Allergen Levels in Airborne and Surface Dust

House dust mite Der p I Der p II Aero-allergen sampling Correspondence to: Dr. F. Carswell, Institute of Child Health, Royal Hospital for Sick Children, Bristol BS2 8BJ (UK) Introduction The house dust mite Dermatophagoidespteronyssinus is widely present in the home. It has been implicated in the provocation of asthma attacks in atopic subjects. The faecal pellets produced by the mite contain one of the major mite allergens Derp I. These faecal particles may be inhaled by the patient, and environmental sampling should indicate the quantity. Although sampling of surfaces within the home gives results related to the presence of allergen in the air, no study has established the nature of the relationship between surface and air mite allergen. Material and Methods Air samples were collected from the bedrooms of 62 asthmatic children. Dust was collected from the mattress, duvet and carpet using a Hoover dustette vacuum cleaner for 2 min within a 0.25m2 template and from pillows for 30 s within a 0.06-m2 template [1]. A Casella air sampler was clipped to the pillow 12 in from the sleeping child’s head. It was switched on before the child went to bed and switched off after rising, each night for a 2-week period, to produce a cumulative sample. Forty-five air samples were collected and the results were expressed as nanograms per cubic metre of air. Petri dishes (8.5 cm diameter) were pretreated with 2% teleostean gelatine; one was exposed at floor level and one at about pillow height for 2 weeks [2]. Sixty-one data sets were collected. Data are presented as nanograms per day. Dust specimens were extracted with PBS/Tween/BSA. Derp I, Derp II and Feldl were measured using a two-site monoclonal antibody ELISA assay [3]. Spearman’s correlation coefficient and other non-parametric tests were used for statistical analysis. Results Forty percent of air samplers collected Derp I, 5% collected Derp II. In contrast 85% of the Petri dishes collected Derp I and 76% Derp II. The median allergen measurements are presented in