Measurement of allergens associated with dust mite allergy. II. Concentrations of airborne mite allergens (Der I and Der II) in the house

Comparative detection of mite allergens in house dust of homes in Moscow by enzyme-linked immunosorbent assay and acarologic analysis

The present study revealed that 73% of surveyed apartments in Moscow whose residents included children with the atopic form of bronchial asthma and sensitization to Dermatophagoides pteronyssinus allergens were infested with the pyroglyphid mites D. pteronyssinus and D. farinae. The number of mites in the surveyed apartments varied between 0 and 154 mites/g of dust for D. pteronyssinus and between 0 and 162 mites/g of dust for D. farinae. The levels of mite allergens in these apartments ranged from 0.5 to 165.8 micrograms/g for Der p I and from 0.3 to 91.3 micrograms/g of dust for Der f I. The Der p I allergen was found to predominate, and its concentration in one-third of the apartments was more than 10-fold greater than that of Der f I. Correlation between the number of pyroglyphid mites and the concentration of group I allergens was established for both D. pteronyssinus (r = 0.4932; P < 0.01) and D. farinae (r = 0.6748; P < 0.01). In most of the apartments, high and moderate levels of Der I allergens were detected.

Monoclonal antibodies to group II Dermatophagoides spp. allergens: murine immune response, epitope analysis, and development of a two-site ELISA

BACKGROUND

Group II allergens are a major cause of sensitization in patients allergic to mites. To facilitate the antigenic analysis of group II allergens and to develop improved methods of allergen detection, we compared IgG anti-group II antibody responses in inbred mouse strains and raised a panel of monoclonal antibodies (mAbs).

METHODS

IgE antibody responses were compared by antigen-binding radioimmunoassay. Epitope specificity of the mAbs was analyzed by two-site binding assays and by cross-inhibition radioimmunoassays.

RESULTS

Comparison of polyclonal IgG antibody responses in five BALB congenic strains showed that H-2d mice had poor responses, whereas H-2b and H-2k mice had strong, cross-reactive, IgG anti-group II responses. The specificities of nine anti-Der p II IgE mAbs raised in A/J mice were compared with specificities of seven mAbs produced previously. Most mAbs (11 of 16) recognized common epitopes on Der p II and Der f II: three were specific to Der p II, and two showed high binding to Der f II. Epitope analysis showed that the mAbs defined four cross-reactive, nonoverlapping sites on the group II allergens. Binding of several combinations of mAbs was compared, and a two-site ELISA for group II antigens was developed. Linear regression analysis showed an excellent correlation between results of this assay and group II radioimmunoassay of house dust samples (n = 40, r = 0.85, p < 0.001).

CONCLUSIONS

There are multiple cross-reactive B-cell epitopes on group II allergens. The group II ELISA has several important applications, including assessment of environmental allergen exposure, monitoring of the efficacy of avoidance procedures, and standardization of commercial mite allergen extracts.

Controlled exposure to mite allergen for a dose-finding of dimethindene maleate (DMM)

The aim of the study was to develop a laboratory system to challenge mite allergic patients with physiological concentrations of Der p I in order to evaluate the efficacy of antiallergic drugs in mite allergic patients. A double-blind, placebo-controlled, cross-over study was designed with three consecutive sessions. Twelve patients with proven sensitivity to dust mite were treated with a single dose of dimethindene maleate in a FOAD formulation (4 and 8 mg vs. placebo) 12 h before a long-term challenge with mite allergen Der p I in the Vienna challenge chamber. Challenge was performed with a constant concentration of 40 ng Der p I per cubic meter of air for 4 h. Nasal parameters were recorded at 15 min intervals during long-term challenge. In comparison to placebo, dimethindene leads to a statistically significant reduction (p < 0.05) of the nasal response at both concentrations tested. The house-dust mite model in the Vienna challenge chamber thus proved to be a useful tool for drug investigations in mite allergies.

Allergen exposure and control

Allergens produced by the house dust mites (family Pyroglyphidae) are probably the single most important allergens associated with asthma world wide. If exposure to these allergens in houses could be sufficiently reduced, then asthma symptoms may be markedly reduced and even prevented from being initiated. Only about half of the many attempts to reduce mite allergens in houses have shown any clinical benefit. One reason may be that exposure was not reduced enough--however exposure to mite allergens has never been measured in any trial. This review summarises previous allergen control trials and then provides an outline of allergen exposure, including the nature of exposure, the analytical methods available and the recognised risks of allergen exposure. This provides a perspective to evaluate the individual methods used to kill mites and to reduce exposure to the allergens. The object is to provide a framework to improve and develop allergen avoidance as an effective component of asthma management.

Environmental control of indoor air pollution

Indoor air pollution is becoming an increasing problem in industrialized countries. Most people spend their time indoors which results in chronic exposure to indoor allergens and irritants. New products have been introduced to the environment to which humans are not immunologically adapted. This article describes the main sources of indoor air pollution and the best ways to control exposure to indoor air pollutants.

Concentration of airborne mite allergens (Der I and Der II) during sleep

Using a low-noise air sampler and a sensitive radioimmunoassay, we measured the concentration of mite allergens in the air during sleeping with Japanese bedquilts (futon). The airborne allergen levels of Der I (Der p I plus Der f I) and Der II during sleep were 223 and 87.1 pg/m3 of air, respectively. These levels were about 10-fold higher than those during usual domestic life in the living room of the same houses. When the bedquilts were changed to new ones free of mite allergens, the airborne allergen levels of Der I and Der II were decreased to 11.5 and 12.0 pg/m3, respectively. This indicated that the mite airborne allergens during sleep were generated from the used bedding, not from the floor. We believe that exposure to airborne mite allergens during sleep might be an important factor in the development of mite allergies.

Airborne dust mite allergens: comparison of group II allergens with group I mite allergen and cat-allergen Fel d I

The form in which allergens become airborne is important because it may influence both symptoms caused by allergen exposure and methods used to reduce exposure. The group I allergens from dust mites only become airborne during disturbance and fall rapidly, which is in keeping with their being carried on fecal pellets. Their mean size is approximately 20 microns in diameter. By contrast, the cat-allergen Fel d I is airborne on particles varying from greater than 10 to less than 2 microns in diameter, some of which remain airborne even without disturbance. A second group of mite allergens, molecular weight 14,000, are equally important and are associated predominantly with mite bodies. With a monoclonal antibody-based assay and a cascade impactor, we have investigated the form in which group II mite allergens become airborne. The results reveal that these allergens only become airborne during disturbance and that they fall within 15 minutes. However, the mean size of particles carrying group II allergens appears to be slightly smaller than the mean size of particles carrying group I allergens. In addition, the quantities of group II allergen becoming airborne during disturbance (mean, 26 ng/m3) could not be explained by the quantity found in fecal particles. Thus, group II mite allergens become airborne in a form quite distinct from cat allergens and very similar to group I mite allergens; however, it appears unlikely that fecal particles are the main form in which group II allergens become airborne.

Exposure and sensitization to dust mite allergens among asthmatic children in São Paulo, Brazil

A group of 20 mite allergic asthmatic children aged 6-12 years old, living in São Paulo, Brazil, was studied regarding their degree of sensitization to house dust mites and exposure to mite allergens in their homes. In 18 out of 20 houses at least one dust sample was obtained which contained greater than 10 micrograms Der p I/g of dust. The highest levels of Dermatophagoides pteronyssinus allergens, Der p I and Group II, were measured in bedding samples (geometric mean 38.4 and 36.6 micrograms/g, respectively), followed by bedroom floor, TV room and kitchen. Mite allergen levels in Brazilian houses were as high as those reported to be associated with sensitization and acute attacks of asthma in other parts of the world. In keeping with previous reports that D. farinae is rarely found in Brazil, Der f I was undetectable or found in very low levels (less than 0.5 micrograms/g). Levels of cat allergen Fel d I of greater than 8 micrograms/g of dust were obtained only in 2 houses only. Cockroach allergen Bla g I was detected in five out of 20 houses. Levels of IgE antibodies to D. pteronyssinus were greater than 200 RAST U/ml in 19 out of 20 children (geometric mean 1588 RAST U/ml). IgE antibodies to cat, cockroach, A. fumigatus, ragweed and rye grass pollens were undetectable or less than 80 RAST U/ml. IgE antibodies to the mite Blomia tropicalis were also measured, and levels greater than 200 RAST U/ml were observed in 13 out of 20 sera.(ABSTRACT TRUNCATED AT 250 WORDS)