Indoor allergen exposure in primary school classrooms in New Zealand.

AIM: Indoor allergens exposure is a risk factor for respiratory symptoms in sensitised children. There is limited data on indoor allergen exposures in New Zealand schools. METHODS: Vacuumed floor dust samples were collected from 136 classrooms in 12 primary schools and analysed for allergens from the house dust mite Dermatophagoides pteronyssinus (Der p 1), cat dander (Fel d 1), cockroach (Bla g 2), cow dander (Bos d 2), horse dander (Equ c 4) and peanut (Ara h 2) by ELISA. RESULTS: House dust mite, cat, cockroach, cow and horse allergens were detected in 96.4%, 100%, 2.2%, 27.0% and 59.9% respectively in the classrooms dust samples. Thirty-one (22.6%) classrooms had Fel d 1 levels of >8.0µg/g while none had Der p 1 levels of >10.0µg/g. Only one classroom had detectable levels of peanut allergen. CONCLUSIONS: House dust mite allergen levels were low in New Zealand classrooms while about a quarter of classrooms had cat allergen levels that may be associated with respiratory symptoms.

Serum periostin in obstructive airways disease.

Serum periostin is a potential biomarker of response to therapies that target type 2 inflammation in asthma. The objectives of this study were to describe: 1) the distribution of serum periostin levels in adults with symptomatic airflow obstruction; 2) its relationship with other variables, including type 2 biomarkers; and 3) the effect of inhaled corticosteroids on periostin levels.Serum periostin levels were measured in a cross-sectional study exploring phenotypes and biomarkers in 386 patients aged 18-75 years who reported wheeze and breathlessness in the past 12 months. In 49 ICS-naïve patients, periostin levels were measured again after 12 weeks of budesonide (800 µg·day(-1)).The distribution of serum periostin levels was right skewed (mean±sd 57.3±18.6 ng·mL(-1), median (interquartile range) 54.0 (45.1-65.6) ng·mL(-1), range 15.0-164.7 ng·mL(-1)). Periostin was positively associated with exhaled nitric oxide (Spearman's rho=0.22, p<0.001), blood eosinophil count (Spearman's rho=0.21, p<0.001), and total IgE (Spearman's rho=0.14, p=0.007). The Hodges-Lehmann estimator (95% CI) of change in periostin level after ICS therapy was -4.8 (-6.7- -3.2) ng·mL(-1) (p<0.001).These findings provide data on the distribution of serum periostin in adults with symptomatic airflow obstruction, the weak associations between periostin and other type 2 markers, and the reduction in periostin with inhaled corticosteroid therapy.

Cat, dog and house dust mite allergen levels on children's soft toys.

OBJECTIVE: Children's soft toys are known to harbour house dust mite (HDM) allergens, but little is known whether they harbour cat or dog allergens. The objective of the study was to measure cat (Fel d 1), dog (Can f 1) and HDM allergens on children's soft toys. METHODS: Dust was collected from 40 children's soft toys and their mattresses. Data were collected on pet ownership. Dust samples were analysed for Fel d 1, Can f 1, Der p 1 and Der f 1 by enzyme-linked immunosorbent assay (ELISA) and results are expressed as median levels with inter-quartile ranges. RESULTS: Thirty-five (87.5%) soft toys had detectable Fel d 1 levels (median: 0.73 µg/g; inter-quartile range: 0.26-2.56 µg/g) while 34 (85%) had detectable Can f 1 levels (1.20 µg/g; 0.53-2.68). Correspondingly, 32 (80%) mattresses had detectable Fel d 1 levels (0.18 µg/g, 0.07-1.01) while 34 (85%) had detectable Can f 1 levels (0.50 µg/g; 0.33-1.06). All mattresses and soft toys had detectable HDM allergen (Der p 1 + Der f 1) levels with soft toys containing about three times higher levels than mattresses. In homes with cats (n = 10) Fel d 1 levels were higher on soft toys than homes without cats (2.49 versus 0.48 µg/g; p = 0.0009). In homes with dogs (n = 25) Can f 1 levels were generally higher on soft toys (1.38 versus 0.63 µg/g; p = 0.10). CONCLUSIONS: This study has shown that soft toys can harbour cat and dog allergen as well as HDM allergens, some with very high levels. Cat and dog ownership resulted in higher Fel d 1 and Can f 1 levels on soft toys and mattresses. The levels of Fel d 1, Can f 1 and HDM allergens on soft toys could be of importance to sensitized asthmatic children.

Measurement of ß-(1,3)-glucan in household dust samples using Limulus amebocyte assay and enzyme immunoassays: an inter-laboratory comparison.

Environmental levels of ß-(1,3)-glucan, an inflammatory fungal cell wall component, have been suggested to be related to respiratory symptoms. However there is currently little data comparing ß-(1,3)-glucan detection methods and/or results obtained in different laboratories. The aim of this study was to compare levels of ß-(1,3)-glucans detected in household dust samples (n = 40) using different extraction/detection methods (Limulus amebocyte assay (LAL), inhibition enzyme immunoassay (EIA) and sandwich EIA) in five different laboratories. Dust sample aliquots were sent to participating centres, extracted and analysed for ß-(1,3)-glucan according to standard in-house procedures. Significant differences in the levels of ß-(1,3)-glucan were observed between all laboratories (geometric mean levels ranging from 15.4 µg g (-1) to 4754 µg g(-1) dust; p < 0.0001) with the exception of those using a similar LAL method. The inhibition EIA used in laboratory D produced mean ß-(1,3)-glucan measurements 80-100 times higher than the LAL assays, 4 times higher than the sandwich EIA in the same lab, 17.6 times those obtained with the EIA in lab E and 363 times those obtained in the EIA in laboratory C. Pearson's correlations generally showed significant associations between methods and laboratories, particularly those using similar methodology (R ranging from 0.5 to 0.8; p < 0.001), although some poor and even inverse correlations were observed. Bland-Altman analyses showed moderate to good agreement between most assays, although clear absolute differences were observed. In conclusion, although results obtained with different methods were often significantly correlated and therefore comparable in relative terms, direct comparison of results between laboratories and assays may be inappropriate.

Effect of freezing, hot tumble drying and washing with eucalyptus oil on house dust mites in soft toys.

Soft toys are a major source of house dust mites (HDM) and HDM allergens, and sleeping with soft toys is a significant risk factor for HDM sensitization. We studied three techniques to eliminate HDM from soft toys, namely freezing, hot tumble drying and washing with eucalyptus oil. Thirty-six toys (12 in each treatment group) were enumerated for live HDM by the heat escape method before and after freezing overnight, hot tumble drying for 1 h and washing in 0.2% to 0.4% eucalyptus oil. Freezing, hot tumble drying and washing with eucalyptus oil resulted in significant reductions in live HDM, an average reduction of 95.1%, 89.1% and 95.1%, respectively. Additionally, washing with eucalyptus oil resulted in a significant reduction in HDM allergens as well from a geometric mean of 9.12 µg/g to 0.37 µg/g (p = 0.033). These three HDM elimination techniques give parents of infants effective and acceptable methods of limiting HDM exposure.

Endotoxin and ß-(1,3)-glucan levels in automobiles: a pilot study.

Exposure to bacterial endotoxin and fungal ß-(1,3)-glucan in the indoor environment can induce respiratory symptoms. Automobiles are an exposure source of allergens but it is not known if, and how much exposure there is to endotoxin and fungal ß-(1,3)-glucan. The objective of the study was to determine whether automobiles are a potential source of exposure to these microbial products. Dust was sampled from the passenger seats of 40 automobiles. Specific Limulus amoebocyte kinetic assays were used to measure endotoxin and ß-(1,3)-glucan, respectively. Endotoxin and ß-(1,3)-glucan was detected in all samples ranging from 19.9-247.0 EU/mg and 1.6-59.8 µg/g, respectively. There were no significant differences in endotoxin levels between automobiles of smokers and non-smokers, but ß-(1,3)-glucan levels were about two-fold higher in the automobiles of non-smokers. In conclusion, endotoxin and ß-(1,3)-glucan exposure in automobiles at levels found in our study may be of importance for asthmatics.

Endotoxin and indoor allergen levels in kindergartens and daycare centres in Wellington, New Zealand.

AIMS: A large majority of children in New Zealand attend daycare centres and kindergartens early in life. Overseas studies have demonstrated a possible protective effect of daycare attendance against asthma and allergy later in life. One hypothesised agent for this protection is high levels of endotoxin, which have not previously been measured in New Zealand childcare facilities. The purpose of this study was to measure endotoxin and indoor allergens in kindergartens and daycare centres in the Wellington region. METHODS: Dust samples were collected from 18 kindergartens and 18 daycare centres and analysed for endotoxin by the kinetic limulus amebocyte lysate assay and for indoor allergens by double monoclonal/polyclonal antibody ELISA. RESULTS: The geometric mean level (95% CI) was 29,206 EU/g (19,410-43,950) for endotoxin, 0.25 mcg/g (0.04-2.28) for Der p 1, 1.24 mcg/g (0.80-1.90) for Fel d 1, 0.43 mcg/g (0.26-0.71) for Can f 1, and 0.028 mcg/g (0.020-0.039) for Bla g 2. CONCLUSIONS: Endotoxin levels in daycare centres and kindergartens in Wellington, New Zealand are similar to domestic dwellings in Wellington, however indoor allergen levels are much lower. The low indoor allergens in the daycare centres and kindergartens are unlikely to be problematic for sensitised infants, although some individual childcare facilities had very high Der p 1 levels.

Endotoxin exposure, wheezing, and rash in infancy in a New Zealand birth cohort.

BACKGROUND: Wheezing in infancy is common and is associated with small lungs, viral respiratory tract infection, and environmental tobacco smoke exposure. Recently, increased levels of endotoxin in the domestic environment have also been associated with infant wheezing, particularly among infants with a family history of atopic disease. OBJECTIVE: To explore associations between exposure to endotoxin at 3 months of age and reported symptoms of wheezing, rhinitis, itchy scaly rash, and atopy at 15 months in a birth cohort of 881 New Zealand children. METHODS: Using standardized methods, a 1-m(2) site from the bedroom floors of the 3-month-old infants was sampled and analyzed for endotoxin. RESULTS: Wheezing was significantly associated with higher endotoxin levels (odds ratio [OR], 1.54; 95% CI, 1.03-2.30), particularly among infants with a parental history of allergic disease (OR, 1.67; 95% CI, 1.07-2.60). Higher endotoxin concentrations were also strongly associated with recurrent itchy rashes (OR, 1.87; 95% CI, 1.14-3.05), particularly among infants who were atopic (OR, 4.64; 95% CI, 1.56-13.77) or had a parental history of allergic disease (OR, 2.10; 95% CI, 1.22-3.61). CONCLUSION: Domestic endotoxin was associated with reported airway and skin symptoms in this large group of New Zealand infants. The role of endotoxin in the development of respiratory and skin disease in infancy deserves further study. CLINICAL IMPLICATIONS: Reducing domestic endotoxin exposure might reduce infant wheezing and atopic dermatitis, but the long-term benefits of this remain unclear.

Endotoxin, (1 --> 3)-beta-D-glucans and fungal extra-cellular polysaccharides in New Zealand homes: a pilot study.

Bacterial endotoxin, fungal (1 --> 3)-beta-D-glucans, and extracellular polysaccharides from Aspergillus and Penicillium (EPS-Asp/Pen) have been suggested to be stable markers of microbial exposure. This paper describes a pilot study in which we measured endotoxin, (1 --> 3)-beta-D-glucans, EPS-Asp/Pen and mite allergen in house dust collected in 32 homes in Wellington, New Zealand. Endotoxin (GM 60,295 EU/g; GSD 2.4) and glucan (GM 2,687 microg/g; GSD 1.5) levels were higher in comparison to previous international studies, whereas EPS-Asp/Pen levels (37,347 Units/g; GSD 1.9) appeared comparable. Concentrations expressed per square meter were highly correlated among the measured components (p < 0.05). When expressed per gram of dust only (1 --> 3)- beta -D-glucans and EPS-Asp/Pen were correlated (r=0.55, p < 0.01; n=32). Endotoxin and glucan levels were higher (borderline statistically significant; p < 0.10) in homes with self-reported water damage. A positive association (p < 0.10) was also found for dust mite and a combination of self-reported mould, dampness and water damage. EPS levels were higher in homes where residents indicated the presence of mould spots on the wall, but this did not reach statistical significance. In conclusion, levels of microbial contaminants in a small random sample of New Zealand homes were high and weakly associated with water damage.

Endotoxin and house dust mite allergen levels on synthetic and buckwheat pillows.

Pillows are known to contain significant levels of indoor allergens and endotoxin, that are of importance to house dust mite sensitized asthmatics. Buckwheat pillows are commonly used in Korea. We studied the levels of the house dust mite allergen, Der f 1, and endotoxin on new synthetic and buckwheat pillows and their accumulation over three months. Endotoxin levels were significantly higher on new buckwheat pillows compared to synthetic pillows; geometric mean levels (95% CI) were 60,950 EU/g (30,270-122,700) and 4,887 EU/g (2,570-9,311) respectively (p<0.001). No Der f 1 was detected on the new pillows. After three months Der f 1 levels were similar on buckwheat and synthetic pillows, geometric mean levels (95% CI) were 1.16 microg/g (0.02-8.13) and 1.08 microg/g (0.19-1.68) respectively. These results indicate that buckwheat pillows are a source of very high endotoxin levels that may be of relevance to asthma severity of atopic asthmatics.

The determinants of dust mite allergen and its relationship to the prevalence of symptoms of asthma in the Asia-Pacific region.

The role that house dust mites play in the primary causation of asthma is controversial. Approximately thirty-six 10-yr-old children in each of 10 centres in the Asia-Pacific region participated. Researchers collected dust from mattresses and living room floors using standardized procedures. Der p1 and Der f1 were analysed using a double monoclonal antibody enzyme-linked immunosorbent assay. Geometric mean allergen levels were calculated for each centre. An ecological analysis was conducted to show the regression of the geometric mean allergen level, using the highest household level, against asthma symptom and severity prevalence data from the International Study of Asthma and Allergies in Childhood, Phase I. Among children aged 13-14 yr, the change in asthma symptom prevalence was associated with per unit change in Der p1 microg/g (1.08, 95% CI 0.10-2.06) and Der 1 microg/g (Der p1 + Der f1) (0.64, 95% CI 0.02-1.26). The change in having four or more attacks of asthma in the last 12 months was associated with per unit change in Der p 1 microg/g (0.29, 95% CI -0.02 to 0.60) and Der 1 microg/g (0.20, 95% CI 0.01-0.38). There was no effect for total Der p1 or Der f1 (total or microg/g). Among children aged 6-7 yr, neither allergen was related to symptoms or severity prevalence. While our findings suggest that Dermatophagoides pteronyssinus may have a role in the primary causation of asthma, the complexity of this association reinforces the need for prospective studies.