasi, Ghana (estimated population, ~1million) and Manchester, UK. Levels of Cannis familiaris group 1 allergen (Can f 1) and Felis domesticus group 1 allergen (Fel d 1) in 100 Ghanian homes (49 without pets, 16 with cats only, 15 with dogs only, and 20 with dogs and cats) were compared with those in 410 homes in the UK (258 without pets, 75 with cats only, 64 with dogs only, and 13 with cats and dogs). Dust collection was done over 1-m2 area of bedding for 2 minutes through use of a vacuum cleaner. Can f 1 and Fel d 1 were assayed in the same lab (UK) at the same time.
Results: In the UK , homes with pets contained much higher allergen levels than did homes with pets in Ghana ( for Fel d1 : mean difference, 275-fold; CI, 129-fold to 594-fold; P<.0001; for Can f 1: mean difference, 75-fold, 95%CI, 33-fold to 169-fold; P<.0001). In the UK homes without cats contained significantly higher levels of cat allergen than did homes with cats in Ghana (mean difference, 3.7-fold; 95% CI, 2.0-fold to 7.2-fold; P< .0001).
For the dog allergen can f 1, there was no difference between homes without dogs in the UK and homes with dogs in Ghana. Difference in allergen levels between homes with pets and homes without pets were much greater in the UK than in Ghana.
Conclusion: Levels of pet allergens in Ghanian homes with pets were between 75-fold (dog) and 275-fold (cat) lower than levels in homes with pets in the UK and lower than or comparable to levels in homes without pets in the UK.
Reference: J Allergy Clin Immunol 2001; 108: 463-465
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