Prevalence of sensitization to Blomia tropicalis among young adults in a temperate climate.

BACKGROUND: There are no previous population-based studies assessing the prevalence of Blomia tropicalis (BT). This investigation analyzes the prevalence of sensitization to BT and its contribution to asthma and related diseases among young adults in the Canary Islands. MATERIAL AND METHODS: From a random sample of 9506 adults, aged between 20 and 44, who had previously answered a short respiratory questionnaire, a further 20% random sample was drawn. All participants filled in an extensive questionnaire, and they underwent spirometry and bronchial hyperresponsiveness (BHR) test and skin testing to several allergens as well as the determination of total IgE and specific IgE. RESULTS: The prevalence of positive skin tests to BT was 13.8% (95% confidence interval [CI] 10.6-17.9%) and that of BT-specific IgE 17.9% (95% CI 14.2-24.5%). Sensitization to BT (positive skin tests or positive specific IgE) was 20.9% (95% CI 16.9-25.5%). Most of the subjects sensitized to BT were also sensitized to Dermatophagoides pteronissimus; however, only 7% displayed monosensitization to BT. Among subjects who exhibited BHR, sensitization to BT reached 46.7% (95% CI 32.7-60.9%), among those with asthma 50% (95% CI 26.8-73.2%), in subjects with rhinitis 37.2% (95% CI 28.1-47.6%), and in those suffering from dermatitis 25.9% (95% CI 18.7-34.5%). A strong association of BT sensitization with BHR and asthma before and after 15 years was found. CONCLUSION: The prevalence of sensitization to BT among young adults in the Canary Islands is high, and it displays a close relationship with allergic respiratory diseases and dermatitis.

Mite fauna and mite antigen detection in house dust found in residential areas in Los Baños, Laguna, Philippines.

Dust mites are a medically important group of animals commonly found in carpets and mattresses in houses. Antigens in their feces cause allergic reactions such as asthma and contact dermatitis. Dust samples were vacuum-collected in a special collecting bag from a one square meter area of living room floors of 100 randomly sampled houses in Los Baños, Laguna, Philippines for one minute. Chromato-immunoassay ELISA (Mitey Checker) was used to detect mite antigenicity. Twenty-three species of mites were identified belonging to 7 families. Of these, Blomia tropicalis (265 mites/g of dust in 87% of households) of Family Glycyphagidae and Dermatophagoides farinae (71 mites/g of dust in 58% of households) of Family Pyroglyphidae were the most prevalent and abundant species. Forty-eight percent of households were detected to have low levels of antigen (< or = 5 microg/m2). There was a weak linear relationship between mean total mite intensity and antigen level (r = 0.129). Mean Dermatophagoides intensity and antigen levels were also found to have a weak linear relationship. More mites were found in carpeted living rooms (822 mites/g) when compared to non-carpeted living rooms (645 mites/g). Different floor types did not show any difference in mean mite intensity. Likewise, mite intensity did not show correlation with household size.

Allergy to cockroaches: challenges in diagnosis.

BACKGROUND: Blattella germanica and Periplaneta americana are the most common domestic species of cockroaches, found all over the world under favorable conditions. Allergen sensitivity can be detected through in vivo tests, such as skin prick tests (SPT) for immediate hypersensitivity and in vitro techniques, represented mainly by the sIgE determination. Nevertheless, there is no gold standard for the detection of hypersensitivity to cockroaches. This study aims to evaluate the agreement between skin prick test to different cockroach allergenic extracts with serum specific IgE determination in the diagnosis of cockroach allergy in asthmatic and non-asthmatic children. METHODS: A case-control study involving 74 asthmatic and 42 non-asthmatic children aged between 6 and 14 years was conducted in Recife, Brazil. All individuals were submitted to a skin prick test (SPT) with Dermatophagoides pteronyssinus, D. farinae, Blomia tropicalis (IPI-ASAC) and three different commercial cockroach extracts (Greer, Hollister-Stier, and IPI-ASAC Brasil) of B. germanica and P. americana, and to the quantification of total serum IgE and specific serum IgE to B. germanica and P. americana. RESULTS: The mean diameter of induced papule was considerably greater among the asthmatic patients when compared to non-asthmatic controls, regardless of the species or type of cockroach extract. The correlations between the various types of utilized extracts for the two species studied were not sufficiently strong. Hollister-Stier extract was the most sensible extract among asthmatics in this study for both B. germanica (54.1% [N = 40]) and P. americana (59.5% [N = 44]). A satisfactory correlation was found between the serum levels of specific IgE and total IgE for both species of cockroaches. The correlation of specific IgE serum level from each species with its respective SPT was not considered satisfactory. CONCLUSIONS: The weak correlation between the different extracts clearly indicates a need for standardization of the extracts for SPT for cockroach allergy diagnosis. According to this study, only a patient with high specific IgE serum levels and a positive SPT to a cockroach species should be truly classified as hypersensitive to B. germanica and/or P. americana.

Determination of CD4+ and CD8+ T cells in the peripheral blood of dogs with demodicosis.

The aim of this study was to evaluate the CD4+/CD8+ ratio in peripheral blood of dogs with localized and generalized demodicosis. Sixteen dogs were examined, 8 with localized and 8 with generalized demodicosis, while 8 healthy dogs were used as controls. Peripheral blood was obtained and CD4+ and CD8+ T cells were determined by flow cytometry. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were found in dogs with generalized demodicosis compared to dogs with localized demodicosis and healthy controls. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were also found in dogs with localized demodicosis compared to healthy controls. The CD4+/CD8+ ratio was also found to be significantly lower in dogs with generalized demodicosis in comparison with dogs with localized demodicosis and healthy controls. It is concluded that significant alteration in the CD4+/CD8+ ratio may be implicated in the pathogenesis of generalized canine demodicosis.

Immune responses of the domestic fowl to Dermanyssus gallinae under laboratory conditions.

There appear to be few reports in the literature regarding the host-poultry red mite (Dermanyssus gallinae) immunological relationship, despite the negative impact D. gallinae can have on both bird welfare and egg production, as well as its potential to act as a reservoir of zoonotic infections. The current study investigated the effect of either continuous infestation (CI) for 22 days or repeated infestation (RI) for four 24-h periods 7 days apart with D. gallinae on humoral immunity (IgM and IgY) and Th1/Th2 cytokine mRNA expression in peripheral blood mononuclear cells (PBMC) compared to non-infested controls. Serum IgY levels and IgM concentration were significantly higher in CI than RI and control birds although Th1 and Th2 mRNA expression in PBMC did not differ significantly between groups. D. gallinae appeared to modify reproductive behaviour and progeny survival following successive feeding events. In the RI group, the proportion of eggs/mite was significantly higher (P < 0.05) after first infestation than later infestations while larval/nymphal mortality was significantly higher (P < 0.05) after the first two infestations than later infestations. These data suggest that D. gallinae might adopt a feeding strategy of minimal host interference while D. gallinae could determine host immune status via nymphal/larval survival rates. Further research is required to better understand the host immunomodulation or avoidance strategy of D. gallinae as well as whether the mite is able to determine host immunocompetence perhaps using progeny survival.

Allergenic cross-reactivity between Blomia tropicalis and Blomia kulagini (Acari: Echymiopodidae) extracts from optimized mite cultures.

BACKGROUND: At present, data about the cross-reactivity of Blomia spp. comes from studies made among different genera of mites, and no results have been published involving different species of the genus Blomia. OBJECTIVE: The aim of this study was to find out the level of cross-reactivity between the two main species of Blomia causing allergy, and its implication in the diagnosis of Blomia sensitization. METHODS: Using extracts from optimal growth phases of Blomia kulagini (Zakhvatkin, 1936) and Blomia tropicalis (van Bronswijk, Cock and Oshima, 1973) as allergenic material, the allergenic cross-reactivity between both house dust mites was evaluated by means of cutaneous tests, specific IgE values, ImmunoCAP-inhibition and SDS-PAGE-IgE-immunoblotting-inhibition. RESULTS: The results demonstrated that IgE-binding components belonging to both species are very similar from the immunological point of view, showing high correlations between both species when using cutaneous tests (R2=0.915) or specific IgE (R2=0.980). ImmunoCAP-inhibition and SDS-PAGE-IgE-Immunoblotting-inhibition probed with human sera, showed a total inhibition of specific IgE reactions by the heterologous antigens. CONCLUSION: The results obtained strongly suggest the great resemblance between the allergenic composition of both species.

First report on sensitization to allergens of a house dust mite, Suidasia pontifica (Acari: Saproglyphidae).

A species of house dust mite, Suidasia pontifica, was recently shown to produce allergens affecting man. The species may be as important as other allergen producing mite in sensitization and causing allergic symptoms in Malaysians. Surveys conducted demonstrated that 80% of the houses surveyed were positive for this mite with densities ranged from 2 to 50 mites per gram of dust. Colonies of the species has been successfully established and materials from those colonies have been used to produce extracts for studies on sensitization to the mites. A total of 85 suspected allergic rhinitis patients were tested and 74.1% demonstrated positive reactions. Extract of this mite should be considered for routine diagnostic testing and possible immunotherapy.

[Habitat of the allergic child: theory and practice]. / Habitat de l'enfant allergique: théorie et pratique.

Control of the asthmatic child's environment forms an integral part of therapeutic care. This requires knowing what the main allergens in the child's habitat are and how they arise: eg, acarids, animal teguments, insects and fungi. The overall measures for reducing them chiefly entail controlling humidity: regular airing, or even ventilation, and eliminating sources of humidity can be recommended. Control of acarids will require modifying furnishings (no mats or carpeting, non hangings or heavy curtains, a slatted not interior spring bed base). Acarid-repellent loose covers seem to be more effective than acaricides, which give conflicting results. Physical processes, although necessary, are seldom sufficient. Animals should be evicted. If this is impossible, certain measures have proved effective, however. Insects and moulds are controlled by specific sanitary measures. A practical approach is proposed that takes into account both theoretical demands and everyday realities.

[Allergens causing respiratory allergy: the aeroallergens]. / Allergènes responsables d'allergie respiratoire: les pneumallergènes.

Aeroallergens play a major role in the pathogenesis of allergic diseases, particularly asthma and rhinitis. Indoor allergens, including house dust mites, domestic pets, cockroaches, and molds are of particular importance. Pollens are also recognized as a major source of allergens. The role of these different allergens varies with environment conditions, such as climatic factors, and degree of exposure. Knowledge about allergens has progressed, especially with recent molecular biology studies. Structure and function have been identified. These studies have provided explanations about the relationship between allergic sensitization, allergen exposure, and disease activity, about clinical observations such as allergic cross reactions, and improvement in the production of allergenic extracts (necessary to diagnosis and immunotherapy). Environmental control measures are of particular importance in the prevention and management of allergic diseases.

[Circannual rhythm of the risk of IgE-dependent sensitization to acari depending on the birth date. Interpretation and practical consequences in prevention]. / Rythme circannuel du risque de sensibilisation IgE-dépendante aux acariens en fonction de la date de naissance. Interprétation et conséquences pratiques en prévention.

The role of allergenic environment during the first weeks of life for the future development of IgE-dependent allergy is well documented for cyclic allergens. That is less evident for permanent antigens as house dust mites. The aim of this work was to find a possible relation between the birth date and house dust mite hypersensitivity to have a better prevention. The result of Rast d1 which show an IgE-dependent allergy to Dermatophagoides pteronyssinus was correlated to the month of birth of 5, 747 children and adolescents with a suspected allergic respiratory disease. Possible bias induced by sex and personal/family history were mathematically corrected. A correlation curve between the month of birth and the frequency of positive Rast d1 was deduced. There is a circannual rhythm risk for house dust mite allergy according to the month of birth. It draw a sinusoid curve with a peak at 104 percent in october and a minimum at 96 percent in april. These data were discussed. The minimum of risk was possibly due to better early ecologic way of life for infants born during the spring. Preventive methods were available against house dust mites. They could be organized for infants. We hope that more pediatricians were concerned by primary prevention of house dust mite allergy.

[Seasonal changes in specific IgE: the acarid Dermatophagoides pteronyssinus]. / Variations saisonnières des IgE spécifiques: acariens Dermatophagoïdes pteronyssinus (D.P.).

The authors have studied monthly the titres of specific IgE to Dermatophagoides pteronyssinus, by Phadebas RAST, in 8435 measurements, spread over 4 years. Significant seasonal and monthly variations were seen every year with a maximum level in the autumn or the beginning of winter, with a second peak at the end of winter in 3 years of the 4. There was no close superposition of pattern form one year to another. The domestic relative humidity had a significant effect on the seasonal variation with a mean shift of 2 months that could be explained by the length of the biological cycle of the mites. These data compare with those of the literature (sampling of mites in bedding, longitudinal studies...).

[Allergy to Thyrophagus putrescentiae and Lepidoglyphus destructor in a population of young asthmatic adults]. / L'allergie à Thyrophagus putrescentiae et à Lepidoglyphus destructordans une population d'adultes jeunes asthmatiques.

In the present work a study has been made of the prevalence of allergy to two storage mites, Tyrophagus putrescentiae and Lepidoglyphus destructor in a population of 105 young adults in the east of France. Combination of skin tests and specific IgE measurements shows that 43.10% of the subjects were sensitive to Tyrophagus and 44.95% to Lepidoglyphus. Interpretation of skin tests remains uncertain, particularly concerning the source of the allergen used and it is most often also necessary to measure the specific serum IgE. As in many studies, most sensitization was found amongst farmers. In contrast, no difference was seen between rural and city dwellers, subjects who were in contact with small animals and those in contact with food for livestock if they were not farmers, not between declared asthmatics who lived in a humid place and those who lived in an environment that was drier. Certainly these mites appeared in the present study to be much more ubiquitous than supposed previously and the fact that they seemed to be carriers of allergens and antigens that were different from those of Dermatophagoides raises the question as to whether the need for hyposensitization treatment for them has been under-estimated.

[RAST and acari in stored goods]. / RAST et acariens des denrées entreposées.

During a multicentre trial, responses of serum from 60 asthmatic children with allergy to the mite Dermatophagoides pteronyssinus (D1) were compared to D. farinae (D2) and 4 storage mites. The known cross reaction between D1 and D2 was confirmed but no such reaction was found between D1 and/or D2 and the storage mites. Because the important cross reactivity between storage mites, the choice of the allergen will depend on the historical and epidemiological data of the disease.

[Bacterial endotoxins: a pathogenic factor in asthma?]. / Les endotoxines bactériennes: un facteur pathogène de l'asthme?

Though the house dust mite allergen is considered as one of the most important factors in perennial asthma, several observations suggest that it could be but one of several factors leading to asthma. Exposure to bacterial endotoxins has been associated with some occupational chronic obstructive bronchial diseases. In the present work, endotoxins were measured in the house dust, and observations of the skin and bronchial challenge tests as well epidemiological studies suggest that they play a role in asthma.

[Effect of Lep d2 from Lepidoglyphus destructor as a vaccine for specific immunotherapy in murine with asthma].

OBJECTIVE: To assess the effect of Lep d2 from Lepidoglyphus destructor as a vaccine for specific immunotherapy on murine model of asthma. METHODS: Thirty BALB/c mice (SPF) were randomly categorized into a PBS group, an asthma group, and a Lep d2 SIT group. The mice in the asthma group and Lep d2 SIT group were sensitized by intraperitoneal injection with extracts of dust mites on Days 0, 7th, and 14th, while those in the PBS group were injected with PBS. From the 21st day, the asthma group and Lep d2 SIT group exposed to the extracts of dust mites were stimulated by aerosol inhalation for 7 successive days. During the period of the 25th-27th Day, the mice in Lep d2 SIT group were injected intraperitoneally with Lep d2 allergen for SIT 30 min before nasal inhalation, whereas the PBS group and asthma group were treated with only PBS. Twenty-four hours after the final inhalation, all the mice were sacrificed, the bronchoalveolar lavage fluids (BALFs) were collected. The levels of IFN-γ, IL-5 and IL-13 in the BALF and the supernatant of splenocyte culture solution (SSCS) as well as the levels of specific IgE (sIgE) and sIgG2a in the sera were detected by ELISA. The lung tissues of the mice in the above 3 groups were stained by haematoxylin and eosin (H&E) and observed by a microscope. RESULTS: The symptoms of acute asthma attack were observed in the mice of the asthma group and Lep d2 group, but not in the PBS group. The allergic inflammation changes in lung in the Lep d2 SIT group were significantly alleviated compared with those in the asthma group. The concentrations of IFN-γ in BALFs and SSCS of the mice in the Lep d2 SIT group were significantly higher than those in the asthma group (both P < 0.01), while the levels of IL-5 and IL-13 in the former group were significantly lower than those in the latter group (all P < 0.01). Meanwhile, the level of sIgE of mice in the Lep d2 SIT group was significantly lower than those in the asthma group (P < 0.01), while the level of sIgG2a of mice in the former group was higher than those in the latter group (P < 0.01). CONCLUSION: Lep d2 allergen as a vaccine can alleviate the allergic symptoms in the lung of mice effectively after allergen specific immunotherapy.

The impact of pulmonary tuberculosis treatment on the prevalence of allergic rhinitis.

Atopy is a syndrome characterized by immediate hypersensitivity reactions to common environmental antigens. The "hygiene hypothesis" stipulates that childhood infections are associated with a lower risk of allergies. Not much has been published about the effects that the treatment of pulmonary tuberculosis (TB) has on allergies, specifically allergic rhinitis. We conducted a study to investigate the prevalence of allergic rhinitis in patients with pulmonary TB before and after treatment of their TB. Our initial study group was made up of 121 patients with confirmed pulmonary TB who were followed up by questionnaire. In addition to demographic data, they provided information about their personal and family history of atopy and their current status with regard to allergic rhinitis. After providing informed consent, all patients underwent skin-prick testing with Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis allergens before and after TB treatment. Stool samples were obtained to identify patients with worm infestation, and they were excluded from the study. In all, 94 patients completed treatment and follow-up, and their data were included in the final analysis. Of this group, 31 patients (33.0%) exhibited symptoms of allergic rhinitis prior to TB treatment, and 26 (27.7%) had a positive skin-prick test. Following treatment, only 12 patients (12.8%) reported allergic rhinitis symptoms (p = 0.004), but there was no significant reduction in the number of patients with a positive skin-prick test (n = 20 [21.3%]; p = 0.555). We conclude that the treatment of pulmonary TB results in significant relief of atopy, particularly allergic rhinitis symptoms.

Antigenic profile of Blomia tropicalis, Aleuroglyphus ovatus and Glycycometus malaysiensis.

House dust mites and storage mites are well-known causes for allergenic diseases. The aim of this study was to investigate the immunogenic sites of Blomia tropicalis, Aleurogyphus ovatus and Glycycometus malaysiensis. The mites were maintained in a culture medium at 25ºC and 75% relative humidity. Mites were harvested either with heat escape or floatation method, purified, homogenized, quantified and used for the production of polyclonal antibody and immunostaining. For each species of mites, five male mice and five male rats were randomly selected and immunized intraperitoneally with respective crude mite extract at two-weekly intervals. Blomia tropicalis, A. ovatus or G. malaysiensis whole mites and paraffin-embedded mite sections were immunostained with the respective polyclonal antibody. The faecal pellets of mites were intensely stained for all the three species in the present study. The legs of sectioned A. ovatus were not immunogenic as compared with those of G. malaysiensis and B. tropicalis. The outer layer (cuticle) of whole mites and the eggs for these species were very immunogenic. Hence, the polyclonal antibodies obtained in this study may serve as potential tools in detecting the eggs and immature mites in environmental samples. Future studies should focus on the antigenic components of eggs since they were relatively abundant in dust and highly antigenic as seen in the present study.