Sensitization to various minor house dust mite allergens is greater in patients with atopic dermatitis than in those with respiratory allergic disease.

BACKGROUND: Various allergenic proteins are produced by house dust mites (HDM). However, the allergenicity and clinical implications of these allergens are unknown. OBJECTIVE: The purpose of this study was to identify allergens in Dermatophagoides farinae and elucidate the sensitization profiles to these in Korean patients suffering from respiratory (allergic rhinitis and/or asthma) and atopic dermatitis symptoms. METHODS: IgE reactivities in sera from 160 HDM allergy patients were analysed by one- and two-dimensional gel electrophoresis and immunoblotting. IgE-reactive components were identified by liquid chromatography-coupled electrospray ionization-tandem mass spectrometry. Nine recombinant mite allergens (Der f 1, Der f 2, Der f 10, Der f 11, Der f 13, Der f 14, Der f 30, Der f 32 and Der f Alt a 10) were produced, and the IgE reactivity in sera to each was determined by ELISAs. RESULTS: Der f 1 and Der f 2 were recognized by IgE in serum samples from 88.1% and 78.1% of all patients, respectively. Patients with respiratory allergies were mainly sensitized to these major allergens, whereas patients with atopic dermatitis symptoms showed polysensitization to major and minor allergen components (including Der f 11, Der f 13, Der f 14, Der f 32 and Der f Alt a 10). CONCLUSIONS: Patients with respiratory allergic disease sensitize to major allergen components of HDM. Those with atopic dermatitis were sensitized to a broader range of minor allergen components of HDM (Der f 11, Der f 13, Der f 14, Der f 32 and Der f Alt a 10).

Allergen-specific immunotherapy induces regulatory T cells in an atopic dermatitis mouse model.

BACKGROUND: Several studies have demonstrated that allergen-specific immunotherapy (SIT) can be an effective treatment for atopic dermatitis (AD). However, there is no relevant mouse model to investigate the mechanism and validate the novel modality of SIT in AD. METHODS: NC/Nga mice with induced AD-like skin lesions received a subcutaneous injection of SIT (an extract of the house dust mite Dermatophagoides farinae [DfE]) or placebo for 5 weeks). Clinical and histological improvements of AD-like skin lesions were examined. The responses of local and systemic regulatory T (Treg) cells, natural killer (NK) cells, B cells, serum immunoglobulin, and T-cell cytokine response to DfE were evaluated to determine the underlying mechanism of the observed results. RESULTS: Specific immunotherapy significantly improved AD-like skin lesions. Histologically, SIT decreased epidermal thickness and reduced inflammatory cell infiltration, especially that of eosinophils. Concomitantly, SIT suppressed Th2 responses and induced local infiltration of Treg cells into the skin. Also, SIT induced the immunoglobulin G4 and attenuated allergen-specific immunoglobulin E. Furthermore, SIT induced local and systemic IL-10-producing Treg cells and regulatory NK cells. CONCLUSION: We established a SIT model on AD mice and showed that our model correlates well with previous reports about SIT-treated patients. Also, we revealed NK cells as another possible resource of IL-10 in SIT. Based on our results, we suggest our SIT model as a useful tool to investigate mechanism of action of SIT and to validate the efficacy of new SIT modalities for the treatment of AD.

Ranitidine-induced anaphylaxis: clinical features, cross-reactivity, and skin testing.

BACKGROUND: Histamine H2 receptor antagonists are commonly prescribed medications and are known to be well tolerated. However, 99 cases of ranitidine-induced anaphylaxis occurred in Korea from 2007 to 2014. OBJECTIVE: The purpose of this study was to determine the incidence, clinical features, and diagnostic methods for ranitidine-induced anaphylaxis. METHODS: Ranitidine-related pharmacovigilance data from 2007 to 2014 were reviewed. Adverse drug reactions with causal relationships were selected, and clinical manifestations, outcomes, and drug-related information were assessed. For further investigation, 8 years of pharmacovigilance data were collected at a single centre. Twenty-three patients participated in in vivo and in vitro studies. Skin tests, oral provocation tests, and laboratory tests were performed, including tests using other kinds of histamine H2 receptor antagonists. RESULTS: Over 7 years, 584 patients suffered adverse reactions to ranitidine. The most common manifestation was cutaneous symptoms. Among them, 99 patients (17.0%) experienced anaphylaxis. In a single-centre study, skin prick tests were positive in 91.7% of ranitidine-induced anaphylaxis patients (11/12); the optimal concentration was 20 mg/mL. Detection of ranitidine-specific immunoglobulin E failed. Cimetidine and proton pump inhibitors showed no cross-reactivity with ranitidine based on the skin prick test, oral provocation test, or clinical determination. Surprisingly, 82.6% of patients reintroduced ranitidine and re-experienced the same adverse reactions because ranitidine was not considered the culprit drug. CONCLUSIONS AND CLINICAL RELEVANCE: Although ranitidine is known as a safe drug, it can also cause diverse adverse reactions, including anaphylaxis. This study demonstrates the need to pay attention to adverse reactions to ranitidine and consider ranitidine as a cause of anaphylaxis.

Allergenicity of recombinant profilins from Japanese hop, Humulus japonicus.

BACKGROUND AND OBJECTIVE: Pollen from Japanese hop, Humulusjaponicus, is a major cause of pollinosis in Korea. Profilin (15 kDa) from Humulus scandens has been associated with strong allergenicity in allergic Chinese patients. Profilin has also been detected in pollen extract from Korean Japanese hop by proteomic analysis and immunoglobulin (Ig) E immunoblotting. However, the allergenicity of allergens isolated from Japanese hop has not been investigated in Korean individuals. This study was undertaken to produce recombinant profilin from Japanese hop and evaluate its allergenicity. METHODS: Complementary DNA sequences encoding 2 isoallergens were cloned by reverse transcription polymerase chain reaction and their recombinant proteins expressed in Escherichia coli. The IgE-binding reactivities of the recombinant allergens were assessed by enzyme-linked immunosorbent assay. RESULTS: The deduced amino acid sequences of the H. japonicus profilins were 68.7% to 80.2% homologous with profilins from mugwort (Art v 4), ragweed (Amb a 14), and birch (Bet v 2). Two isoallergens of profilin from H. japonicus were 78.2% identical. Notably, the cDNA sequences of these 2 isoallergens were 98.5% (AY268422) and 98.7% (AY268424) identical to those of H. scandens. Serum samples from Japanese hop-sensitized individuals showed 12.9% IgE reactivity to both of the recombinant profilin isoallergens from H. japonicus, indicating that profilin may not be an allergenically dominant component of Japanese hop pollen. The recombinant profilins showed only 0% to 9.3% inhibition of the crude extract. CONCLUSIONS: Two isoallergens of profilin that are highly conserved with those of mugwort, ragweed, and birch were identified in H. japonicus. Profilins from Japanese hop pollen may play a minor role in the pathogenesis of pollinosis in Koreans.

Characterization of the major allergens of Pachycondyla chinensis in ant sting anaphylaxis patients.

BACKGROUND: The ant species Pachycondyla chinensis, which has spread from Far Eastern Asia to New Zealand and North America, induces anaphylactic reactions in human with its sting. However, the major allergens of P. chinensis have not yet been characterized. METHODS: We selected seven patients with histories of anaphylaxis induced by P. chinensis. Two-dimensional electrophoresis (2-DE) was used to identify the major allergens. We subsequently performed Western blots for P. chinensis-specific IgEs, N-terminal amino acid sequencing, ESI-MS/MS, and RT-PCR using primers based on the N-terminal sequence. RESULTS: Six of the anaphylactic subjects had an IgE specific to a 23 kDa allergen of P. chinensis. Two candidates for major allergens, 23 kDa (pI 8.7) and 25 kDa (pI 6.2), were revealed by 2-DE using P. chinensis-specific IgE immunoblotting. In N-terminal sequencing and ESI-MS/MS analysis, 23 kDa (pI 8.7) and 25 kDa (pI 6.2) allergens, belonging to the protein families of antigen 5, were identified and share marked amino acid sequence similarity. The 23 kDa allergen is 206 amino acids in length and homology searches showed 54.0% and 50.0% homology with Sol i 3 and Ves v 5, respectively. CONCLUSION: The major allergens of P. chinensis are 23 kDa (pI 8.7) and 25 kDa (pI 6.2) proteins that belong to the antigen 5 family of proteins.

Regulation of German cockroach extract-induced IL-8 expression in human airway epithelial cells.

BACKGROUND: Cockroaches have been known as a cause of respiratory allergies such as asthma. IL-8 plays an integral role in the coordination and persistence of the inflammatory process in the chronic inflammation of the airways in asthma. OBJECTIVE: We investigated the mechanism by which German cockroach extract (GCE) triggers IL-8 release from human airway epithelial cells. METHODS: Chemical inhibitors were pretreated before addition of GCE for promoter activity and protein synthesis of IL-8. The Transcriptional activity of IL-8 promoter was analysed by mutational, deletional anaylsis and electrophoretic mobility shift assay (EMSA). RESULTS: Stimulation of H292 cells with GCE resulted in a time- and concentration-dependent induction of IL-8 transcription and protein synthesis. IL-8 promoter deletion analysis indicated that position -132 to +41 was essential for GCE-induced IL-8 transcription, and mutants with substitutions in activator protein (AP)-1, nuclear factor (NF)-IL6 and NF-kappaB-binding sites revealed a requirement for NF-kappaB and NF-IL6, but not AP-1, in GCE-induced activation of the IL-8 promoter. The DNA-binding activities of NF-kappaB and NF-IL6 were induced by GCE, as determined by EMSA. The chemical inhibition of extracellular signal-regulated kinase (ERK) attenuated GCE-induced transcriptional activity and protein synthesis. In addition, through aprotinin treatment and PAR2 small interfering RNA transfection, it was proven that protease of GCE is consistent with the regulation of GCE-induced IL-8. CONCLUSION: We conclude that GCE with protease activity-induced IL-8 expression is regulated by transcriptional activation of NF-kappaB and NF-IL6 coordinating with the ERK pathway in human airway epithelial cells.

Localization of Der f 2 in the gut and fecal pellets of Dermatophagoides farinae.

BACKGROUND: House dust mite derived materials are known to be the most potent agent inducing allergic diseases. Localization of Der f 2 was attempted to specify the sites and concentrations of Der f 2 within the mite, which may indicate the importance of secreted materials and nonexcreted body components as allergen sources. METHODS: Serial cryostat sections of embedded live mites and the fecal pellets, collected by brush, were immunoprobed using monoclonal antibody (mAb) 2F38 raised against recombinant (r) Der f 2. RESULTS: Highest concentrations were found in the anterior midgut, implying that this is the site of Der f 2 synthesis and secretion. Digestive material and defecated fecal pellets were also labeled with mAb. CONCLUSIONS: Our results show that the major allergen, Der f 2, found in the house dust mite D. farinae is derived from the digestive tract, and is concentrated in the feces.

Allergenicity of recombinant Bla g 7, German cockroach tropomyosin.

BACKGROUND: Cockroach infestation may sensitize and elicit allergic responses to genetically predisposed individuals. Invertebrate tropomyosins are a frequent cause of allergy and highly cross-reactive in nature. In this study, we aimed to produce recombinant German cockroach tropomyosin and investigate its allergenicity. METHODS: German cockroach tropomyosin (Bla g 7) was cloned by reverse transcriptase polymerase chain reaction (RT-PCR). The cloned cDNA was over-expressed in Escherichia coli and purified by affinity chromatography using Ni-nitrilotriacetic (NTA) acid resin. The allergenicity of the recombinant tropomyosin was examined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The cloned Bla g 7 shared up to 91% amino acid sequence identity with other cockroach tropomyosins. ELISA showed a recombinant Bla g 7 sensitization rate of 16.2% to German cockroach allergic sera. Recombinant tropomyosin was able to inhibit 32.4% of the specific IgE binding to cockroach extract. CONCLUSIONS: Tropomyosin represents a minor allergen in cockroach extracts. It is hoped that recombinant tropomyosin will be useful for further studies and clinical applications.

Monoclonal antibodies to recombinant Der f 2 and development of a two-site ELISA sensitive to major Der f 2 isoallergen in Korea.

BACKGROUND: Der f 2 is a major sensitizing allergen in patients allergic to house dust mites worldwide. Isoforms of Der f 2 have been reported and are known to have different antigenicities. The aim of this study was to facilitate antigenic analysis and to develop an improved method for the detection of Der f 2 isoallergen, which is prevalent in Korea. METHODS: A two-site ELISA was developed with monoclonal antibodies (mAbs) which were produced against recombinant Der f 2 (rDer f 2) and applied to assess Der f 2 in bedding samples. RESULTS: A major isoform of Der f 2, found in Korea, was found to have amino acid variations especially at position 100 from lysine to glutamic acid, which is known to reduce significantly the binding affinity of mAbs when used to assess group 2 allergens. The detection limit of the developed two-site ELISA was determined to be about 8 ng/ml with rDer f 2 and 1 microg/ml with Derntatophagoides farinae crude extract. The average amount of Der f 2 in dust obtained from bedding samples from 89 homes in Seoul was estimated to be 25.61+/-10.70 microg/g dust. CONCLUSIONS: Assays using mAbs for rDer f 2 could be useful for the assessment of environmental allergen exposure and mAbs could be used to further characterize the isoallergens of Der f 2.