Comparison of Allergenic Properties among Commercially Available House Dust Mite Allergen Extracts in Korea

Precise allergy diagnosis and effective allergen specific immunotherapy are largely dependent on the quality of allergen extract. A new extract of Dermatophagoides farinae was commercially developed by Prolagen. The allergenic properties of the new extract were compared with those of other commercial products. The allergenic properties of the new extract were compared according to protein concentration, protein profiles, major allergen (Der f 1) contents, and allergenic potency to those for three commercially available extracts imported in Korea (Jubilant HollisterStier Allergy, Lofarma S.p.A., and Stallergenes Greer). Protein concentrations varied up to 2.62-fold (0.404 to 1.057 mg/mL), and Der f 1 contents varied up to 11.3-fold (3.597 to 40.688 μg/mL). Protein profiles of the extracts showed no major discrepancies, although there were some differences in SDS-PAGE band intensities, reflecting protein concentrations. Allergen potency ranged from 37038 to 60491 PAU/mL. The Prolagen product was highest in terms of protein concentration and allergen potency. The Lofarma product displayed Der f 1 content similar to that in Prolagen (19.4 μg/mg vs. 19.3 μg/mg). Endotoxin levels varied 8.9-fold (1020 to 8985 EU/mL). The newly developed house dust mite extract showed equal or better allergenic properties than available commercial extracts. This new product may be useful for better diagnostics and allergen-specific immunotherapeutics.

Stability of extracts from pollens of allergenic importance in Korea

Background/Aims@#Accurate diagnosis and the effects of allergen-specific immunotherapy for pollinosis are greatly dependent on the potency and stability of the extract. This study aimed to examine factors, such as temperature and storage buffer composition, that affect the stability of allergen extracts from pollens of allergenic importance in Korea. @*Methods@#We prepared four pollen allergen extracts from ragweed, mugwort, Japanese hop, and sawtooth oak, which are the most important causes of seasonal rhinitis in Korea. Changes of protein and major allergen concentration were measured over 1 year by Bradford assay, two-site enzyme-linked immunosorbent assay, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis after reconstitution of the lyophilized allergen extract in various buffers and stored at room temperature (RT, 18°C to 26°C) or refrigerated (4°C). @*Results@#More than 90% of the original protein concentration in all four extracts examined was detected over 1 year when 50% glycerol was added and refrigerated, whereas 57.9% to 94.5% remained in the extracts at RT. The addition of 50% glycerol to the storage buffer was found to prevent protein degradation at RT. Amb a 1, a major allergen of ragweed, was almost completely degraded in 9 weeks at RT when reconstituted in a buffer without 50% glycerol. However, 55.6% to 92.8% of Amb a 1 content was detected after 1 year of incubation at 4°C in all buffer conditions except 0.3% phenol. @*Conclusions@#Addition of 50% glycerol as well as refrigeration was found to be important in increasing the shelf-life of allergen extracts from pollens of allergenic importance.

Survey of IgE Reactivity to Nonbiting Midges in Korea and Identification of IgE-Binding Protein

PURPOSE: Chironomids (nonbiting midges) are widely and abundantly distributed near ponds, rivers, and artificially dammed pools used for irrigation. Chironomids contain allergens and cause airway allergy in humans. In this study, we aimed to examine the allergic potential of chironomids in inhabitants living near artificially dammed pools. METHODS: We examined immunoglobulin E (IgE) reactivity to chironomid extracts in the sera of residents living around installed dams and assessed the correlations of IgE responses between chironomids (Chironomus flaviplumus, Chironomus kiiensis, Cricotopus bicinctus) and house dust mites (Dermatophagoides farinae). In addition, we identified potential IgE binding proteins specific for adult C. bicinctus, a popular species in Korea. Specific IgE antibodies in sera collected from the participants against the extracts were tested using enzyme-linked immunosorbent assay (ELISA). RESULTS: The average IgE-positive rates were 10.4%, 8.1%, and 8.2% in C. bicinctus, C. flaviplumus, and C. kiiensis, respectively. The IgE-positive rate and IgE titer of C. bicinctus antigen were higher in residents living around installed dams than in those who lived other places (P = 0.013). Western blotting using sera having high IgE titers to C. bicinctus in ELISA showed the presence of a protein of approximately 42 kDa that was homologous to the actin protein isoform in C. bicinctus extracts as demonstrated using mass spectrometry. CONCLUSIONS: Our results showed that people living near installed dams were more sensitized to C. bicinctus and that the 42 kDa IgE-binding protein could be useful for further studies on chironomid allergic disease and clinical applications.

Allergen standardization

Allergen immunotherapy (AIT) and diagnostic tests are based on well qualified allergen extracts, which are derived from biologic organisms. The allergenicity of the extracts is markedly affected by the climate, soil, year of production, storage methods, and manufacturing processes. Thus, standardization is a crucial process to guarantee the clinical efficacy and safety of the treatment and diagnostic reagents in allergic diseases. There are 2 different standardization processes, one is In vivo and the other is in vitro standardization. In vivo standardization is done by skin prick or intradermal tests. For in vitro standardization, measurements of weight/volume and protein nitrogen units have been widely used since the early period of AIT. In the 1970s, immunological methods such as radial immunodiffusion, enzyme-linked immunosorbent assay (ELISA) inhibition test and basophil activation test were developed. Allergen potency measured by ELISA inhibition test reflects the potency measured by skin tests and has been widely used for quality control of batch-to-batch variation. Recently, standardizations focused on the major allergen content of extracts have developed. Standardization for major allergens requires reliable reference materials (RMs) made of recombinant allergens and 2-site ELISA kits. However, only a few reliable RM and 2-site ELISA kits are available. For the standardization process, allergen RMs are essential. The Center for Biologics Evaluation and Research of the U.S. Food and Drug Administration provides 19 allergen RMs, and our research team also proved 9 RMs which are important in Korea. In conclusion, allergen standardization is an essential process for the development of reliable treatment and diagnostic reagents, and allergy specialist should be familiar with the concept of allergen standardization.

Comparison between Newly Developed and Commercial Inhalant Skin Prick Test Reagents Using In Vivo and In Vitro Methods

BACKGROUND: We developed skin prick test (SPT) reagents for common inhalant allergens that reflected the real exposure in Korea. The study aim was to evaluate diagnostic usefulness and allergen potency of our inhalant SPT reagents in comparison with commercial products. METHODS: We produced eight common inhalant allergen SPT reagents using total extract (Prolagen): Dermatophagoides farinae, Dermatophagoides pteronyssinus, oak, ragweed, mugwort, Humulus japonicus pollens, as well as cat and dog allergens. We compared the newly developed reagents with three commercially available SPT reagents (Allergopharma, Hollister-Stier, Lofarma). We measured total protein concentrations, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), major allergen concentration, and biological allergen potencies measured by immunoglobulin E (IgE) immunoblotting and ImmunoCAP inhibition test. RESULTS: Diagnostic values of these SPT reagents were expressed as positivity rate and concordance rate of the results from ImmunoCAP allergen-specific IgE test in 94 allergic patients. In vitro analysis showed marked differences in protein concentrations, SDS-PAGE features, major allergen concentrations, and biological allergen potencies of four different SPT reagents. In vivo analysis showed that positive rates and concordance rates of Prolagen® SPT reagents were similar compared to the three commercial SPT reagents. CONCLUSION: The newly developed Prolagen® inhalant SPT reagents are not inferior to the commercially available SPT reagents in allergy diagnosis.

IgE Cross-Reactivity between Humulus japonicus and Humulus lupulus

PURPOSE: Japanese hop (Humulus japonicus) is a major cause of weed pollinosis in East Asia. However, supplies of commercial allergen extract from this plant have not met clinical demand. The pollen of common hop (Humulus lupulus), a closely related species, may provide an alternative source if there is strong IgE cross-reactivity between these two species. We aimed to compare the IgE cross-reactivity and allergenicity of common hop and Japanese hop pollen. MATERIALS AND METHODS: Cross-reactivity was measured by inhibition ELISA. One- and two-dimensional (2D) gel analyses combined with IgE immunoblotting and mass spectrometry [liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS)] were performed to detect IgE-reactive pollen components. RESULTS: Up to 16.7% of IgE reactivity to Japanese hop was inhibited by common hop. A 12-kDa protein component of Japanese hop pollen that showed the most potent IgE reaction was absent from common hop. Six IgE-reactive components from Japanese hop were detected by 2D gel electrophoresis and LC-ESI-MS/MS, but showed low Mascot scores, preventing positive identification. CONCLUSION: No significant IgE cross-reaction was observed for Japanese and common hop pollen allergens. Development of allergy diagnostic and immunotherapeutic reagents based on Japanese hop pollen are urgently needed.

Monoclonal Antibodies to Recombinant Fag e 3 Buckwheat Allergen and Development of a Two-site ELISA for Its Quantification

PURPOSE: Buckwheat is a major cause of anaphylaxis, and Fag e 3 is the key major allergen in buckwheat. However, an immunoassay system for the quantification of Fag e 3 has yet to be developed. METHODS: We developed a 2-site enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies (mAbs) produced against recombinant Fag e 3. We applied this ELISA to quantify native Fag e 3 in total buckwheat extract. RESULTS: Four clones of mAbs were produced, and all recognized vicilin allergens not only from buckwheat, but also from peanut and walnut. However, the ELISA using these antibodies was only able to quantify Fag e 3 in the total extract after addition of 1% sodium dodecyl sulphate (SDS) and heating, which facilitated dissociation of the allergen. The detection limit of the developed 2-site ELISA was 0.8 µg/mL. The measurement of Fag e 3 in the total extract of buckwheat showed that approximately 12% of protein in total buckwheat extract was Fag e 3. CONCLUSIONS: We have developed an ELISA system for the quantification of the group 3 buckwheat allergen, Fag e 3, specifically. This assay will be useful for standardization of buckwheat allergens and monitoring of buckwheat contamination in foods.

Erratum: In Vitro Evaluation of Allergen Potencies of Commercial House Dust Mite Sublingual Immunotherapy Reagents

Corrections for Table. 1 in page 125 are needed. We apologize for any inconvenience that this may have caused.

Soluble CD93 in Serum as a Marker of Allergic Inflammation

PURPOSE: CD93 is receiving renewed attention as a biomarker of inflammation. We aimed to evaluate the potential for serum sCD93 to serve as a novel biomarker for allergic inflammation. MATERIALS AND METHODS: We enrolled 348 subjects with an allergic disease [allergic rhinitis (AR), chronic spontaneous urticaria (CSU), or bronchial asthma (BA)], including 14 steroid-naïve BA patients who were serially followed-up. RESULTS: The serum sCD93 levels (ng/mL) in patients with exacerbated AR (mean±standard deviation, 153.1±58.4) were significantly higher than in patients without AR (132.2±49.0) or with stable AR (122.3±42.1). Serum sCD93 levels in exacerbated CSU (169.5±42.8) were also significantly higher than those in non-CSU (132.4±51.6) and stable CSU (122.8±36.2). This trend was also seen in BA. Serum levels in patients with ICS-naïve BA (161.4±53.1) were significantly higher than those in healthy controls without BA (112.2±30.8), low- and medium-dose ICS users. Serum sCD93 levels in high-dose ICS users (72.2±20.6) were significantly lower than those in low- and medium-dose users. The serum sCD93 levels in steroid-naïve patients with BA (195.1±72.7) decreased after ICS use for 4 weeks (134.4±42.8) and 8 weeks (100.7±13.4), serially. CONCLUSION: Elevated serum sCD93 levels reflected exacerbated status of allergic diseases, including CSU, AR, and asthma. ICS use significantly diminished serum sCD93 levels in steroid-naïve patients with BA. This result may suggest sCD93 in serum as a therapeutic marker for allergic inflammation.

Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori

Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm.

Cross-Reactivity between Oak and Birch Pollens in Korean Tree Pollinosis

Oak and birch trees belong to Fagales order. Specific IgE to pollen allergens of both trees are frequently found in Korea pollinosis patients. Oak trees which comprise 40% of forest area are common in Korea. However, birch trees are sparse. We compared the allergenicity of pollen extracts of white oak, sawtooth and Mongolian oaks which are prevalent species in Korea, with the pollen extract of birch. The cross-reactivity of four pollen extracts was examined with pooled sera of 12 patients by ELISA, immunoblotting and CAP inhibitions. A protein of 17 kDa, putatively homologous to a major birch allergen Bet v 1, displayed strong IgE reactivity from white oak and sawtooth oak pollen extract but not from Mongolian oak pollen. Notably, a 23-kDa protein from sawtooth and white oaks showed strong IgE reactivity and inhibited by Bet v 1. IgE binding to white oak was inhibited a maximum of 94.6% by white oak, 93.4% by sawtooth oak, 83.2% by Mongolian oak, and 68.8% by birch. Furthermore, sawtooth oak, white oak, and Mongolian oak extracts were able to inhibit up to 78.5%, 76.6% and 67.3% of IgE binding to birch extract, while birch extract itself inhibited up to 94.3%. Specific IgE to Bet v 1 was inhibited a maximum of 79.1% by sawtooth oak, 77.4% by white oak, and 72.7% by Mongolian oak, while 81.5% inhibition was shown by birch. Bet v 1 was able to partially inhibit its homologous molecules from sawtooth oak and white oak in immunoblotting. Birch pollen extract was found to be cross-reactive primarily with Bet v 1-homologous allergen from oak pollens in Korea pollinosis patients. Considering the sparseness of birch tree in Korea, oak, especially sawtooth oak may be the main cause of tree pollinosis in Korea, rather than birch.

Physical and biochemical characteristics of allergens

What makes a certain molecule to elicit allergic responses? It has been a long-running question in allergology and immunology. Molecular properties of allergens have been characterized for last 30 years. However, it has become evident that allergen alone cannot induce allergic reactions. The way of introduction to the immune system and adjuvant-like activity of concomitantly administered molecules are thought to be important. Physical properties which facilitate delivery may characterize inhalant allergens. Buoyant and sticky antigens with small molecular weight (10-50 kDa) may be carried by particles and remain airborne. Most allergens could be grouped into allergen families according to biochemical properties. Protease, lipid-binding/transfer protein, actin-binding protein, Ca-binding protein, α-amylase/trypsin inhibitor, and pectate lyase account for a significant number of allergens. Biochemical properties which enhance the activation of Th2-immune responses could be another characteristic of allergens. The protease activity of allergens can help break the skin barrier or mucus membrane and its penetration into the body. The capacity of allergen to carry immunologically active substances could increase the allergenicity. Lipid-binding ability is believed to play a role in this aspect. Danger signals, such as endotoxin, β-glucan, and chitin derived from the pathogens, commensals and from the environment can enhance the immune response to allergens. The known characteristics of food allergens are resistance to heat, acid, and digestive enzymes. However, food processing makes it more complex. Understanding the intrinsic properties of allergens may shed light on the mechanisms on the pathogenesis of allergic disorders and improve the diagnostic and therapeutic approaches.

Different Responses in Induction of Allergen Specific Immunoglobulin G4 and IgE-Blocking Factors for Three Mite Subcutaneous Immunotherapy Products

PURPOSE: Specific immunoglobulin G4 (sIgG4) and immunoglobulin E (IgE)-blocking factors produced by subcutaneous immunotherapy (SCIT) play a critical role in the induction of allergen tolerance. However, comparative studies of available SCIT reagents on the induction of sIgG4 are limited. We compared increases in sIgG4 for three different house dust mite (HDM) SCIT reagents. MATERIALS AND METHODS: Seventy-two HDM sensitized allergic patients were enrolled and classified into four groups: 1) control (n=27), 2) SCIT with Hollister-Stier® (n=19), 3) Tyrosine S® (n=16), and 4) Novo-Helisen® (n=10). Levels of specific IgE (sIgE), sIgG4, and IgE blocking factor to Dermatophagoides farinae (D. farinae) were measured using ImmunoCAP (sIgE, sIgG4) and enzyme-linked immunosorbent assay (ELISA) (IgE-blocking factors). Levels were measured before and 13.9±6.6 months after the SCIT. The allergen specificity and the induction levels of sIgE and sIgG4 were confirmed by immunoblot analysis. RESULTS: After SCIT, sIgG4 levels to D. farinae increased significantly; however, the increases differed significantly among the SCIT groups (p<0.001). Specific IgG4 levels to D. farinae were highest in Hollister-Stier® (3.7±4.1 mg/L), followed by Novo-Helisen® (2.2±2.3 mg/L) and Tyrosine S® (0.7±0.5 mg/L). In addition, patients who were administered using Hollister-Stier® showed the most significant decrease in IgE/IgG4 ratio (p<0.001) and increase in blocking factor (p=0.009). Finally, according to IgE immunoblot results, the Hollister-Stier® group showed the most significant attenuation of IgE binding patterns among others. CONCLUSION: Currently available SCIT reagents induce different levels of specific IgG4, IgE/IgG4 ratio, and IgE-blocking factor.

Different Responses in Induction of Allergen Specific Immunoglobulin G4 and IgE-Blocking Factors for Three Mite Subcutaneous Immunotherapy Products

PURPOSE: Specific immunoglobulin G4 (sIgG4) and immunoglobulin E (IgE)-blocking factors produced by subcutaneous immunotherapy (SCIT) play a critical role in the induction of allergen tolerance. However, comparative studies of available SCIT reagents on the induction of sIgG4 are limited. We compared increases in sIgG4 for three different house dust mite (HDM) SCIT reagents. MATERIALS AND METHODS: Seventy-two HDM sensitized allergic patients were enrolled and classified into four groups: 1) control (n=27), 2) SCIT with Hollister-Stier® (n=19), 3) Tyrosine S® (n=16), and 4) Novo-Helisen® (n=10). Levels of specific IgE (sIgE), sIgG4, and IgE blocking factor to Dermatophagoides farinae (D. farinae) were measured using ImmunoCAP (sIgE, sIgG4) and enzyme-linked immunosorbent assay (ELISA) (IgE-blocking factors). Levels were measured before and 13.9±6.6 months after the SCIT. The allergen specificity and the induction levels of sIgE and sIgG4 were confirmed by immunoblot analysis. RESULTS: After SCIT, sIgG4 levels to D. farinae increased significantly; however, the increases differed significantly among the SCIT groups (p<0.001). Specific IgG4 levels to D. farinae were highest in Hollister-Stier® (3.7±4.1 mg/L), followed by Novo-Helisen® (2.2±2.3 mg/L) and Tyrosine S® (0.7±0.5 mg/L). In addition, patients who were administered using Hollister-Stier® showed the most significant decrease in IgE/IgG4 ratio (p<0.001) and increase in blocking factor (p=0.009). Finally, according to IgE immunoblot results, the Hollister-Stier® group showed the most significant attenuation of IgE binding patterns among others. CONCLUSION: Currently available SCIT reagents induce different levels of specific IgG4, IgE/IgG4 ratio, and IgE-blocking factor.

Standardization of Weed Pollen Extracts, Japanese Hop and Mugwort, in Korea

PURPOSE: Japanese hop (Humulus spp.) and mugwort (Artemisia spp.) are notable causes of autumn pollinosis in East Asia. However, Japanese hop and mugwort pollen extracts, which are widely used for the diagnosis, have not been standardized. This study was performed to standardize Japanese hop and mugwort pollen extracts. MATERIALS AND METHODS: Allergen extracts were prepared in a standardized way using locally collected Humulus japonicus and purchased Artemisia vulgaris pollens. The immunoglobulin E (IgE) reactivities of prepared extracts were compared with commercial extracts via IgE immunoblotting and inhibition analyses. Intradermal skin tests were performed to determine the bioequivalent allergy unit (BAU). RESULTS: The IgE reactive components of the extracts via IgE immunoblotting were similar to those of commercial extracts. A 11-kDa allergen showed the strongest IgE reactivity in Japanese hop, as did a 28-kDa allergen in mugwort pollen extracts. Allergenic potencies of the investigatory Japanese hop and mugwort extracts were essentially indistinguishable from the commercial ones. Sums of erythema of 50 mm by the intradermal skin test (SigmaED50) were calculated to be 14.4th and 13.6th three-fold dilutions for Japanese hop and mugwort extracts, respectively. Therefore, the allergenic activity of the prepared extracts was 90827.4 BAU/mg for Japanese hop and 34412 BAU/mg for mugwort. CONCLUSION: We produced Japanese hop and mugwort pollen extracts using a standardized method. Standardized Japanese hop and mugwort pollen extracts will facilitate the production of improved diagnostic and immunotherapeutic reagents.

Allergenic Characterization of a Novel Allergen, Homologous to Chymotrypsin, from German Cockroach

PURPOSE: Cockroach feces are known to be rich in IgE-reactive components. Various protease allergens were identified by proteomic analysis of German cockroach fecal extract in a previous study. In this study, we characterized a novel allergen, a chymotrypsin-like serine protease. METHODS: A cDNA sequence homologous to chymotrypsin was obtained by analysis of German cockroach expressed sequence tag (EST) clones. The recombinant chymotrypsins from the German cockroach and house dust mite (Der f 6) were expressed in Escherichia coli using the pEXP5NT/TOPO vector system, and their allergenicity was investigated by ELISA. RESULTS: The deduced amino acid sequence of German cockroach chymotrypsin showed 32.7 to 43.1% identity with mite group 3 (trypsin) and group 6 (chymotrypsin) allergens. Sera from 8 of 28 German cockroach allergy subjects (28.6%) showed IgE binding to the recombinant protein. IgE binding to the recombinant cockroach chymotrypsin was inhibited by house dust mite chymotrypsin Der f 6, while it minimally inhibited the German cockroach whole body extract. CONCLUSIONS: A novel allergen homologous to chymotrypsin was identified from the German cockroach and was cross-reactive with Der f 6.

In Vitro Evaluation of Allergen Potencies of Commercial House Dust Mite Sublingual Immunotherapy Reagents

PURPOSE: The clinical efficacy of allergen-immunotherapy is known to be dose dependent. However, optimal maintenance dosage has not yet been determined for sublingual immunotherapy (SLIT). Furthermore, since companies adopt their own units for expression of allergenicity, the allergen concentrations of individual reagents cannot be compared easily. We sought to measure and compare the allergenicities of 3 commercially available house dust mite (HDM) SLIT regents and a subcutaneous immunotherapy reagent. METHODS: We measured the HDM allergenic potency of the maintenance dosages of three SLIT reagents: Staloral(R) (300 index of reactivity [IR] /mL, recommended maintenance dosage [MD]: 120 IR), SLITone(R) (1,000 standard therapeutic unit [STU]/mL, recommended MD: 200 STU), Wolwopharma(R) (100 microg/mL, recommended MD: 20 microg), and subcutaneous immunotherapy regents of Hollister-Stier (10,000 allergy unit [AU] /mL). The allergenic potency was assessed by measuring the total protein concentrations, mite group 1 and 2 allergens using 2-site ELISA, and an inhibition test against IgE specific to Dermatophagoides farinae and Dermatophagoides pteronyssinus. RESULTS: The protein content of the Wolwopharma(R) reagent was 1.5-261.4 times higher than that of the other 2 SLIT reagents. The concentration of group 1 major allergens in Staloral(R) (132.03 microg/mL) was 33- to 44.5-fold higher than in SLITone(R) (4.00 microg/mL) and Wolwopharma(R) (2.97 microg/mL). The concentration of group 2 major allergen was also 8.9- to 10.5-fold higher in Staloral(R) (15.7 microg/mL) than in SLITone(R) (1.8 microg/mL) or Wolwopharma(R) (1.5 microg/mL). An ELISA inhibition study against HDM-specific IgE showed that the allergen potency of Staloral(R) reagent is 8.5-fold and 21-fold higher than that of SLITone(R) or Wolwopharma(R), respectively. The differences between the maintenance dosages are further exaggerated by the differences in the recommended volumes of SLIT reagents. CONCLUSIONS: The allergen potencies of commercially available HDM SLIT reagents are markedly different. Consensus regarding the optimal allergen concentration for SLIT reagents used to treat HDM respiratory allergies is needed.

Performance of the PROTIA(TM) Allergy-Q(R) System in the Detection of Allergen-specific IgE: A Comparison With the ImmunoCAP(R) System

PURPOSE: The PROTIA(TM) Allergy-Q(R) enzyme immunoassay (EIA) is a recently developed screening assay for specific immunoglobulin E (sIgE) for multiple allergens. The ImmunoCAP(R) fluorescent EIA (FEIA) system is the most widely used method for sIgE detection. In this study, we evaluated the performance of the Allergy-Q(R) system compared to the ImmunoCAP(R) system. METHODS: We compared the 2 systems using sera from 260 Korean allergy patients suffering from asthma (26.5%), allergic rhinitis (42.3%), atopic dermatitis (67.7%), and food allergy (18.1%). We compared sIgE-measurement results for 7 inhalant allergens, 5 food allergens, and 4 microorganism allergens. RESULTS: Overall, 1,799 paired assay results were analyzed. Except mugwort and alternaria, most of the allergen-sIgE results showed intra-class correlation coefficients of >0.5. Inter-assay class associations were reliable for most allergens (gamma=0.858-0.987, P<0.001). Passing-Bablok regression analysis showed multiple differences in intercept and slope. The inter-method concordance was moderate to substantial for most allergens (kappa=0.713-0.898, P<0.001). CONCLUSIONS: The PROTIA(TM) Allergy-Q(R) EIA system exhibited good detection performance compared to the ImmunoCAP(R) FEIA system in Korean allergic patients. However, because of methodological differences between the 2 assays, careful clinical implication is required for the interpretation of Allergy-Q(R) EIA results.

Profiles of IgE Sensitization to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20 in Korean House Dust Mite Allergy Patients

PURPOSE: Measurement of IgE specific to purified house dust mite (HDM) allergens may improve allergy diagnosis. This study aimed to investigate the sensitization profiles of Korean HDM allergic subjects suffering from respiratory allergy and atopic dermatitis (AD) to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20. METHODS: Recombinant HDM allergens were produced in Pichia pastoris (Der f 1) or Escherichia coli (5 allergens). IgE reactivity to the individual recombinant allergens and total extract of mite was assessed by ELISA. RESULTS: Der f 1 was recognized by 79.1%, Der f 2 by 79.1%, Der f 6 by 9.3%, Der f 8 by 6.2%, Der f 10 by 6.2%, and Der f 20 by 6.6% of the patients' sera tested, while the prevalence of IgE reactivity to total mite extract was 94.7%. Combination of Der f 1 and Der f 2 had a sensitivity of 87.6%. Specific IgE to Der f 2 alone was detected from 89.4% of HDM-sensitized respiratory allergy subjects and 92.3% to the combination of the 2 major allergens Der f 1 and Der f 2. However, sera from fewer patients with AD, namely 72.4% and 71.0%, recognized Der f 1 and Der f 2, respectively. The combination of 2 major allergens allowed diagnosis of 84.5% of the AD patients. No correlation between sensitization to specific allergens and HDM allergy entity was found. CONCLUSIONS: Der f 2 was the most frequently sensitized allergen among the HDM-sensitized respiratory and AD patients in Korea, and the combination of the group 1 and 2 major allergens increased the diagnostic sensitivity. Minor allergens did not significantly improve diagnostic sensitivity. However, further studies are needed to analyze the relationship between sensitization to other HDM allergens and the disease entity of the HDM allergy.

The effects of a newsletter on bedding control on house dust mite allergen concentrations in childcare centers in Korea

OBJECTIVES: Bedding in childcare centers (CCCs) can hold house dust mite (HDM) allergens. This study examined whether HDM allergen levels can be reduced through the distribution of an educational newsletter on bedding control to parents of CCC children in Korea. METHODS: All 38 CCCs were measured for Der 1 (sum of Der f 1 and Der p 1) concentrations on classroom floors and bedding before the intervention. Educational newsletters on children’s bedding control were sent to 21 CCCs by mail, and teachers were asked to distribute the newsletters to the parents of the children (intervention group). The remaining 17 CCCs were not sent newsletters (control group). The measurement of Der 1 concentrations in 38 CCCs was repeated after the intervention. Dust samples were collected with a vacuum cleaner and analyzed using enzyme-linked immunosorbent assay methods. RESULTS: The Der 1 concentrations on the bedding were significantly higher than those on the floors in 38 CCCs at baseline (p<0.05). Although changes of the Der 1 concentrations for the control group (n=17) were not significant, Der 1 concentrations for the intervention group (n=21) decreased significantly from 2077.9 ng/g dust to 963.5 ng/g dust on the floors and from 3683.9 ng/g dust to 610.4 ng/g dust on bedding (p<0.05). CONCLUSIONS: The distribution of educational newsletters on bedding control to parents may be an effective means of controlling HDMs in CCCs.