Pancake syndrome (oral mite anaphylaxis)

Oral mite anaphylaxis is a new syndrome characterized by severe allergic manifestations occurring in atopic patients shortly after the intake of foods made with mite-contaminated wheat flour. This clinical entity, observed more frequently in tropical/subtropical environments, is more often triggered by pancakes and for that reason it has been designated "pancake syndrome". Because cooked foods are able to induce the symptoms, it has been proposed that thermoresistant allergens are involved in its production. A novel variety of this syndrome occurs during physical exercise and therefore has been named dust mite ingestion-associated exercise-induced anaphylaxis. To prevent mite proliferation and the production of anaphylaxis, it has been recommended that wheat flour be stored at low temperatures in the refrigerator.

Gregarines in Dermatophagoides spp. (Acari: Pyroglyphidae): light microscopy observation

Recently there has been an increasing interest in studying arthropods that live close to humans, such as cockroaches and mites, for their potential as vectors. Gregarines observed under light microscopy in intestinal extracts of house dust mites (Dermatophagoides spp.) are described for the first time in scientific literature.

Allergic sensitization to domestic mites in Corpus Christi, Texas

Corpus Christi, TX, is a Gulf Coast city with high humidity levels year-round. There is little available data on mite species in mattress dust, allergen levels, and sensitization to different mite species in allergic patients. This study was designed to determine skin sensitization and specific serum IgE to Dermatophagoides spp. and Blomia tropicalis in patients attending an allergy clinic and to explore the mite fauna and allergen content of their mattresses. Skin-prick tests to Dermatophagoides spp. and B. tropicalis along with mite-specific IgE in the serum by enzyme-linked immunosorbent assay (ELISA) and ImmunoCAP tests were performed in allergic patients attending an outpatient allergy clinic in Corpus Christi, TX. Mite species and allergen levels were determined in mattress dust. Forty-five consecutive patients were evaluated; 10 patients had positive skin tests to Dermatophagoides pteronyssinus and B. tropicalis, 32 patients reacted only to D. pteronyssinus, and 3 patients reacted exclusively to B. tropicalis. Increased titers of D. pteronyssinus- and D. farinae-specific IgE were present and B. tropicalis-specific IgE titers were lower. Significant amounts of mites were observed in 79.5% of dust samples, with a predominance of D. pteronyssinus and D. farinae. Other mite species, such as B. tropicalis, Euroglyphus maynei, Tarsonemus spp., Tyrophagus putrescientiae, Cheyletus spp., and Oribatidae were also observed. Greater levels of Der p and Der f 1 than of Blo t 5 were present in the mattresses. D. pteronyssinus and D. farinae are the prevalent mite species in houses of allergic patients from Corpus Christi, TX. Other mite species are also found.

Detection of allergen composition and in vivo immunogenicity of depigmented allergoids of Betula alba

BACKGROUND

Chemical modification of allergen vaccines to reduce IgE binding improves safety while maintaining clinical efficacy. However, this also complicates the characterization of allergoids using techniques as for native allergen extracts.

OBJECTIVES

The objective of this study was to analyse the molecular size of Betula alba depigmented allergoids, conservation of major allergens in the allergoids and in vivo antibody response to immunization.

METHODS

The molecular size of depigmented allergoids was evaluated by high performance-size exclusion chromatography and light scattering techniques. Protein composition was compared with native extracts by capillary liquid chromatography-tandem mass spectrometry based peptide mapping. Rabbits were immunized with depigmented allergoid of Betula pollen adsorbed onto aluminium hydroxide (Depigoid). IgG antibodies against individual allergens were determined by ELISA and immunoblot.

RESULTS

Depigmented allergoids contained a range of high molecular weight particles, approximately 60% of which had a molecular weight of 1-3 MDa. Peptide sequencing confirmed the preservation of five isoforms of Bet v 1, as well as Bet v 2, Bet v 6 and Bet v 7. Sera from immunized rabbits showed high levels of specific IgG to rBet v 1.0101 and rBet v 2.

CONCLUSIONS

The mean protein content was 544+/-106 microg per mg of freeze-dried material for depigmented allergoids and 434+/-71 for native extracts. They retain the capacity to induce specific IgG antibodies against individual allergens present in the native extract. These findings confirm the immunogenicity of depigmented allergoids and may explain why patients treated with these vaccines are protected against the native allergens. Analysis of molecular size and allergen content may be useful techniques for characterization and standardization of allergoid products.

Enzymatic activity of Dermatophagoides pteronyssinus extracts after acidic treatment

BACKGROUND

Mite extracts contain potent enzymes. These enzymes, especially Der p 1, may affect the bronchial homeostasis and the amplification of the allergic response. The objectives of this study were to determine how depigmentation affects the enzymatic activity of allergen extracts of Dermatophagoides pteronyssinus and to verify if these depigmented extracts retain their in vitro allergenic properties.

METHODS

Four native extracts were manufactured from 4 different batches of raw material of D. pteronyssinus. Once extracted, native extracts were reconstituted and modified by adding increasing quantities of 2 M HCl to the solution and dialyzed against double-distilled water. The enzymatic activity of these 8 extracts (4 native and 4 depigmented) was evaluated using in vitro methods. The allergenic potency was evaluated by human specific IgE and IgG ELISA inhibition experiments. The major allergen content (Der p 1 and Der p 2) was measured with monoclonal antibodies.

RESULTS

Protease, phosphatase, lipase and glycosidase activity was detected in native extracts. After depigmentation, all the enzymatic activities showed a significant decrease. SDS-PAGE reveals the same protein profile in both types of extracts. The results of ELISA inhibition confirmed that depigmented extracts preserved their antigenic and allergenic capacity. Der p 2 levels increased in depigmented extracts, while the detection capacity of Der p 1 decreased.

CONCLUSIONS

The depigmentation process significantly reduced the enzymatic activity of these mite extracts, while preserving their allergenicity and antigenicity. No significant differences were observed in the antigenic profile of native and depigmented extracts.

Enzymatic Activity in Body and Fecal Extracts of the Storage Mite Chortoglyphus arcuatus

BACKGROUND

Chortoglyphus arcuatus has been described in many countries. Many allergens are potent enzymes, which may promote a Th2 immune response. The aim of this study was to evaluate the enzymatic activity of body and fecal extracts of C. arcuatus.

MATERIAL AND METHODS

Feces and bodies of full-grown C. arcuatus cultures were separated by sieving, extracted in PBS, dialyzed and lyophilized. The antigenic profile of both extracts was determined by SDS-PAGE. Immunoblot experiments were conducted using a pool of sera from allergic individuals residing in Galicia, a region of Spain, where this species is abundant. The enzymatic activity of the extracts was evaluated by the zymogram technique. Serine and cysteine protease activity was measured using in vitro methods. The API Zym system was used to determine the enzymatic properties of the extracts.

RESULTS

The antigenic profile showed that the body extract contained more and better defined bands than the fecal extract. Allergens were detected in both extracts in a molecular weight range between 14 and 100 kDa. Gelatinolytic gels confirmed that fecal extracts contain more hydrolytic enzymatic activity than body extracts. Serine protease activity in fecal extracts was higher than in body extracts (5.98 vs. 2.701 IU of trypsin/mg of freeze-dried material). No cysteine protease activity was detected.

CONCLUSION

C. arcuatus extracts contain several allergens and proteins with high enzymatic activity, especially in the feces. Some of these allergens may be enzymes. Fecal extracts have more enzymatic activity than body extracts.

Mite immunotherapy

Dermatophagoides pteronyssinus and D. farinae are the most common house dust mites and are among the most common sources of indoor allergens worldwide. These species are very common in humid regions, where most allergic individuals are sensitized to house dust mites. Specific immunotherapy with mite extracts has demonstrated clinical benefits in several double-blind, placebo-controlled trials that are included in recent reviews of subcutaneous immunotherapy, including pediatric and adult patients with rhinoconjunctivitis and or asthma. Most successful studies of mite immunotherapy have used native allergen extracts adsorbed onto aluminum hydroxide, or chemically modified mite-allergen extracts. Several studies have also shown efficacy using sublingual immunotherapy in pediatric and adult patients with asthma and/or rhinitis. Additionally, the efficacy of subcutaneous immunotherapy has been demonstrated in patients with atopic dermatitis, although more double-blind, placebo-controlled studies are needed. Based on several studies, it cannot be concluded that mite immunotherapy is more dangerous or safer than immunotherapy with grasses, epithelia, or animal epithelia. Because the delivery of high doses of allergen carries with it the risk for immunoglobulin E (IgE)-mediated events, several methods have been developed to reduce specific IgE binding to mite-allergen extracts. An important challenge for future mite immunotherapy modalities is the delivery of relatively high doses without a significant risk for severe reactions.

Sensitization and exposure to house dust and storage mites in high-altitude areas of ecuador

BACKGROUND

Few studies have addressed exposure and sensitization to mite allergens in Andean countries.

OBJECTIVES

To identify the main mite species in 3 locations at different altitudes in Ecuador and to verify skin test reactivity to various mite species in allergic individuals in Quito, Ecuador.

METHODS

Mattress dust samples were collected in Quito (2,800 m above sea level), Cuenca (2,500 m above sea level), and Guayaquil (sea level). Mite species present in the samples were isolated, identified, and counted. Der p 1 and Der f 1 levels were measured using monoclonal antibody-based enzyme immunoassays. Four hundred thirty-five patients in Quito diagnosed as having allergic rhinitis or asthma underwent skin testing with commercial extracts of Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Tyrophagus putrescentiae, and Lepidoglyphus destructor. In addition, Glycyphagus domesticus, Acarus siro, and Aleuroglyphus ovatus were tested in 362, 262, and 279 patients, respectively.

RESULTS

Twenty-one mite species were identified. Large populations of mites were detected above 2,500 m of altitude. All the dust samples contained detectable levels of Der p 1 or Der f 1. Positive skin prick test reactions to D. pteronyssinus, D. farinae, B. tropicalis, L. destructor, T. putrescentiae, A. ovatus, A. siro, and G. domesticus were obtained in 60.9%, 56.8%, 17.0%, 19.3%, 10.6%, 15.8%, 8.8%, and 11.0% of the patients, respectively.

CONCLUSIONS

Most analyzed mattresses contained several species of mites. Mite allergen levels were high. This study confirms the importance of house dust and storage mite allergens in Ecuador in areas above 2,500 m of altitude, where humidity remains high year round.

House dust mite species and allergen levels in Galicia, Spain: a cross-sectional, multicenter, comparative study

BACKGROUND AND OBJECTIVES

Mites are important sources of allergens in Galicia, Spain. The objective of this study were to identify the main mite species and to determine allergen levels in mattresses from different locations in Galicia.

MATERIAL AND METHODS

Dust samples were collected with a portable vacuum cleaner for 2 minutes from 2 m2 of the surface of the mattress used by mite allergic patients and controls. After collection, samples were immediatel frozen. Mite species were collected, identified, and counted, and the results expressed as mites per gram of dust. Mite allergen levels (Der p 1 and Der f 1) were measured using monoclonal antibodies. All individuals answered a questionnaire about the characteristics of their homes.

RESULTS

A total of 332 dust samples were collected (112 from mite allergic patients and 220 from controls). Thirty-two species were identified. The mean age +/-SD of all the participants was 32.4 +/- 20.8 years and of the mattresses 7.6 +/- 5.9 years. The geometric mean of the total mite counts was 910.2 mites per gram (896.2 mites per gram in the mattresses of mite allergic patients and 917.3 in the mattresses of control subjects; P > .05). The main species was Dermatophagoides pteronyssinus, which was present in 97.6% of the samples (geometric mean, 584.7 mites per gram). The geometric mean level of Der p 1 was 13.1 microg/g of dust: 11.9 in the mattresses of mite allergic patients and 13.8 in the mattresses of control subjects. The geometric mean level of Der f1 was 1.1 microg/g: 1.5 in the mattresses of mite allergic patients and 0.8 in the mattresses of control subjects. Environmental risk factors associated with high mite counts included obvious signs of humidity in the bedroom and the age of the mattress.

CONCLUSIONS

The mite fauna in Galicia is comprised of many species, several of which are known to be of allergologic importance. The total population is exposed to very high levels of mite allergens.