Mite allergen (Der p 1) on children’s clothing

Abstract

Tovey et al. (J Allergy Clin Immunol 1995;96:999-1001) present some interesting data regarding Der p 1 levels on adults’ clothing. We report here results of a study of Der p 1 levels on children’s clothing. Dust was collected by a standardized method with a portable vacuum cleaner for 3 minutes from both sides of upper garments (sweatshirts, polar fleece tops, knitted jerseys, and long-sleeved shirts) of 166 school-children (75 male, 91 female) aged 7 to 9 years from primary schools in Wellington, New Zealand, during July 1995 (winter). Each garment’s fabric type was recorded. All collected dust was sieved through a 425 μm pore filter and extracted in phosphate-buffered saline before analysis for Der p 1 by a double monoclonal antibody ELISA method.1Luczynska CL Arruda LK Platts-Mills TAE Miller JD Lopez M Chapman MD. A two-site monoclonal antibody ELISA for the quantification of the major Dermatophagoides spp. allergens, Der p 1 and Der f 1.J Immunol Methods. 1989; 118: 227-235Crossref PubMed Scopus (392) Google Scholar Statistical analysis was carried out by analysis of variance on log-transformed Der p 1 data. The geometric mean (95% confidence interval) for Der p 1 was 2.77 μg/gm (2.43, 3.23), and mean dust weight collected was 0.060 gm (0.054, 0.065). Only nine of the 166 garments contained more than 10 μg/gm of allergen, 96 garments contained 2 to 10 μg/gm, and 61 garments contained less than 2 μg/gm. Geometric mean Der p 1 was 3.60 μg/gm (3.04, 4.25) on girls’ garments compared with 2.02 μg/gm (1.66, 2.46) on boys’ garments (p < 0.0001), with no significant difference in weights of dust collected (mean, 0.056 gm vs 0.064 gm; p = 0.17). Table I shows Der p 1 results in micrograms per gram of fine dust and micrograms of total allergen recovered in the 3-minute sampling period according to the fabric type.Tabled 1Der P 1 levels on garments according to fabric type. Results are means (dust weight) or geometric means (Der P 1) with 95% confidence intervals in parenthesesDer P 1Fabric TypenDust Weight (gm)μg/gmTotal μgCotton400.025* (0.019-0.030)3.60 (2.74-4.73)0.069† (0.049-0.097)Polyester/cotton600.061† (0.052-0.070)2.09‡ (1.67-2.62)0.105† 0.079-0.139)Polyester470.080 0.071-0.090)2.62§ (2.08-3.30)0.184 (0.137-0.249)Wool190.078 (0.063-0.092)4.51 (3.05-6.66)0.296 (0.172-0.508)p <0.05 compared with *polyester/cotton, †polyester and wool, ‡cotton and wool, § wool. Consfidence intervals are given in parentheses. Open table in a new tab Results from this study indicate that the type of fabric influences the amount of allergen on garments. We cannot exclude the possibility that woolen garments contain higher levels of Der p 1 because they are washed less frequently, but we did not ascertain when garments were last washed. The difference in Der p 1 could also be due to differences in electrostatic charges retaining allergen or differences in mite infestation of different fabric types. More puzzling is why girls’ clothing contains higher levels of Der p 1. There was no significant difference in the type of garment worn between girls and boys (p = 0.66), and the difference between boys and girls remained significant when fabric type was incorporated into a two-factor analysis of variance (p = 0.0007). It is possible that the girls’ garments were washed less frequently. It could also be that girls spend more time in direct contact with carpets, furniture, and bedding, which are the main sources of mites and allergens. We concur with Tovey et al. that clothing is an underrecognized source of house dust mite allergen exposure. Levels of Der p 1 found in our study are, however, considerably lower than those found in their study, even though Wellington bedding and floor allergen levels are similar to those in Sydney.3 The subjects the study by Tovey et al. were adults, there were some differences in the types of garments worn, and it seems likely that children’s clothing would be washed more frequently than the adults’ clothing. Patients allergic to house dust mite allergens should perhaps avoid woolen garments to further minimize their exposure to Der p 1. This study was supported by the Health Research Council of New Zealand. 1/8/75060