Matthew S. Perzanowski

Use of specific IgE in assessing the relevance of fungal and dust mite allergens to atopic dermatitis: A comparison with asthmatic and nonasthmatic control subjects☆☆☆★

BACKGROUND Although allergens have been implicated as aggravating factors in atopic dermatitis (AD), there is little epidemiologic data on the significance of specific IgE. OBJECTIVE We sought to compare sensitization to dust mite and fungi between patients with AD and asthmatic and nonasthmatic control subjects. METHODS Total IgE and specific IgE to Dermatophagoides pteronyssinus, Alternaria alternata, Aspergillus fumigatus, Candida albicans, Malassezia furfur, and Trichophyton rubrum were measured in 73 patients with moderate to severe AD. Total IgE and IgE specific for D pteronyssinus, A alternata, and M furfur were also measured in sera from 156 asthmatic and 212 nonasthmatic control subjects. RESULTS Positive correlations were found between total IgE and IgE antibodies specific for each of the antigens. IgE specific for M furfur was observed more frequently in adults compared with children with AD (P <.01). AD sera had higher levels of total IgE and a higher prevalence of positive sera to D pteronyssinus (95% vs 42% and 17% for subjects with AD, asthmatic subjects, and nonasthmatic subjects, respectively), M furfur (53% vs 1% and 0.5%), and A alternata (49% vs 29% and 18%). Among the sera from subjects allergic to mites, the contribution of IgE specific for D pteronyssinus to the total IgE levels was similar regardless of the clinical status. CONCLUSIONS Our results demonstrate that moderate-to-severe AD is strongly associated with sensitization to dust mite andM furfur (odds ratios, 45.6 and 132 vs pooled control sera). These results suggest that both environmental allergens and colonizing fungi contribute to the severity of disease, which is consistent with the view that mite avoidance and antifungal treatment can be beneficial in the treatment of these patients.

Children living in areas with more street trees have lower prevalence of asthma

Background: The prevalence of childhood asthma in the USA increased by 50% from 1980 to 2000, with especially high prevalence in poor urban communities. Methods: Data on the prevalence of asthma among children aged 4–5 years and on hospitalisations for asthma among children less than 15 years old were available for 42 health service catchment areas within New York City. Street tree counts were provided by the New York City Department of Parks and Recreation. The proximity to pollution sources, sociodemographic characteristics and population density for each area were also measured. Results: Controlling for potential confounders, an increase in tree density of 1 standard deviation (SD, 343 trees/km2) was associated with a lower prevalence of asthma (RR, 0.71 per SD of tree density; 95% CI, 0.64 to 0.79), but not with hospitalisations for asthma (RR, 0.89 per SD of tree density; 95% CI, 0.75 to 1.06). Conclusions: Street trees were associated with a lower prevalence of early childhood asthma. This study does not permit inference that trees are causally related to asthma at the individual level. The PlaNYC sustainability initiative, which includes a commitment to plant one million trees by the year 2017, offers an opportunity for a large prospective evaluation.

Major increase in allergic sensitization in schoolchildren from 1996 to 2006 in northern Sweden

BACKGROUND Time trends for allergic sensitization are poorly known. OBJECTIVE To compare the trends in prevalence of allergic sensitization and associated risk factors in children. METHODS Two cohorts of children (age 7-8 years) were invited for skin prick tests (SPTs) 10 years apart, 1996 and 2006. The participation rates were 2148 (88%) and 1700 (90%), respectively. The methods were identical, and 10 common airborne allergens were used. An expanded International Study of Allergy and Asthma in Children questionnaire about symptoms and possible risk factors for allergic conditions was completed by the parents. RESULTS The prevalence of any positive SPT increased from 21% in 1996 to 30% in 2006 (P < .001). The pattern of sensitization remained similar, and sensitization to cat was most common both years, 13% and 19%, respectively. Sensitization to mites and mold was uncommon in both surveys. A family history of allergy was a significant risk factor for a positive SPT both years (odds ratio, 1.7). Factors that in 1996 had a protective effect, such as rural living and having several siblings, had lost this effect in 2006. The prevalence of most risk factors remained similar, but respiratory infections and smoking among parents decreased significantly. During the same period, there was no significant increase in the prevalence of current wheeze (11.9% to 12.4%, P = .636) or symptoms of rhinitis or eczema. CONCLUSION The prevalence of allergic sensitization increased significantly from 1996 to 2006, whereas no increase in clinical symptoms was found. The parallel decrease in parental smoking and respiratory infections indicate a different influence of environmental factors on allergic sensitization and clinical symptoms, respectively.

Prenatal and postnatal bisphenol A exposure and asthma development among inner-city children

BACKGROUND Bisphenol A (BPA) is used widely to manufacture food container linings. Mouse models suggest exposure to BPA might increase allergic inflammation. OBJECTIVES We hypothesized that BPA exposure, as assessed based on urinary BPA concentrations, would be associated with increased odds of wheeze and asthma and increased fraction of exhaled nitric oxide (Feno) values in children. METHODS The Columbia Center for Childrens Environmental Health recruited pregnant women for a prospective birth cohort study (n = 568). Mothers during the third trimester and children at ages 3, 5, and 7 years provided spot urine samples. Total urinary BPA concentrations were measured by using online solid-phase extraction, high-performance liquid chromatography, isotope-dilution tandem mass spectrometry. Wheeze in the last 12 months was measured by using questionnaires at ages 5, 6, and 7 years. Asthma was determined by a physician once between ages 5 and 12 years. Feno values were measured at ages 7 to 11 years. RESULTS Prenatal urinary BPA concentrations were associated inversely with wheeze at age 5 years (odds ratio [OR], 0.7; 95% CI, 0.5-0.9; P = .02). Urinary BPA concentrations at age 3 years were associated positively with wheeze at ages 5 years (OR, 1.4; 95% CI, 1.1-1.8; P = .02) and 6 years (OR, 1.4; 95% CI, 1.0-1.9; P = .03). BPA concentrations at age 7 years were associated with wheeze at age 7 years (OR, 1.4; 95% CI, 1.0-1.9; P = .04) and Feno values (β = 0.1; 95% CI, 0.02-0.2; P = .02). BPA concentrations at ages 3, 5, and 7 years were associated with asthma (OR, 1.5 [95% CI, 1.1-2.0], P = .005; OR, 1.4 [95% CI, 1.0-1.9], P = .03; and OR, 1.5 [95% CI, 1.0-2.1], P = .04, respectively). CONCLUSIONS This is the first report of an association between postnatal urinary BPA concentrations and asthma in children.

Association of sensitization to Alternaria allergens with asthma among school-age children

BACKGROUND Molds in the Alternaria genus, normally found on outdoor vegetation, produce some of the most common fungal allergens to elicit a skin test response. OBJECTIVES The objectives of this study were to evaluate a serum assay for IgE antibodies to Alternaria allergens and to establish the prevalence of sensitization to Alternaria allergens among children and adults enrolled in epidemiologic studies of asthma. In addition, the significance of sensitization to Alternaria allergens as a risk factor for asthma was compared with that of sensitization to indoor allergens or pollens. METHODS Using the Pharmacia Capsulated Hydrophobic Carrier Polymer (CAP) system, we have evaluated the significance of Alternaria allergens by using sera from several epidemiologic studies of asthma. RESULTS Comparisons between serum assays and skin test results suggest that this in vitro assay yields results similar to those for traditional RASTs and is as sensitive as skin prick testing. In each of the groups studied, sensitization to Alternaria allergens was more common among asthmatic than control subjects, and in two studies the relationship was highly significant. Alternaria allergens were significantly associated with asthma in middle schools in Charlottesville, Virginia and Los Alamos, New Mexico but not in Albemarle County, Virginia. Logistic regression analysis of the results for the three schools identified an association between sensitization to Alternaria allergens and asthma independent of, but not as strong as, that found between sensitization to indoor allergens and asthma (p < 0.001). CONCLUSIONS The Pharmacia CAP system is a useful tool for measuring specific IgE to Alternaria allergens. Although not as important as sensitization to dominant local indoor allergens, sensitization to Alternaria allergens appears to be a significant independent risk factor for asthma in children in some locations of the United States.

Prenatal acetaminophen exposure and risk of wheeze at age 5 years in an urban, low-income cohort

Background Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5 years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway. Methods An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5 years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use. Results 34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5 years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p=0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend <0.001). 68% of children had at least one copy of the GSTP1 minor allele (Val). The risk of wheeze was modified by GSTP1 (additive interaction p=0.009) and was observed only among children with the GSTP1 minor allele. Conclusions Prenatal exposure to acetaminophen predicted wheeze at age 5 years in an inner-city minority cohort. The risk was modified by a functional polymorphism in GSTP1, suggesting a mechanism involving the glutathione pathway.

Evaluation of different techniques for washing cats: quantitation of allergen removed from the cat and the effect on airborne Fel d 1.

BACKGROUND AND OBJECTIVE The purpose of this study was to examine the quantity and distribution of the major cat allergen, Fel d 1, on cats and to evaluate the efficacy of washing, both in removing allergen from the cat and reducing airborne allergen levels. METHODS Airborne samples were collected on four glass fiber filters in a 30 m3 room, before and 3 hours after serial washing of eight cats (45-minute sampling at 18 L/min for each filter). Aliquots of hair and bath water were also collected and assayed for Fel d 1 content. RESULTS Extracting cat hair with tap water or pet shampoo for 3 minutes removed mean levels of 191 and 245 microg of Fel d 1 per gram of hair, respectively; the quantity of allergen on samples of cat hair ranged from 1 microg/gm to more than 1770 microg/gm. The highest concentration of allergen was found on hair from the neck. Estimates of the total Fel d 1 on the cat, based on shaving the whole cat, ranged from 3 to 142 mg (mean = 67 mg). Washing cats reduced airborne allergen 3 hours later. Washing three cats at weekly intervals for 5 weeks in a veterinarians office produced a mean decrease of 44% in airborne Fel d 1 (n = 15, p < 0.02). Washing three cats by immersion for 3 minutes at weekly intervals for a 1-month period produced a mean decrease in airborne allergen of 79% (n = 12, p < 0.001). However, after repeated washing, the airborne levels before the next wash were not consistently decreased. The quantity of Fel d 1 removed by immersion varied from 1 to 35 mg. CONCLUSION Cats carry large quantities of Fel d 1, only a small proportion of which (approximately 0.002%/hr) becomes airborne. Washing cats by immersion will remove significant allergen from the cat and can reduce the quantity of Fel d 1 becoming airborne. However, the decrease is not maintained at 1 week.

Asthma during the primary school ages – prevalence, remission and the impact of allergic sensitization

Background:  Childhood is the most important time for asthma development. The aims of this study were to study changes in prevalence of asthma and wheeze, remission of asthma and changes in risk factor pattern from age 7–8 to age 11–12 in a cohort of school children.

Anti-cockroach and anti-mouse IgE are associated with early wheeze and atopy in an inner-city birth cohort

BACKGROUND The relationships between cockroach and mouse allergen exposure, anti-cockroach and anti-mouse IgE, and wheeze, rhinitis, and atopic dermatitis in children as young as age 3 years are of public health importance but have not been thoroughly evaluated. OBJECTIVE We hypothesized that inner-city children might have anti-cockroach and anti-mouse IgE by age 3 years, and their presence would be associated with respiratory and atopic symptoms. METHODS Children were followed prospectively from birth through age 3 years (n = 404). Residential levels of cockroach and mouse allergens, sera levels of anti-cockroach and anti-mouse IgE, and parental report of wheeze, rhinitis, and atopic dermatitis were measured. RESULTS The odds of early wheeze were significantly higher among children who had IgE to cockroach (odds ratio [OR], 3.3; 95% CI, 1.8-6.2), mouse (OR, 4.6; 95% CI, 2.3-9.0), or both (OR, 9.7; 95% CI, 3.4-27.3). The odds of rhinitis or atopic dermatitis were also higher among children with IgE to cockroach, mouse, or both. Higher IgE class to cockroach and mouse was associated with wheeze and atopic dermatitis (tests for trend, P < .002). CONCLUSIONS Children age 2 to 3 years who have anti-cockroach and anti-mouse IgE are at increased risk of wheeze and atopy. Moreover, a dose-response relationship was found between higher IgE class and increased prevalence of wheeze, rhinitis, or atopic dermatitis. These findings indicate the importance of reducing exposure to cockroach and mouse allergens for susceptible children.

Urban Tree Canopy and Asthma, Wheeze, Rhinitis, and Allergic Sensitization to Tree Pollen in a New York City Birth Cohort

Background: Urban landscape elements, particularly trees, have the potential to affect airflow, air quality, and production of aeroallergens. Several large-scale urban tree planting projects have sought to promote respiratory health, yet evidence linking tree cover to human health is limited. Objectives: We sought to investigate the association of tree canopy cover with subsequent development of childhood asthma, wheeze, rhinitis, and allergic sensitization. Methods: Birth cohort study data were linked to detailed geographic information systems data characterizing 2001 tree canopy coverage based on LiDAR (light detection and ranging) and multispectral imagery within 0.25 km of the prenatal address. A total of 549 Dominican or African-American children born in 1998–2006 had outcome data assessed by validated questionnaire or based on IgE antibody response to specific allergens, including a tree pollen mix. Results: Tree canopy coverage did not significantly predict outcomes at 5 years of age, but was positively associated with asthma and allergic sensitization at 7 years. Adjusted risk ratios (RRs) per standard deviation of tree canopy coverage were 1.17 for asthma (95% CI: 1.02, 1.33), 1.20 for any specific allergic sensitization (95% CI: 1.05, 1.37), and 1.43 for tree pollen allergic sensitization (95% CI: 1.19, 1.72). Conclusions: Results did not support the hypothesized protective association of urban tree canopy coverage with asthma or allergy-related outcomes. Tree canopy cover near the prenatal address was associated with higher prevalence of allergic sensitization to tree pollen. Information was not available on sensitization to specific tree species or individual pollen exposures, and results may not be generalizable to other populations or geographic areas.