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PubMed1990

Dust mite assays in clinical allergy practice: mite antigen exposures among skin test positive patients in Kansas.

We have attempted to determine whether sensitive monoclonal antibody assays for Dermatophagoides mite antigens Der p I and Der f I can be carried out in a private clinical allergy practice laboratory, to ascertain incidence of significant home mite exposure in dust samples from patient homes in Kansas, and to consider whether such information impacts on patient management. We analyzed 152 dust samples from 62 patient homes. All patients were skin prick test positive for one or both common mite species available for skin testing, and had potentially relevant histories. Der p I and Der f I antigen levels were added together, and levels above 2 micrograms/g of dust were considered "positive." By this definition, elevated levels were found in at least one sample from 48 of 62 homes tested (77%); however, 61% of mattress samples tested, 41% of carpet samples, and 54.5% of furniture samples had levels below those considered likely to cause symptoms. Only 13 of 152 samples yielded Der p I levels above 2 micrograms/g. We conclude that monoclonal antibody assays for Der p I and Der f I antigens can be performed in a well-equipped office laboratory staffed by trained medical technologists, that Der f I is the predominant mite species in Kansas, and that data derived from mite assays may be important in treatment planning for patients suspected of having mite-related allergy symptoms.

Allergens↗
PubMedDate not supplied

Mite allergy in the tropics: sensitization to six domestic mite species in Cartagena, Colombia.

Sensitization to the domestic mites Blomia tropicalis, Chortoglyphus arcuatus, Lepidoglyphus destructor and Aleuroglyphus ovatus was investigated in 77 subjects with clinical symptoms of asthma and/or allergic rhinitis and a positive skin prick test (wheal > or = 3 mm) to Dermatophagoides pteronyssinus and/or D. farinae. Seventy patients were skin test-positive to D. pteronyssinus and 73 to D. farinae. Serum samples from 29 nonallergic, skin test-negative individuals were used as negative controls. Specific IgE was determined by RAST and the results expressed as the % of the total counts bound (% TCB). A positive result (> or = 1% TCB) to D. farinae was detected in 89.6% of subjects, to B. tropicalis in 80.5%, to D. pteronyssinus in 75.3%, to C. arcuatus in 71.4%, to A. ovatus in 68.8% and to L. destructor in 59.7%. None of the controls had a positive RAST to any of the mite species. Different IgE binding patterns were observed among these subjects, suggesting sensitization to unique as well as common allergens in the different mite species. Sensitization to Pyroglyphidae (D. pteronyssinus and D. farinae) and non-Pyroglyphidae mites (B. tropicalis, C. arcuatus, L. destructor and A. ovatus) is common among allergic individuals in Cartagena. Extracts of these mites may be needed for a more accurate diagnosis and effective treatment of respiratory diseases due to mite allergy in tropical environments.

Adult↗
PubMed1999

[House dust mite allergens and mite allergy in Copenhagen dwellings. A cross-sectional study].

The aim of the study was to investigate the influence of various environmental factors on occurrence of house dust mite allergens and the influence of allergen exposure on mite allergy. Ninety-two persons from a population study filled in a questionnaire, were skin prick and lung function tested and dust samples were collected from their mattresses for analyses. Two out of five patients with asthma had a positive skin reaction to house dust mite allergen in contrast to five out of 87 non-asthmatics. Fifty-nine per cent of the dust samples contained (group 1) mite allergen > 2 micrograms/g dust. Such mattresses were older (median 7 years, range 1-22) than mattresses with less allergen (median 4 years, range 1-20). In the six bedrooms reported to be humid or mouldy, mattresses contained high concentration of mite allergens. No other parameter investigated could predict the allergen contents. In almost all cases dust analyses are crucial to be able to advise patients with house dust mite allergy.

Air Pollution, Indoor↗
PubMed2002

Placebo-controlled study of the mite allergen-reducing effect of tannic acid plus benzyl benzoate on carpets in homes of children with house dust mite sensitization and asthma.

We studied the effect of a spray containing 1% benzyl benzoate, an acaricide, and 1% tannic acid ('Lowal'; a protein-denaturing substance), on concentrations of major allergens from house dust mite (HDM) species Dermatophagoides pteronyssinus and D. farinae (Der p 1 and Der f 1, respectively) in carpets. In a double-blind, placebo-controlled study with crossover design, 30 homes of children with HDM sensitization and asthma were included. All houses showed > or = 400 ng/g of Der p 1 + Der f 1 in carpet dust. The first treatment was performed on day 0 (group 1 active treatment, n = 15; group 2 placebo treatment, n = 15). After 2 and 8 weeks, dust samples were collected for quantification of mite allergens. After a 2-week washout period, the second treatment was performed (group 1 placebo treatment; group 2 active treatment). Again, carpet dust was collected after 2 and 8 weeks. Twenty-two of 30 families completed the trial: 14/15 in group 1 and eight of 15 in group 2. On day 0, there was no significant difference in mite allergen exposure between group 1 and group 2 (1,498 vs. 2,239 ng/g of Der p 1 + Der f 1, respectively). In group 1, the geometric mean for the difference of mite allergen concentration comparing day 0 and week 6 was 196 ng/g (95% CI: -7,161 and 8,401) for the first treatment (active) and 15 ng/g (95% CI: -1,079 and 1,292) for the second treatment (control). In group 2, the difference was 66 ng/g (95% CI: -398 and 1,515) for the first treatment (control) and 609 ng/g (95% CI: 186 and 9,264) for the second treatment (active). Comparing placebo and active treatment in total, there was a significant decrease following placebo treatment after 14 days (p = 0.026). After 8 weeks, active treatment was superior to placebo treatment (p = 0.049), but the allergen reduction achieved was < 20% (median 1,500 ng/g on day 0 vs. 1,250 ng/g after 8 weeks). We conclude that the slight mite allergen reduction on carpets achieved by the treatment with 'Lowal' is unlikely to achieve worthwhile clinical benefit either in the treatment of mite-sensitive patients or in primary or secondary prophylaxis.

Antigens, Dermatophagoides↗
PubMed1995

Portable dehumidifiers in the control of house dust mites and mite allergens.

Humidity is a decisive limiting factor for house dust mite (HDM) population growth and decreasing humidity may be the control method of choice. This study investigates the effects of portable dehumidifiers on the mite counts and concentration of the HDM allergen Der p I in the homes in northwest England. Mite counts and Der p I were measured in the paired dust samples collected by vacuuming a 1 m2 area of bedroom carpet, living room carpet, mattress and sofa for 2 min in six houses supplied with the dehumidifier and six control houses, before and 1, 2 and 3 months after the installment of dehumidifier. Temperature and relative humidity were recorded daily. There was no difference in mite counts in either of the groups throughout the study. Der p I decreased significantly in both groups and in all sampling sites, but no significant differences in the levels of reduction between the groups were found. Condensation was decreased in the dehumidifier group, but the level of indoor humidity capable of retarding mite population growth was not achieved. A single portable dehumidifier placed centrally in the house is unable to decrease indoor humidity to the level capable of retarding mite population growth and decreasing HDM allergens in the type of houses predominantly found in the northwest of England.

Allergens↗
PubMed2004

A review of the effects of impermeable bedding encasements on dust-mite allergen exposure and bronchial hyper-responsiveness in dust-mite-sensitized patients.

BACKGROUND: Sensitization and exposure to dust-mite antigens are causative factors in the development and exacerbation of asthma. Impermeable bedding encasements are considered a first-line treatment to reduce dust-mite antigen exposure in clinical asthma-management guidelines. Public-health recommendations for environmental asthma treatments should be based on the weight of evidence supporting the reliability of environmental interventions so that uncertainties regarding their effectiveness can be accurately communicated to patients, and so that limited public-health resources can be most effectively utilized. OBJECTIVE: To evaluate the strength of a clinical-trial evidence supporting the efficacy of bedding encasements as an asthma treatment. METHODS: A narrative review was conducted of all clinical trials involving bedding encasement for the treatment of asthma. Collective statistical analyses were also performed to characterize the quantitative effect of bedding encasement on dust-mite allergen exposure and bronchial hyper-responsiveness (BHR) when used by asthma patients. RESULTS: Over 30 clinical trials were reviewed. Of those studies reporting adequate exposure and BHR results, four reported significant reduction in dust-mite allergen exposure and concomitant BHR reduction in active-treatment groups using bedding encasements. In 10 studies, mite-allergen exposure was reportedly decreased during the study, but BHR was not changed in the active-treatment group or was reduced to a similar degree in the active-treatment and control groups. Five other studies reported a lack of significant effect of the intervention on exposure and BHR. Collective paired analyses found that the effect of bedding encasement on allergen exposure and BHR tended toward only a modest, non-significant improvement. Collectively, effects of bedding encasement on BHR and dust-mite allergen exposure were modestly correlated only when the baseline exposure was above 2 microg Type 1 antigen per gram settled dust. CONCLUSION: Although bedding encasement might be an effective asthma treatment under some conditions, when implemented in clinical trials by asthma patients, its effectiveness is inconsistent and appears to be, at best, modest. Therefore, its significance as a reliable asthma management modality for any individual asthma patient is uncertain. Where resource constraints are significant, targeting the use of variably effective interventions such as bedding encasements toward those patient sub-populations most likely to derive substantial benefit may gain the largest net public-health benefit.

Allergens↗
PubMed1997

The Melbourne house dust mite study: eliminating house dust mites in the domestic environment.

BACKGROUND: Hypersensitivity to house dust mite allergens is associated with increased asthma morbidity. Asthma severity appears to be related to the degree of mite allergen exposure. Short-term studies suggest that complete avoidance reduces disease severity. OBJECTIVE: The study was designed to assess the effect of different mattress covers and floor coverings on mite allergen concentrations in the homes of mite-sensitive children with asthma in the city of Melbourne, Australia. METHODS: Mite allergen Der p 1 concentration was measured on mattress covers, mattress surfaces, and carpeted and uncarpeted floors in 107 dwellings; and measurement was performed on three occasions over a 5-month period. After the first sampling, all mattress covers and impermeable encasements were permanently removed. RESULTS: The initial geometric mean concentrations of Der p 1 (micrograms per gram of fine dust) from the surfaces of sheepskin, wool, and cotton mattress coverings were greater than those from the surfaces of impermeable mattress encasements (116, 113, and 19 vs 0.4) (p < 0.001); corresponding concentrations on the underlying mattresses were 142, 38, 20, and 0.6, respectively (p < 0.05 to 0.001). At the end of the study these mattress surface concentrations were 79, 65, 9.7, and 3.1, respectively. In 24 dwellings an uncarpeted room was adjacent to a carpeted room. At each visit the concentration of Der p 1 in uncarpeted rooms was below the reported threshold for sensitization and significantly less than that in the adjacent carpeted room. CONCLUSION: In homes of children with asthma, "asthmogenic" concentrations of Der p 1 were found on nonencased mattresses and carpeted floors, but the use of impermeable mattress encasements and carpet exclusion were associated with concentrations of Der p 1 below the reported threshold for sensitization.

Adolescent↗
PubMed2006

A house dust mite allergen homologue from poultry red mite Dermanyssus gallinae (De Geer).

Tropomyosin is an allergenic, actin-binding protein and a proposed vaccine candidate from several species of parasite. Tropomyosin cDNA, obtained by polymerase chain reaction (PCR) amplification from Dermanyssus gallinae RNA, encoded a predicted protein with 89% and 88% identity to tropomyosins from the ticks Boophilus microplus and Haemaphysalis longicornis, respectively, and 85% identity to the house dust mite (HDM) tropomyosin Der p 10. Mouse antibodies raised against HDM tropomyosin reacted with a band of 38 kDa on Western blots of D. gallinae extract, consistent with the molecular masses of acarine tropomyosins and the putative product of the cDNA encoding D. gallinae tropomyosin. When the same preparation of D. gallinae proteins was used in Western blots with serum from infested hens, the IgY component of the serum bound to a number of mite proteins, but not to tropomyosin, indicating that hens are not directly exposed to this allergen during a natural infestation. Immunolocalization of tropomyosin in mites indicated a ubiquitous distribution of the molecule in mite tissues. Immunolocalization and Western blotting also indicated that poultry red mites ingest host IgY.

Allergens↗
PubMed1998

The combined influence of immunotherapy and mite allergen reduction on bronchial hyperresponsiveness in mite-sensitive asthmatic children.

UNLABELLED: Encasings for mattresses, blankets and pillows in combination with mite allergen reduction on the floor have proved effective in reducing bronchial hyperreactivity of mite-allergic children. We studied the effect of combining the use of encasings with specific immunotherapy in comparison to the use of encasings alone (control group). Twenty mite-allergic children (Skin Prick Test, RAST, mean age 10 years) with asthma and high domestic mite allergen exposure ( > 2 microg Der p 1 + f 1/g mattress dust) were included in our study. The concentration of these major allergens as well as specific and nonspecific bronchial hyperreactivity (PC20 FEV1 histamine) were assessed before, 6 months after and 1 year after start of treatment. All children received elongated polytetrafluorethylene (ePTFE; Goretex/Intervent Allergy Bedding System) encasings. A subgroup of eight children were treated additionally by specific immunotherapy with a partially purified mite extract (ALK Scherax) and a maximum dose of 100000 SQ-U Der p + f. Initially both groups were comparable with respect to the parameters assessed. In 80% of children, encasings reduced Der p 1 and Der f 1 concentrations on the mattress to below 3% of the initial values (P < 0.01). The median reduction was 99%. PC20 FEV1 histamine increased from 0.4 to 1.4 mg/dl (median) in the combined group with immunotherapy and encasings (P < 0.05) and remained essentially unchanged in the control group. PC20 FEV1 Der p did not increase significantly in either group. CONCLUSION: Specific immunotherapy with allergen extracts is an effective adjunct to encasings. Encasings, a key factor for reducing Der p 1 and Der f 1 on the mattress, should be used in combination with other avoidance measures (e.g. removal of carpets) in order to improve allergen-induced bronchial hyperreactivity.

Adolescent↗
PubMed1988

Prospective study on immunologic changes induced by two different Dermatophagoides pteronyssinus extracts prepared from whole mite culture and mite bodies.

Twenty-four children with bronchial asthma and hypersensitivity to Dermatophagoides pteronyssinus by skin titration, specific serum IgE, leukocyte histamine release, and bronchial challenge test were selected for immunotherapy with two partially purified mite extracts. On the basis of age and allergen-specific IgE responses, patients were randomly divided for treatment with either an extract prepared from whole mite culture (WMC) or from purified mite bodies (MB). The content of major allergens was quantified for both extracts. The allergen dose administered during immunotherapy was increased up to the highest tolerated dose. The mean cumulative dose of Der p I was 98.9 micrograms for the WMC-treatment group and 76.7 micrograms for the MB-treatment group. Small, but statistically significant, decreases in RAST and crossed radioimmunoelectrophoresis responses to major allergens were recorded after 2 years of treatment. A small increase in specific IgG1 and a large persistent increase in specific IgG4 was recorded in both groups. There was a significant decrease in allergen-specific bronchial sensitivity, skin reactivity, and leukocyte sensitivity in both treatment groups. Between both groups, changes in the different parameters were not significantly different. Our data indicate that immunotherapy with both partially purified house dust mite extracts, WMC, and MB leads to a decrease in allergen-specific IgE responses and induce a response in specific IgG4. Both extracts are comparable in modulating leukocyte and skin sensitivity, as well as bronchial reactivity to mite allergens.

Allergens↗
PubMed1993

Mite asthma in childhood: a study of the relationship between exposure to house dust mites and disease activity.

BACKGROUND: Children with asthma are commonly sensitized to the house dust mite. METHODS: We took monthly measurements from July to December of the amount of mites in the mattresses of asthmatic children and correlated them with symptom score, pulmonary function, and airway hyperreactivity to methacholine. RESULTS: In spite of the high number of Dermatophagoides pteronyssinus throughout this period, symptom and treatment scores, as well as PC20 to methacholine, worsened during the months of September and October. CONCLUSIONS: It is concluded that when asthmatic children allergic to mites are exposed to high levels of mite allergen, the number of mites in the mattress dust no longer correlate with increased symptoms, and that other factors are more likely to be associated with exacerbation.

Adolescent↗
PubMed2001

Emission of volatile organic compounds by apple trees under spider mite attack and attraction of predatory mites.

Emission rates of volatile organic compounds (VOCs) from Pirus malus L. subsp. mitis (Wallr.) var. Golden Delicious and var. Starking attacked by the phytophagous mite Panonychus ulmi Koch, and their attractiveness to the predatory mites Amblyseius andersoni Chant and Amblyseius californicus McGregor, were studied during three years. A large variability was found in the emission of individual VOCs depending on the infestation, the apple tree variety and the date. There were larger total VOC emission rates and larger total VOC leaf concentrations in apple trees attacked by phytophagous mites, especially in the var. Starking. In infested trees of this variety, there were also more predatory mites. An olfactometer assay showed that predatory mites preferentially chose branches infested by Panonychus ulmi (85% went to infested branches vs 15% to uninfested control branches) indicating that volatiles may be used as cues to find their prey.

Animals↗
PubMed2001

Seasonal occurrence of specialist and generalist insect predators of spider mites and their response to volatiles from spider-mite-infested plants in Japanese pear orchards.

In two adjacent Japanese pear orchards (orchards I and 2), we studied the seasonal occurrence of the Kanzawa spider mite. Tetranychus kanzawai, and its predators. Also the response of these predators to the volatiles from kidney bean plants infested with T kanzawai was investigated using trap boxes in orchard 1. The mite density in orchard 1 was unimodal. with one peak at the end of August. In this orchard, population development of the specialist insect predators, Scolothrips takahashii, Oligota kashmiria benefica and Stethorus japonicus was almost synchronized with that of the spider mites. These predators disappeared when the density of their prey became very low in mid-September. Both S. takahashii and O. kashmirica benefica abruptly increased in number in orchard 2 when the spider mite population in orchard 1 decreased. These results suggested that some of the predators migrated from orchard 1 to orchard 2. In this period, predator-traps with T kanzawai-infested bean plants attracted significantly more S. takahashii than traps with uninfested plants. Very few individuals of S. japonicus and O. kashimirica benefica were found in the traps, despite their abundance in orchard 1. The generalist insect predator, Orius sp., was attracted to the traps throughout the experimental period irrespective of the density of spider mites, although this predator was never observed inside the orchards.

Animals↗
PubMed2004

Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

Animals↗
PubMed2002

Sensitivity patterns to house dust mites and forage mites in atopic dogs: 150 cases.

This study investigated intradermal test reactions to extracts of six species of mites in 150 dogs with atopic dermatitis. At least one positive reaction was seen in 120 animals (80%). Dermatophagoides farinae attracted the highest number of positive reactions (108 dogs, 90% of dogs and 72% of atopic dogs showing positive reactions). Positive reactions to other mites were not uncommon, with many dogs testing positive for Dermatophagoides pteronyssinus (32% of dogs tested), Acarus siro (35%), Tyrophagus putrescentiae (30%), Glycyphagus domesticus (27%) and Lepidoglyphus destructor (23%). Sensitivity to D. farinae alone occurred commonly (57% of cases), but multiple sensitivities were seen frequently with the other mites. Cases of sensitivity to only one mite were also seen: D. pteronyssinus (five cases), T. putrescentiae (one case) and G. domesticus (one case). Further studies are needed to appreciate more clearly the precise role played by the different species of mite in canine atopic dermatitis.

Allergens↗
PubMed1999

Do mite avoidance measures affect mite and cat airborne allergens?

BACKGROUND: Effective mite allergen avoidance measures are presumed to reduce airborne allergens yet the quantity in the air is rarely measured. OBJECTIVE: To monitor airborne allergen during a placebo-controlled mite allergen avoidance study. METHODS: Bedrooms of 56 atopic asthmatic children were randomly allocated to hot washing and encasing covers + acaricide (active regime) or placebo treatment. Dust was collected from the mattress, bedding and carpets; airborne allergen was measured using Casella samplers and dust settling in open Petri dishes. Der p 1, Der p 2 and Fel d 1 were measured. RESULTS: After 24 weeks of mite allergen avoidance the Casella air-samplers collected Der p 1 less frequently in active than placebo-treated bedrooms (0 vs. 29%, P<0.05) and Petri dishes in the active group collected less than baseline (0.2 vs. 0.6 ng/day P<0.05). Homes without cats had less cat allergen than cat-owning homes and when actively treated for 24 weeks showed a greater reduction (P = 0.03) in mattress cat allergen than the placebo group. CONCLUSION: Encasing covers and hot washing of bed linen reduced mite aeroallergen (and mattress cat allergen in the absence of cats). This could mean dual benefits to a patient sensitive to both mite and cat.

Air Pollutants↗
PubMed1995

Rapid house dust mite (Acari: Pyroglyphidae) and storage mite (Acari: Glycyphagidae and Acaridae) allergen test.

Ten years ago a simple technique was described for detecting guanine from house dust mite excretions. The level of guaninine correlated well with the level of house dust mite allergens. Detection of storage mites is becoming more and more important, and these mites also produce guanine. Therefore, the above-mentioned technique provides a good indication of levels of storage mite allergens.

Allergens↗
PubMed1993

Trypsin-like protease of mites: purification and characterization of trypsin-like protease from mite faecal extract Dermatophagoides farinae. Relationship between trypsin-like protease and Der f III.

A serine protease from mite faecal extract, Dermatophagoides farinae, was purified using DEAE-Sephacel anion exchange chromatography and Superdex 75 pg gel chromatography. The molecular weight of this protease was 34 kD on SDS-PAGE under reducing conditions. The optimal pH and temperature of the protease were 8.0 and 47 degrees C, respectively. In addition, this protease cleaved arginyl or lysyl residue containing substrates selectively and was only inhibited by aprotinin, FUT-175, and soy bean trypsin inhibitor and not by chymostatin, E-64 and iodoacetic acid. These results show that our purified serine protease belongs to the trypsin-type. Purified trypsin-like protease was shown to be allergenic by enzyme-linked immunosorbent assay. Antigenicity of trypsin-like protease was completely different from those of Der f I and Der f II. Both, 20 N-terminal amino acid sequence and amino acid compositions of the purified protease were very similar to those of Der f III. Good similarities were found between trypsin-like protease and Der f III concerning physicochemical properties such as molecular weight on SDS-PAGE and ammonium sulphate solubility. Summarizing the above data, it can be concluded that a trypsin-like protease from mite faecal extract is actually the Der f III allergen and that it may be involved in the digestive process of the mite as it was found not in mite body but in mite faeces.

Adolescent↗