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PubMed1994

House dust mite allergen levels in a Singapore hospital.

House dust mite allergens constitute one of the most important allergens in house dust. In this study, the levels of two common dust mite allergens, Der p I and Der f I, in a general hospital in Singapore were evaluated. Our results showed that these allergens were detected in 42/74 (or 57%) of the dust samples. Der p I was found to be the predominant allergen detected (p < 0.001). The allergen levels were, however, low with only 1/74 having a Der p I concentration above 2 micrograms g-1 dust. None of the samples had Der f I concentrations above this level. Of the various niches studied (mattresses, pillows, sofas, carpets, blinds and floors), the blinds and floors had the lowest concentration of allergen (p < 0.05). These low levels in the hospital compared to homes were attributed to the vigorous cleaning schedule in the hospital, the use of plastic to encased mattresses and pillows, vinyl covered sofas and vinyl lined floors. These practices may be adopted in the home as a means to reduce mite allergen exposure.

Air Conditioning↗
PubMed1995

Efficacy of the acaricide: acardust for the prevention of asthma and rhinitis due to dust mite allergy, in children.

A double blind, randomized, comparative study versus placebo, was done during 6 months in 32 children, aged 4-12 years, who suffer from either allergic asthma or rhinitis or both, slept in a bedroom rich in dust mite, have well documented allergy solely to house dust mite (H.D.M.), and a condition severe enough to require continuous medication. After thorough cleaning, their bedrooms were sprayed on day 0 and day 90 with the total content of a canister containing either Acardust or Placebo. Rooms were cleaned regularly throughout the study period. Each child completed an individual daily score card (scales from 0-3) for asthma, and rhinitis symptoms, medication taken, and any additional symptoms. Peak flow was recorded twice weekly. All the children were examined every month (at the clinic) when also PFF, FEVI, doctor's and patient's opinion of clinical symptoms were recorded according to the same scale (0-3) and dust samples from child's bedroom were examined for H.D.M. antigen content. At day 0, 90 and 180, total IgE and dust mite specific IgE determination was done. At the end of the study, patient's and doctor's opinion about the spray's efficacy were recorded on a scale from 0-3. The results were in favor of Acardust for asthma, according to patient's opinion (p = 0.001), doctor's opinion (p = 0.04) and individual score cards (p = 0.03), and for nasal secretion (p = 0.01), sneezing and lacrimation (p = 0.02); concurrent medication dropped significantly (p = 0.01) in the Acardust group. No side-effects were reported. We consider Acardust a safe and valuable preventive treatment in H.D.M. allergy.

Allethrins↗
PubMed1993

House dust mite allergy in Calcutta, India: evaluation by RAST.

A significantly elevated (above 300 U/mL) serum IgE level was found in 97 of 105 dust-sensitive asthmatic patients of Calcutta and the mean value (1002 +/- 614 U/mL) was significantly higher (P << .001) than the control sera. RAST results indicate a higher sensitivity (84.76%) to house dust and house dust mites (Dermatophagoides supp) either alone or in combination with each other. Among positive samples, 79.77%, 71.91%, and 88.76% showed the presence of allergen specific IgE antibodies against house dust (HD), D. pteronyssinus (DP), and D. farinae (DF) mite antigens, respectively. The study highlighted the superiority of D. farinae antigen as a potent allergen in house dust of Calcutta over others and the mites and house dust possibly had a common allergen. The present investigation indicates that RAST sensitivity was independent of age and sex of patients (P > .05). The frequency of RAST sensitivity was observed to be greater in patients suffering for longer durations.

Adolescent↗
PubMedDate not supplied

[An attempt at an economic assessment of the damage caused by allergenic house dust mites].

Mites have been found to contribute to the etiology of some allergic diseases most common in Uzbekistan. The economic losses caused by atopic dust-borne asthma have been estimated. The losses due to damage to the national income, which are done by disability and to the direct and indirect expenses on treatment and disability allowance have been calculated and compared. Such an attempt is useful to calculate the profitability of prevention of domestic dust mite-caused diseases and of the mite control measures.

Adolescent↗
PubMedDate not supplied

Storage mites and their role in the onset of asthma and oculorhinitis among cattle farmers in north-east Italy.

The results are reported of an epidemiological study carried out in the province of Treviso in north-east Italy. The research was designed to ascertain the sensitization, through an IgE mechanism, to the main allergens present on cattle farms. Also reported are the results of a mite survey undertaken in ten barns in the same region. Investigations revealed a significantly larger degree of sensitization to storage mites among cattle farmers than in the control subjects. This sensitization was well correlated with mite species to be found in cattle barns. However, the frequent co-sensitization to Dermatophagoides offers a topic for further study.

Adolescent↗
PubMedDate not supplied

[The development of a method for isolating and the study of the properties of an extract of the allergens from granary mites].

The method for obtaining allergenic extracts from T. putrescentiae bodies has been developed. As nutrient medium for the cultivation of these mites oat flour has been selected: it has no allergenic cross-reactive properties with T. putrescentiae. Some physico-chemical properties and specific activity of allergenic extracts obtained from these mites were studied. Protein content in these extracts has been found to vary from 0.93 to 0.26 mg/ml, depending on extraction conditions. Protein constitutes 1.5-30.0% of the dry substance of the allergen. After lyophilization the allergen becomes grayish-white powder, readily soluble in water and aqueous saline solutions. In addition, allergenic extracts from T. putrescentiae have pronounced capacity for binding specific IgE antibodies in the sera of patients sensitized to storage mites of this species, which has been confirmed by RAST inhibition and ELISA. Lyophilization produces no changes in the properties and activity of T. putrescentiae allergenic extracts.

Allergens↗
PubMed1994

[House dust mite allergens and COPD in children; a case-control study].

OBJECTIVE: To determine the relationship between mite allergen (Der p I) concentrations in house dust and presence of chronic respiratory symptoms in children. DESIGN: Case control study. SETTING: The provinces of Gelderland and North-Holland in the Netherlands. METHOD: Questionnaires were handed to pupils of 38 schools to take home; about 6000 were returned (80% response). A home visit was paid to 259 children with chronic respiratory symptoms ('cases') and to 257 symptom-free 'control' children. Using an enzyme immunoassay the Der p I concentrations of living room floor dust, bedroom floor dust and mattress dust were determined. Specific IgE was determined in serum. RESULTS: Der p I concentrations higher than 2000 ng/g were found in 86% of the dwellings and concentrations higher than 10,000 ng/g in 55%. Cases were exposed to lower Der p I concentrations than controls. However, cases sensitised to dust mites were exposed to higher Der p I concentrations than non-sensitised cases, both living in homes where no allergen avoidance measures had been taken in the past. CONCLUSION: Exposure to Der p I in the home was associated with sensitisation to dust mites in children with chronic respiratory symptoms living in homes where no allergen avoidance measures had been taken.

Allergens↗
PubMed1993

Atopic dermatitis: role of food and house dust mite allergens.

OBJECTIVE: The aim of this study was to evaluate the humoral immune response to cow milk (CM) protein, soya protein, and house dust mites in a group of 64 CM-fed infants, who had atopic dermatitis as the sole atopic manifestation, by measuring not only IgE but also specific IgG antibodies (Ab) against bovine beta-lactoglobulin, soya flour aqueous extracts, and Der P1 antigens. METHODS: A CM-free diet (Nan HA, Nestle) was given to these 64 CM-fed infants and the sensitivity to CM proteins was established by a positive challenge test with the offending food in improved infants. The serum was obtained just before the start of the CM-free diet, at the first consultation. The patients were classified into two groups according to their clinical response to the hypoallergenic formula. RESULTS: Thirty-one infants (group 1) improved dramatically (positive challenge test), and 33 (group 2) did not improve with the exclusion diet but did improve after eviction of dust-producing items in the environment. The two groups were different in terms of their total IgE immunoglobulin concentration (higher in group 1, P < .05) and concentration of specific IgE Ab against CM protein (more frequent in group 1, P < .01). The IgG Ab concentrations against beta-lactoglobulin, the major CM antigen (P < 10-4), and against soya protein (P < .01) were significantly more elevated in the group improved by the diet, with a threshold above which the response to the exclusion diet could be predicted as positive. On the contrary, the level of specific IgG Ab against house dust mites was four times higher in group 2 than in group 1. Twenty-nine of the 33 infants of group 2 improved after eviction of dust-producing items in the environment. CONCLUSIONS: It is proposed that specific IgG Ab concentrations against beta-lactoglobulin, soya protein, and Der P1 antigen be determined in infants and children suffering from atopic dermatitis as a means of predicting the response to an exclusion diet, and a possible role of house dust mites in the pathogenicity of the disease is suggested.

Animals↗
PubMed1993

Effect of microbial and mite proteases on low and high molecular weight kininogens. Generation of kinin and inactivation of thiol protease inhibitory activity.

Kinin release from guinea pig plasma high molecular weight kininogen (HMWK) induced by various microbial and mite proteases has been demonstrated previously (Molla, A., Yamamoto, T., Akaike, T., Miyoshi, S., and Maeda, H. (1989) J. Biol. Chem. 264, 10589-10594; Maruo, K., Akaike, T., Matsumura, Y., Kohmoto, S., Inada, Y., Ono, T., Arao, T., and Maeda, H. (1991) Biochim. Biophys. Acta 1074, 62-68). In this paper, we describe the effects of various microbial and mite proteases on low molecular weight kininogen (LMWK) and HMWK from human plasma. A protease from the house dust mite Dermatophagoides farinae (Df-protease) directly liberated kinin from both LMWK and HMWK to a significant degree. The Km, kcat, and kcat/Km values for kinin generation from LMWK were 3.24 microM, 0.61 s-1, and 1.9 x 10(5) M-1 x s-1, respectively, and those for kinin generation from HMWK were 0.56 microM, 0.12 s-1, and 2.1 x 10(5) M-1 x s-1, respectively; kcat/Km values for Df-protease were comparable with that for glandular kallikrein. In contrast, microbial proteases showed only weak kinin-releasing activity from both human plasma kininogens. Four of ten different microbial proteases liberated kinin from LMWK, and only serratial 56-kDa protease released kinin from HMWK. Furthermore, Df-protease markedly inactivated the thiol protease inhibitory activity of LMWK and HMWK, whereas all microbial proteases (as well as the endogenous protease trypsin) did not affect this inhibitory activity of both kininogens from human plasma.

Animals↗
PubMed1993

Relationship between dust mite allergen and human IgA in house dust samples.

Previous investigators have mentioned that human IgA is found in house dust. IgA has also been reported to be present on human skin and hence in human dander. If human dander is the primary source of food for house dust mites, a relationship would be expected between IgA and dust mite allergen (Der f I) concentrations. We wished to learn whether IgA was consistently detectable in house dust and whether IgA and dust mite allergen concentrations were related. Dust samples were collected from the bedrooms of infants enrolled in a prospective study designed to evaluate the relationship between early allergen exposure and childhood allergic disease. One hundred eighty samples were studied: 50 samples were the initial samples collected from the first 50 infants enrolled, 120 samples were monthly samples obtained from 10 other homes, and 10 additional samples were randomly selected for extraction in a nonprotein containing buffer to determine the percentage of total extractable dust protein contributed by IgA. Finally, nine commercial house dust extracts were studied to learn whether they were similar to the dust samples from study houses. Enzyme linked immunosorbent assays (ELISAs) were used to measure human IgA, human secretory IgA (sIgA) and Der f I concentrations in all of the dust extracts. We found that IgA was consistently present in house dust samples ranging from 3.2 to 2,396 micrograms of IgA per gram of dust. A strong correlation (r = .90) was found between IgA and sIgA concentrations. IgA constituted 0.27% to 6.04% of the total protein in dust samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution↗
PubMed1995

[Nasal smear cytology in bronchial asthma: correlation of appearance and numbers of nasal smear mast cells, eosinophils or basophils and serum IgE antibodies to house dust mite in patients with bronchial asthma].

Nasal smear cytology was studied in pediatric patients with bronchial asthma with special reference with IgE RAST to house dust mite, Dermatophagoides pteronyssinus (Dp). Results obtained were as follows: (1) Numbers of eosinophils on the nasal smear correlated well with Dp RAST score, (2) mast cells were detected before Dp RAST becoming positive and appearance of eosinophils, (3) basophils appeared after detection of eosinophils and only in patients with nasal smear eosinophils. These results suggest that mast cells are the early marker for allergic inflammation and basophils and eosinophils appear in association with overt sensitization with house dust mite in house dust mite-sensitized asthmatic patients.

Adolescent↗
PubMed1995

[Chronological analysis of eosinophil infiltration in mite-allergen induced dermatitis in atopic patients].

To elucidate the active process of eosinophil infiltration in atopic dermatitis (AD), we performed patch testing using crude mite allergens on normal-appearing skin in adult AD patients with high levels of mite-specific IgE antibodies and analyzed positive reaction sites chronologically by histological and immunohistological methods. Positive reactions were observed in 6 out of 9 AD patients (66.7%), whereas none of 7 non-AD control subjects showed positive reactions. Skin biopsies were obtained from positive reaction sites at 2,6,12,24 and 48 hours after allergen challenge. Eosinophils were seen within postcapillary venules at 2 hours, followed by increased perivascular eosinophil infiltration at 6 hours which peaked at 24 and 48 hours. Epidermal eosinophilic spongiosis was also observed at 48 hours. The majority of infiltrating eosinophils showed positive reactions for BMK-13 and 15-59% of them were EG2 positive activated eosinophils. BMK-13, EG2 and anti-EP positive reactions were scattered throughout connective tissue and their areas were time-dependently increased. These findings suggest that eosinophil transmigration and activation play an important role in initiating early AD lesions induced by transepidermal mite allergen permeation.

Adult↗
PubMed1995

The evaluation of skin prick test in house dust mite allergy in Calcutta, India.

Immediate type allergy towards house dust and house dust mites was measured in 188 dust-sensitive asthmatic patients in and around Calcutta by using the skin prick test. Of the 131 positive patients, 82% reacted to Dermatophagoides mites, 80% to D. farinae, 46% to D. pteronyssinus, and 43% to both species of mites. Sixty-two per cent of the positive patients showed strong skin reaction to D. farinae as compared to 32% to D. pteronyssinus. Skin reaction (positive/strong) was highest in D. farinae as compared to other allergens tested in the present study. Skin test results were also analysed in relation to patients' age, sex and duration of disease.

Adolescent↗
PubMed1996

Study on the ability of a new barrier to reduce airborne mite allergens.

Environmental control, especially means for blocking the release into the air of mite allergens embedded in padded furniture (mattress, pillows), represents the first important step in the treatment of IgE-mediated allergic diseases. New to the market is a home hygiene spray that creates a protective barrier on padded furniture and is thereby able to contain the dispersion into the air of allergic particles. We tested the effectiveness of the spray in vitro. Since mites, especially D. Pteronyssinus, are considered the foremost allergens, we verified the ability of the invisible barrier to impede the diffusion of the allergen and the mobile forms of these mites (Der p 1, Der 2). The product under exam created a barrier that totally blocked the passage of mobile forms and almost totally prevented the passage of allergens (> 99%).

Aerosols↗
PubMed1977

Tropical rat mite dermatitis.

We had a patient with dermatitis caused by the bite of Ornighonyssus bascoti (Hirst), commonly referred to as the tropical rat mite. The bite of this mite resulted in a severely pruritic papular dermatitis in our patient. Accurate identification of the mite indicated the presence of rat infestation.

Aged↗
PubMedDate not supplied

Quality parameters for the production of mite extracts.

Mites present in house dust are of great etiological importance in type I hypersensitivity, with those belonging to the Dermatophagoides genus (D. pteronyssinus and D. farinae), of the Pyroglyphidae family, being the most frequent and principal source of allergens. For the production of allergenic extracts destined for specific diagnostic and treatment purposes of allergic diseases, the culture of such mites is absolutely necessary. In accordance with studies carried out in our laboratories to obtain adequate extracts, one must bear in mind the culture mite phase. Three growth phases have been distinguished for both species: latency phase (F1), growth phase (F2) in which the allergenic proteins are expressed with greater intensity, and death phase of the culture (F3). In the same study, the biological standardization of the extracts demonstrated that those produced from the maximum growth phase gave both in vitro and in vivo results, at least three times more sensitive than those from the other phases. We checked the reproducibility of the production method, obtaining different batches in similar conditions with a high homogeneity regarding allergenic activity. The sensitivity and specificity of the allergenic extracts depends just as much upon the production method as the standardization method. During the biological cycle of Dermatophagoides in culture, it is only from the maximum growth phase (F2), that allergenic extracts with an excellent diagnostic value, high sensitivity and specificity, can be obtained.

Allergens↗
PubMed1997

Characterization of the allergen Der f 7 from house dust mite extracts by species-specific and crossreactive monoclonal antibodies.

BACKGROUND: The group 7 mite allergens react with IgE in 50% of sera from allergic patients. OBJECTIVE: To determine the molecular and antigenic characteristics and heterogeneity of Der f 7 in mite extracts. METHODS: Monoclonal antibodies (MoAbs) produced from mice immunized with recombinant Der f 7 were examined for crossreactivity to Der p 7 and then used for immunoblotting of 1 and 2-D gel electrophoresis. Deglycosylation was studied with N-glycosidase-F and N-terminal sequencing by Edman degradation. The epitopes of the monoclonal antibodies were compared by cross-inhibitory immunoassays. RESULTS: Immunoblotting of D. farinae extracts with all the anti Der f 7 MoAbs showed major reactivities at 31, 30 and 25 kDa. The strongest immunostaining was at 25 kDa which contrasted with Der p 7 where the 31 and 30 kDa bands were strongest. The relative strength of staining however varied between extracts. The 31 and 30 kDa components were glycosylation products of the 25 kDa form which had the N-terminal sequence predicted from cDNA analysis. Two MoAbs stained an 18 kDa band consistent with a degradation product. The 2-D gels showed that different components with pIs from 5.6-6.4. Both species-specific and Der p 7 crossreactive MoAbs were produced and a two-site ELISA assay for detecting group 7 allergen was developed with MoAbs recognizing different epitopes. CONCLUSIONS: Der f 7 has been defined by its natural N-terminal sequence and MoAbs. It apparently exists as different glycosylation and degradation products in mite extracts, the relative abundance of which differs with different preparations. A two-site ELISA to measure the allergen was developed.

Allergens↗
PubMed1997

Distribution and abundance of house dust mites, Dermatophagoides spp., in different ecological localities in Esna City, Kena Governorate, Egypt.

The distribution and abundance of house dust mites, Dermatophagoides spp. were studied in July, September and November, 1995 in three different localities in Esna City, Kena Governorate, Upper Egypt. During these months, 15 houses were sampled in each locality. 87% of riverside houses were infested with mites where D. pteronyssinus dominated (80%) over D. farinae. Sixty percent of the valley houses sampled were infested, where D. farinae was dominant (66%). Densities of both Dermatophagoides spp., were considerably higher in riverside than in valley houses. Live mites were not found in the lightly infested houses sampled in the desert area (54% positive). Relative humidity, which varied in houses located in different climatic localities in Esna City, was noted to be the principal limiting factor influencing the distribution and abundance of both species. Temperature did not appear to be an important factor influencing the distribution and abundance.

Animals↗