Airborne Concentrations and Particle Size Distribution of Allergen Derived from Domestic Cats (Felis domesticus): Measurements Using Cascade Impactor, Liquid Impinger, and a Two-site Monoclonal Antibody Assay forFel dI

Abstract

The recent development of a sensitive two-site monoclonal antibody immunoassay for the major cat allergen (Fel d I) has made it possible to make accurate measurements of airborne cat allergen using low volume samplers that do not disturb the room. Houses with cats had from 2 to 20 ng Fel d I/m3 air compared with less than 0.2 ng/m3 in houses without cats. Using a cascade impactor and a multistage liquid impinger, the particle size distribution of airborne Fel d I in nine houses was 75% on particle greater than or equal to 5 microns in diameter and 25% (range, 10 to 62%) on particles less than or equal to 2.5 microns. In a cat vivarium with 12 cats, the air contained 40 ng Fel d I/m3, but less than 2% was detected on particles less than or equal to 2.5 microns. The air exchange rate in the vivarium (approximately 15 changes/h) appears to be the major difference from domestic houses (less than 0.5 changes/h). Repeated studies in one house confirmed a very high proportion (approximately 60%) of Fel d I on small particles. During domestic cleaning, the levels of small particle allergen in this house approached those produced by a nebulizer for bronchial provocation, i.e., 40 ng/m3. These results show unequivocally that significant airborne Fel d I is associated with small particles, which remain airborne for long periods. These findings are strikingly different from previous results obtained with airborne dust mite allergen. The results provide an explanation for the distinctive rapid onset of asthma or rhinitis in patients allergic to cats and a basis for designing a policy to reduce airborne allergen in houses with cats.

Validity of the interview on pets kept at home for predicting the actual domestic expsoure to their specific allergens. Krakow inner city area study

“…Concentrations of the pet allergens were correlated between sampling sites within homes. The correlation between pet allergens collected from various house sites results from the fact that Can f 1 and Fel d 1 are associated with small dust house particles that remain airborne for long periods [29,30] and this helps the allergens circulate and settle on various places and domestic furniture throughout a house. Although the distributions of each allergen throughout the homes were not very much different, the highest concentrations of Can f 1 and Fel d 1 were usually found on the beds and bedroom floor.…”

Allergy markers in respiratory epidemiology

“…For example, cat allergen is airborne on smaller particles and remains airborne longer [72]. Currently, airborne measurements of exposure are considered too complex for epidemiological studies [72,74]. Exposure to allergens may not only increase the risk of sensitization, but may also trigger episodes of disease of those sensitized.…”

Differences in sensitization rates to outdoor aeroallergens, especially citrus red mite (Panonychus citri), between urban and rural children

“…Features of modern-day housing, such as the trend toward houses that are sealed against cold winters and, as a result, are poorly ventilated, have led to increased exposure to house dust mites and allergens shed by animals. 9,10 In this study, the most common sensitizing allergens among the children living in the rural areas with citrus farms were D. pteronyssinus (26.6%), D. farinae (22.6%), CRM (14.1%), cockroach (13.3%), and Japanese cedar pollen (10.3%), but sensitization rates to outdoor pollens (except Japanese cedar pollen) were very low. In contrast, the sensitization rates to tree pollens (except Japanese cedar pollen and weed pollens) were higher among the urban children compared with the rural ones.…”