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PubMed2002

Morphological and molecular characterization of a new microsporidian species from the predatory mite Metaseiulus occidentalis (Nesbitt) (Acari, Phytoseiidae).

A new microsporidian species is described from the predatory mite Metaseiulus (formerly Typhlodromus or Galendromus) occidentalis (Nesbitt) (Acari, Phytoseiidae). The ultrastructure of this new species is presented together with the first molecular characterization for a microsporidium of mites. All stages of this new microsporidium are haplokaryotic and develop in direct contact with the host-cell cytoplasm. Sporogony is disporoblastic and spores are formed in eggs, immature stages, and adults of M. occidentalis. There are two morphological classes of spores, one with a short polar filament (3-5 coils) that measured 2.53 x 1.68 microm and one with a longer polar filament (8-9 coils) that measured 3.14 x 1.77 microm. Horizontal transmission of this new species occurs by cannibalism of eggs and other stages and perhaps involves the spores with the long polar filament. Spores with the short polar filament may play a role in autoinfection and vertical (transovarial) transmission that is highly efficient in transferring the microsporidium from adults to progeny. Analysis of the small subunit ribosomal DNA indicated that this species from M. occidentalis is most closely related to the Nosema/Vairimorpha clade of microsporidia. A conflict between the morphological and molecular data is discussed. The species is compared to previously described microsporidia of arachnids resulting in creation of Oligosporidium occidentalis n. sp. in the family Unikaryonidae.

Animals↗
PubMed1999

Heightened IgE response to mite antigens in inflammatory neuropathies.

In order to clarify the IgE response to common environmental antigens, we measured the serum total IgE and allergen-specific IgE in 50 patients with Guillain-Barré syndrome (GBS), nine patients with Fisher syndrome (FS), 14 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 18 patients with mononeuritis multiplex (MNM), 43 patients with neurodegenerative disorders and 82 healthy controls by ELISA. The total IgE level was significantly higher in patients with GBS (median = 135 U/ml, P<0.05), CIDP (median = 175 U/ml, P<0.05) and MNM (median= 199 U/ml, P<0.05), than in the healthy controls (median = 79 U/ml), but not in those patients with neurodegenerative disorders. The specific IgE to Dermatophagoides pteronyssinus was significantly higher in the patients with GBS (56%, P<0.01) and MNM (72%, P<0.005) than in the healthy controls (32%). The level of specific IgE to Dermatophagoides farinae tended to be higher in the patients with GBS than in the healthy controls (0.05<P<0.1). The patients with CIDP and MNM also showed a similar increase in the frequency of mite antigen-specific IgE. As a result, the heightened IgE responses to mite antigens may therefore in part be related to the mechanism of inflammatory neuropathies. On the other hand, such heightened IgE responses in these inflammatory neuropathies may be a reflection of Th2 cell overactivity, which may induce an intense synthesis of autoantibodies against the peripheral nerves.

Adolescent↗
PubMed1992

The distribution of cat and dust mite allergens on wall surfaces.

This study was undertaken to determine the distribution of cat and dust mite allergens on wall surfaces and to assess the value of wall-wipe samples as a measure of allergen exposure. Paired samples were collected from 31 homes, 20 homes with cats and 11 homes without, by vacuuming 1 m2 of carpet and by wiping 1 square foot of an adjacent wall. Felis domesticus allergen I (Fel d I) was detected in 30 of 31 settled dust samples (range, not detectable to 832,000 mU/gm; median, 10,250 mU/gm) and in 27 of 31 wall-wipe samples (range, not detectable to 113.7 mU per filter; median, 1.2 mU per filter). There was a significant correlation between Fel d I content in settled dust and wall-wipe samples (rs = 0.73; p less than 0.001). To assess the reproducibility of the wall-wipe method, multiple wipe samples were obtained from 20 homes, revealing a mean coefficient of variation of 110%. In contrast to Fel d I, although Dermatophagoides farinae allergen I was detected in 23 of 25 settled dust samples (range, not detectable to 11,888 ng/gm; median, 1178 ng/gm), it was detected in only four of 25 wall-wipe samples. We conclude that cat allergen, but not dust mite allergen, is widely distributed on wall surfaces and that wipe samples provide a simple and effective means of assessing household exposure to cat allergen.

Allergens↗
PubMed1996

The control of house dust mites in rugs through wet cleaning.

Nine rugs from the bedrooms of seven private homes were cut into strips. Half of the strips were wet-cleaned according to a commercial procedure, and the others were kept as controls. Subsequently the cleaned and noncleaned strips were stitched together again and returned to their respective bedrooms. After 0, 1, and 3 months, parts of the strips were taken to the laboratory for tests. The tests were designed to measure the suitability of the rugs as a habitat for house dust mites. To do this, a number of house dust mites were introduced into fragments of the rugs, and the number of survivors and offspring after 4 weeks was determined. Immediately after cleaning, the habitat was markedly less suitable than before. After 1 month, the habitat suitability was partly but not totally recovered. After 3 months, no effect of cleaning could be discerned.

Allergens↗
PubMed1996

Measurement of airborne mite allergen exposure in individual subjects.

To evaluate the extent of personal exposure to airborne mite allergens, subjects were asked to carry a personal air sampler when in their houses. The level of Der 1 allergen trapped by the sampler was measured with a highly sensitive immunoassay. There were great variations in airborne Der 1 exposure in each subject. When used bedding was replaced with new allergen-free bedding, we detected a decrease in the allergen level. The use of new bedding seems to be an effective measure for reducing airborne mite allergen exposure.

Air Pollutants↗
PubMed1997

Generation of anaphylatoxins through proteolytic processing of C3 and C5 by house dust mite protease.

BACKGROUND: The group 3 allergen of Dermatophagoides species (Der p 3 and Der f 3) has been identified as a 30 kd trypsin-like protease of the house dust mite. We previously showed that the 30 kd protease from Dermatophagoides farinae (Df-protease) could activate the bradykinin-generating cascade and exacerbate inflammatory reactions. OBJECTIVE: The purpose of this study was to determine whether Df-protease could enzymatically generate anaphylatoxins from complement components C3 and C5. METHODS: Df-protease was incubated with human serum C3 or C5 in a purified system, and the anaphylatoxin activity produced was assayed by measuring enhancement of vascular permeability and release of histamine from mast cells triggered by C3a and by assessing chemotaxis of polymorphonuclear cells caused by C5a. We also attempted to determine whether protease isolated from house dust could cause release of C5a from C5. RESULTS: Df-protease showed strong activation of C3 and C5, producing C3a and C5a by proteolytic cleavage of the complements. An appreciable amount of Df-protease was recovered in the house dust extract, and the house dust protease caused C5a release from C5. CONCLUSION: Df-protease activated the complement system to produce anaphylatoxins. Thus it is suggested that house dust mite proteases may contribute to the pathogenesis of allergic and inflammatory diseases caused by house dust allergens.

Air Pollution, Indoor↗
PubMed1999

Umbilical cord blood mononuclear cell proliferative response to house dust mite does not predict the development of allergic rhinitis and asthma.

BACKGROUND: Cord blood mononuclear cells (CBMNCs) have been found to proliferate when stimulated with food or inhalant allergens. The significance of this finding is not known. OBJECTIVES: We sought to determine the factors associated with proliferation of CBMNCs when stimulated with house dust mite (HDM) allergen and to determine whether proliferation of CBMNCs is associated with subsequent development of HDM sensitization and development of allergic rhinitis and asthma. METHODS: Cord blood was taken from infants at high risk for having asthma and allergic diseases who were recruited for a primary prevention study in which infants were randomized into the intervention or the control group. CBMNCs were stimulated with HDM allergen and PHA as a positive control. Infants were assessed at 12 and 24 months for health outcome. RESULTS: When stimulated with HDM allergen, 29.7% of infants had a stimulation index (SI) of 2 or greater. There were no differences in the levels of cord blood IgE and cotinine, maternal smoking, immediate skin test reactivity, maternal IgE, and maternal exposure to HDM allergen between those with an SI of 2 or greater and those with an SI of less than 2. Infants with an SI of less than 2 had a significantly higher proportion of mothers with a history of asthma. No differences in the incidence of "asthma" and rhinitis without cold at 12 months and cumulative prevalence at 24 months were seen between the 2 groups. None of the infants had skin test reactions to HDM allergen. CONCLUSION: The negative association between HDM allergen-induced proliferation of CBMNCs and maternal mite allergen exposure and health outcomes at 12 and 24 months raises the issue of the significance of CBMNC proliferation.

Allergens↗
PubMed1999

IL-12 affects Dermatophagoides farinae-induced IL-4 production by T cells from pediatric patients with mite-sensitive asthma.

BACKGROUND: IL-12 is a critical cytokine in the regulation of immune responses produced by phagocytic cells exposed to microorganism infection. OBJECTIVE: We sought to study the effect of low doses and high doses of IL-12 on TH1 versus TH2 cytokine expression to elucidate the etiology of mite antigen-sensitive bronchial asthma in infants. METHODS: We studied the effect of IL-12 on Dermatophagoides farinae (Df) antigen-induced IL-4 production and subsequent production of IgE by PBMCs from pediatric patients with asthma. RESULTS: Simultaneous addition of 1 to 10 ng/mL IL-12 to cultures enhanced Df-induced IL-4 production, although low doses (0.05 to 0.1 ng/mL) of IL-12 downregulated IL-4 production. Endogenous IL-12 is required for such production. These phenomena were not observed in Df-stimulated control PBMCs. In contrast, on stimulation with the same dose of Df, IFN-gamma production by patient PBMCs was enhanced in a dose-dependent fashion by addition of IL-12. Quantification analysis of RT-PCR-amplified DNA fragments by laser-induced fluorescence showed that a high dose of IL-12 augments mRNA expression for IL-4 protein synthesis, whereas a low dose of IL-12 inhibits IL-4 mRNA expression, and that the signal of mRNA for IFN-gamma protein synthesis was increased on Df stimulation in a dose-dependent fashion. Df-induced in vitro production of IgE and Df-specific IgE in serum from severe combined immunodeficient mice reconstituted with PBMCs were increased by treatment with high doses of IL-12, whereas low doses of IL-12 inhibited that production. The combined results indicate that at a low dose of IL-12, IL-4 and IFN-gamma production was regulated reciprocally; however, at high doses of IL-12, cells produced IL-4 and IFN-gamma simultaneously, and neither cytokine was regulated. CONCLUSION: Low-dose and high-dose IL-12 induce TH1 responses, and high-dose IL-12 induces both TH1 responses and TH2 or TH0 responses. Consequently, the IL-4 production may overcome TH1-type cell activation of IgE production in patients with mite-sensitive bronchial asthma.

Animals↗
PubMed1999

Evaluation of materials used for bedding encasement: effect of pore size in blocking cat and dust mite allergen.

BACKGROUND: Mattress and pillow encasings are recommended for patients allergic to dust mites. Many encasements block allergen and are vapor permeable but do not allow free passage of air through the material. Recently, breathable fabrics made from tightly woven synthetic fibers or nonwoven synthetics have been recommend as encasements. OBJECTIVE: The purpose of this study was to develop a method for testing encasement materials made of breathable fabrics. METHODS: Dust samples containing a known quantity of allergen (Der f 1, Der p 1, and Fel d 1) were pulled across a variety of fabrics using a modified dust trap. Airflow through the dust trap was controlled with a vacuum pump. Five minutes after dust was introduced, the pump was shut off. A filter located downstream of the fabric collected allergen passing through the fabric during the test and was assayed with ELISA for the relevant allergen. Fabrics to be tested were obtained from manufacturers and specialty catalogs. RESULTS: As the average pore size decreases, the airflow through a fabric becomes restricted, and the pressure differential created by the vacuum pump increases. Dust mite allergens (Der f 1 and Der p 1) were blocked below detectable limits by fabrics of less than 10 microm in pore size. Fabrics with an average pore size of 6 microm or less blocked cat allergen (Fel d 1). CONCLUSION: The method we developed provided a rigorous and reliable test for leakage of common indoor allergens through breathable barrier fabrics. Our results show that tightly woven fabrics and nonwoven synthetic fabrics can block common indoor allergens but still allow airflow.

Allergens↗
PubMed1998

Randomised controlled trial of local allergoid immunotherapy on allergic inflammation in mite-induced rhinoconjunctivitis.

BACKGROUND: Non-injective routes of immunotherapy are thought to be valuable therapeutic options for respiratory allergy. We investigated the clinical efficacy and the effects of sublingual/oral immunotherapy on conjunctival allergic inflammation in patients with mite-induced respiratory allergy. METHODS: We used a double-blind placebo-controlled design. 20 patients with mite-induced rhinoconjunctivitis (six of whom also had mild asthma) were randomly assigned sublingual/oral immunotherapy (n=10) or placebo (n=10) for 2 years. We assessed symptom score by diary cards and inflammatory-cell infiltrate, and expression of intercellular adhesion molecule 1 (ICAM-1) in the conjunctiva after specific allergen challenge at enrollment and after 12 and 24 months of treatment. FINDINGS: We found significantly lower symptom scores in the immunotherapy group than in the placebo group in most of the winter months (p=0.05). Compared with the placebo group, inflammatory-cell infiltration after conjunctival challenge, and ICAM-1 expression on conjunctival epithelium decreased significantly in the first year of treatment in the immunotherapy group (p=0.04 and p=0.02, respectively). These effects were also seen for the minimum persistent inflammation, in symptom-free patients exposed constantly to allergens (p=0.02). Serum concentrations of eosinophil cationic protein decreased significantly (p=0.04). Immunotherapy was well tolerated and compliance was good. INTERPRETATION: Our results suggest that this immunotherapy is clinically effective in rhinoconjunctivitis and that it decreases the immune-mediated inflammatory responses to the allergen.

Administration, Sublingual↗
PubMed1997

Determination of the N- and C-terminal sequences required to bind human IgE of the major house dust mite allergen Der f 2 and epitope mapping for monoclonal antibodies.

B cell epitopes of the major house dust mite allergen Der f 2 from Dermatophagoides farinae were analysed using deletion mutants of Der f 2 expressed as fusion proteins in Escherichia coli. The reactivities of these partial Der f 2 molecules to human anti-mite IgE antibodies in atopic patients and to murine anti-Der f2 monoclonal antibodies (mAbs) were examined by immunoblotting. A C-terminal deletion mutant of Der f 2, 1-123, had almost the same reactivity to human IgE as the whole Der f 2 (1-129) and an N-terminal deletion mutant of Der f 2 (25-129) still had weak reactivity. On the other hand, in two deleted Der f 2 molecules, 1-120 and 30-129, reactivity was lost in spite of long overlapping sequences. These results suggest that the human IgE antibodies to Der f 2 in atopic patient sera recognize the conformational structures dependent on the tertiary structure of Der f 2, including disulfide bond formations, rather than the contiguous sequences of amino acids. The sequences 1-24, 25-29 and 121-123 were revealed as the minimum N- and C- terminal amino acid sequences required for IgE binding. Contrastingly, all three murine mAbs bound to the smaller deletion mutants, 1-90 and 67-129, suggesting that the cores of the epitopes for these mAbs exist in the 24 amino acid sequence of Der f 2, 67-90 overlapping the sequential human IgE epitope on Der p 2, the equivalent allergen from Dermatophagoides pteronyssinus. These findings are important for the understanding of the antigenic structure of Der f 2 and for the manipulation of the allergen for immunotherapy.

Allergens↗
PubMed1987

Mites and related disease.

Parasitic mites cause a variety of dermatoses in domestic animals. The clinical signs, diagnosis, and treatment of canine and feline demodicosis, canine scabies, notoedric mange, cheyletiellosis, otodectic mange, and other mite infestations are discussed.

Animals↗
PubMedDate not supplied

Mite antigens enhance ICAM-1 and induce VCAM-1 expression on human umbilical vein endothelium.

Although sublingual allergen-specific immunotherapy has been proved to be effective in the treatment of allergic diseases, controversy surrounds the means by which such a local therapy can induce systemic immunological changes. Adhesion molecules are critical in the regulation of leukocyte traffic. It has been hypothesized that allergenic extract, administered locally, may induce an up-regulation of the mucosal vessel vascular adhesion molecules (CAMs) resulting in local recruitment of circulating inflammatory cells. In the present study we investigated whether the mite antigens, Der p1 and Der p2, can modulate CAM expression of human endothelial cells (HEC). To do this, slices of whole human umbilical cord vein underwent short-term (8 hours) cultures in the presence or absence of mite antigen (baseline, unstimulated controls). Cryostatic sections of the specimens were then evaluated immunohistochemically for expression of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) molecules. The results revealed that while Der p1 is capable of significantly up-regulating ICAM-1 and VCAM-1 on HEC, Der p2 antigen moderately up-regulates ICAM-1 expression but is ineffective in modulating VCAM-1. Although preliminary, these results clearly support the hypothesis that at least some of the effects of sublingual immunotherapy may derive from inflammatory cell recruitment at the site of allergen release.

Administration, Sublingual↗
PubMedDate not supplied

Health-economic analyses of subcutaneous specific immunotherapy for grass pollen and mite allergy.

OBJECTIVE: To investigate the health and monetary consequences of treating allergy with specific immunotherapy (SIT) compared with symptomatic treatment/standard care among patients with grass pollen or mite allergy. METHODS: We performed an economic analysis based on 253 grass- and/or mite allergic patients who started SIT from 1.1.1996 to 1.1.2002 at the Allergy Unit, Aarhus University Hospital and at a specialist practice in Aarhus. Relevant data were collected before, during and after SIT treatment from the national health service based on each patient's personal identification number and medical records and from a specifically designed questionnaire. A cost-benefit analysis including direct and indirect costs before, during and after SIT was performed. In addition direct costs were related to the clinical effect (improvement in well-being) in the form of a cost-effectiveness analysis. RESULTS: The direct cost per patient/year before SIT (equivalent to standard care) was DKK 2,580. The investment in SIT was DKK 27,545 (in present values) per patient over a 4-year period. After SIT the cost was reduced to DKK 1,072 per patient/year. In the long term, prospective introduction of SIT incurred additional present-value direct costs of DKK 13,676 per patient treated and DKK 2,784 per patient/year of improved well-being. However, when indirect costs were included in the economic evaluation SIT was shown to be net beneficial. CONCLUSION: This study reveals that SIT is associated with initial resource investments and subsequent resource savings in the long term compared with standard care. When all consequences are measured in monetary terms, and assuming that sick days are associated with a loss of productivity, this analysis suggests that SIT increases societal welfare. This conclusion also holds if there is no loss of productivity.

Absenteeism↗
PubMed2002

Oribatid mites as intermediate hosts of Thysanosoma actinioides (Cestoda: Anoplocephalidae): a preliminary study.

Thysanosoma actinioides Diesing, 1834 (Cestoda: Anoplocephalidae) parasitizes domestic and wild herbivores, and its life cycle has not yet been completely elucidated. The aim of this study was to analyze the role of oribatid mites as intermediate hosts of T. actinioides. The work was carried out at a Merino sheep breeding farm situated in the Pre-Cordillera region near Bariloche City, Río Negro Province, Argentina. The proglottids of T. actinioides were obtained from feces of infected sheep. In the laboratory, they were placed in the plastic wells with oribatid mites. The species of oribatids used in this experimental trial were Zygoribatula striassima Hammer, 1962 (Family Oribatulidae) and Oribatella spp. Banks, 1895 (Family Oribatellidae). Both species became infected with larval stages of T. actinioides. However, the infective cysticercoid stage did not develop.

Animals↗
PubMed2003

Sequence of a cDNA encoding acetylcholinesterase from susceptible and resistant two-spotted spider mite, Tetranychus urticae.

Acetylcholinesterase (AChE) from two-spotted spider mites, Tetranychus urticae was compared between an organophosphate susceptible (TKD) and a resistant (NCN) strain. The AChE of TKD had lower affinity to acetylthiocholine and propionylthiocholine than that of NCN, and the inhibition of AChE by DDVP, ambenonium, eserine and n-methyl-eserine showed that NCN was more insensitive than TKD. AChE cDNA sequence was determined, and the 687 amino acids of primary structure were deduced. There were six replacements of amino acid residues in TKD and two in NCN. #F331(439)C was the only substitution unique to NCN, however, this mutation existed homozygously in only two out of nine mites. This residue is one of the gorge lining components, and #F331(439)C might act an important role in the sensitivity of AChE to the inhibitors.

Acetylcholinesterase↗
PubMed2002

Two-spotted spider mite allergy: immunoglobulin E sensitization and characterization of allergenic components.

BACKGROUND AND OBJECTIVE: Previous investigations demonstrated that two-spotted spider mite (TSM) inhalation causes allergic asthma in agricultural workers. This work investigates whether TSM causes similar problems in the urban population. We determined the sensitization rate to TSM. We also identified immunoglobulin (Ig)E-binding components and evaluated their relationship with house-dust mite (HDM) allergens. METHODS: We carried out skin prick test (SPT) with TSM in 1,806 respiratory allergy patients over 1 year. TSM-IgE was detected by enzyme-linked immunoadsorbent assay (ELISA). TSM-sensitized patients were classified into two groups: patients who were skin test-positive to both TSM and HDM were included in group A and patients who were skin test-positive to TSM only were included in group B. ELISA inhibition test using sera from group A and B were conducted. IgE-immunoblotting was used to identify major allergens. These were purified by 2-dimensional electrophoresis and blotted onto polyvinylidene difluoride, and N-terminal sequences were identified. RESULTS: SPT (> or = 2+ of allergen/histamine) was positive in 358 (19.8%) patients. Twelve (6.6%) showed positive response to TSM only, and 54.5% had positive specific IgE. ELISA inhibition test using sera from two groups showed significant inhibition by TSM with minimal inhibition by HDM. Amino acid sequence of three major allergens was not homologous with any previously characterized allergens. CONCLUSION: IgE-sensitization rate to TSM was 19.8% in respiratory allergy patients. Eleven IgE-binding components and three major allergens were identified. The pIs and amino acid sequences of the major allergens were determined.

Allergens↗
PubMed2000

Local and systemic reactions during immunotherapy with adsorbed extracts of house dust mite in children.

BACKGROUND: We retrospectively evaluated the incidence of local and systemic reactions to injections of adsorbed extracts of house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) applied according to a conventional schedule in children. METHOD: Eighty-eight patients aged 6 to 15 years, suffering from allergic asthma or asthma together with rhinitis, at various stages of treatment with immunotherapy from January 1989 to November 1997 were included. RESULTS: Out of 5,760 injections, 5,542 (96.21%) were not associated with a reaction, 206 injections (3.57%) caused local reactions (144, <20 mm in diameter; 62, >20 mm), and systemic reactions were seen after 12 injections (0.2%). Twelve patients experienced 12 systemic reactions. Of these, 7 patients (58.3%) experienced no local reactions prior to a systemic reaction. Eleven males and one female had systemic reactions. Most of both local and systemic reactions occurred within less than 30 minutes after the injection. CONCLUSIONS: Our study supports the safety of immunotherapy with house dust mites in children. The majority of reactions were local. Although five of 12 patients who experienced systemic reactions had local reactions prior to a systemic reaction, in general the presence of local reactions was not helpful in predicting which patients would develop systemic reactions. Males and patients with asthma together with rhinitis appeared to be at greater risk for systemic reactions.

Allergens↗