341 research outputs found
Evaluation of impermeable covers for bedding in patients with allergic rhinitis
BACKGROUND: Encasing bedding in impermeable covers reduces exposure to
house-dust mites, but the clinical benefit of this intervention as part of
mite-avoidance measures for patients with allergic rhinitis is not known.
We performed a multicenter, randomized, placebo-controlled trial of one
year of use of impermeable bedding covers in the bedrooms of patients with
rhinitis who were sensitized to house-dust mites to determine the effects
on the signs and symptoms of disease. METHODS: Three participating
university medical centers enrolled 279 patients with allergic rhinitis
who were randomly assigned to receive impermeable or non-impermeable
(control) covers for their mattress, pillow, and duvet or blanket. At the
start of the study, all participants received information on general
allergen-avoidance measures. The severity of rhinitis was measured on a
rhinitis-specific visual-analogue scale and by means of a daily symptom
score and nasal allergen provocation testing. We also measured the
concentrations of Dermatophagoides pteronyssinus (Der p1) and D. farinae
(Der f1) in dust from patients' mattresses, bedroom floors, and
living-room floors at base line and after 12 months as a measure of the
efficacy of the intervention. RESULTS: A total
Identification of Natural Bispecific Antibodies against Cyclic Citrullinated Peptide and Immunoglobulin G in Rheumatoid Arthritis
BACKGROUND: Previous studies indicate that natural bispecific antibodies can be readily produced in vivo when the body is simultaneously stimulated with 2 distinct antigens. Patients with rheumatoid arthritis (RA) usually exhibit persistent immune responses to various autoantigens, raising the possibility that natural bispecific antibodies against 2 distinct autoantigens might exist. METHODOLOGY/PRINCIPAL FINDINGS: We identified the presence of natural bispecific antibodies against cyclic citrullinated peptide (CCP) and immunoglobulin G (IgG) in RA patients' sera by means of a double-antigen sandwich enzyme-linked immunosorbent assay (ELISA). The spontaneous emergence of bispecific antibodies was confirmed by mixing different proportions of 1 anti-CCP-positive serum and 1 rheumatoid factor (RF)-positive serum in vitro. Among the tested samples, positive correlations were found between the presence of bispecific antibodies and both IgG4 anti-CCP antibodies and IgG4 RF (r = 0.507, p<0.001 and r = 0.249, p = 0.044, respectively), suggesting that the IgG4 subclass is associated with this phenomenon. Furthermore, bispecific antibodies were selectively generated when several anti-CCP- and RF-positive sera were mixed pairwise, indicating that factors other than the monospecific antibody titers may also contribute to the production of the natural bispecific antibodies. CONCLUSIONS/SIGNIFICANCE: We successfully identified the presence of natural bispecific antibodies. Our results suggest that these antibodies originate from anti-CCP and RF in the sera of RA patients. The natural occurrence of bispecific antibodies in human diseases may provide new insights for a better understanding of the diseases. Further investigations are needed to elucidate their precise generation mechanisms and explore their clinical significance in disease development and progression in a larger study population
Production of Native Bispecific Antibodies in Rabbits
BACKGROUND: A natural bispecific antibody, which can be produced by exchanging Fab arms of two IgG4 molecules, was first described in allergic patients receiving therapeutic injections with two distinct allergens. However, no information has been published on the production of natural bispecific antibody in animals. Even more important, establishment of an animal model is a useful approach to investigate and characterize the naturally occurring antibody. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that a natural bispecific antibody can also be generated in New Zealand white rabbits by immunization with synthesized conjugates. These antibodies showed bispecificity to the components that were simultaneously used to immunize the animals. We observed a trend in our test animals that female rabbits exhibited stronger bispecific antibody responses than males. The bispecific antibody was monomeric and primarily belonged to immunoglobulin (Ig) G. Moreover, bispecific antibodies were demonstrated by mixing 2 purified monospecific antibodies in vivo and in vitro. CONCLUSIONS/SIGNIFICANCE: Our results extend the context of natural bispecific antibodies on the basis of bispecific IgG4, and may provide insights into the exploration of native bispecific antibodies in immunological diseases
Allergenicity assessment of genetically modified cropsâwhat makes sense?
GM crops have great potential to improve food quality, increase harvest yields and decrease dependency on certain chemical pesticides. Before entering the market their safety needs to be scrutinized. This includes a detailed analysis of allergenic risks, as the safety of allergic consumers has high priority. However, not all tests currently being applied to assessing allergenicity have a sound scientific basis. Recent events with transgenic crops reveal the fallacy of applying such tests to GM crops
Laboratorial approach in the diagnosis of food allergy
OBJCTIVE: Review the available laboratory tests used to assist in the diagnosis of IgE-mediated and non-IgE-mediated food allergy. DATA SOURCES: Papers in English and Portuguese published in PubMed and Embase, in the last ten years. Terms searched were food allergy, diagnose and laboratory, isolated and/or associated. DATA SYNTHESIS: The diagnostic approach to food allergy reactions includes a good medical history, laboratory studies, elimination diets and blinded food challenges. More recently, the use of a quantitative measurement of food-specific IgE antibodies has been shown to be more predictive of symptomatic IgE-mediated food allergy. Food-specific IgE serum levels exceeding the diagnostic values indicate that the patient is greater than 95% likely to experience an allergic reaction if he/she ingests the specific food. Such decision point values have been defined just for some foods and inconsistent results were obtained when allergy to the same food was studied in different centers. Food challenges, in particular the double-blind placebo-controlled food challenge (DBPCFC), represent the most reliable way to establish or rule out food hypersensitivity. CONCLUSIONS: A number of recent developments are improving the predictive value of some laboratory tests for the diagnosis of food allergies. However, to date, no in-vitro or in-vivo test shows full correlation with clinical food allergy and the DBPCFC remains the gold standard for the definitive diagnosis of specific food allergies. There is an urgent need for new and fundamentally improved diagnostic approaches, which must be validated in patients with food allergy confirmed by a positive DBPCFC.OBJETIVO: Revisar os exames laboratoriais disponĂveis utilizados no diagnĂłstico da alergia alimentar mediada ou nĂŁo por IgE. FONTES DE DADOS: Artigos publicados em base de dados PubMed e Embase (lĂngua inglesa e portuguesa) nos Ăşltimos dez anos. As palavras-chave utilizadas como fonte de busca foram alergia alimentar, diagnĂłstico e laboratĂłrio, isolados e/ou associados. SĂNTESE DOS DADOS: A abordagem diagnĂłstica das reaçþes alĂŠrgicas a alimentos inclui histĂłria clĂnica completa, estudos laboratoriais, dietas de eliminação e desencadeamentos cegos com alimentos. Recentemente, a medida quantitativa de anticorpos IgE especĂficos a alimentos tem mostrado ser mais preditiva de alergia alimentar sintomĂĄtica mediada por IgE. NĂveis sĂŠricos de IgE especĂfica a alimento que excedam os valores diagnĂłsticos indicam que o paciente tem chance maior que 95% de apresentar uma reação alĂŠrgica se ingerir o alimento em questĂŁo. Estes valores de decisĂŁo foram definidos para alguns alimentos e resultados inconsistentes sĂŁo obtidos ao se estudar diferentes populaçþes. Os desencadeamentos com alimento, especialmente o duplo-cego controlado por placebo (DADCCP), representa a maneira mais confiĂĄvel de estabelecer ou descartar o diagnĂłstico de hipersensibilidade alimentar. CONCLUSĂES: NĂşmero crescente de aquisiçþes tem melhorado o valor preditivo de alguns testes laboratoriais empregados no diagnĂłstico de alergias alimentares. Entretanto, atĂŠ hoje, nĂŁo hĂĄ teste in vitro ou in vivo que mostre correlação completa com a clĂnica da alergia alimentar. O DADCCP continua sendo o padrĂŁo-ouro no diagnĂłstico definitivo de alergia alimentar especĂfica. SĂŁo necessĂĄrias, urgentemente, novas abordagens diagnĂłsticas vĂĄlidadas em pacientes com alergia alimentar confirmada por DADCCP positivo.Universidade Federal de SĂŁo Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUNIFESP-EPM Departamento de PediatriaUniversidade de SĂŁo Paulo Faculdade de Medicina Departamento de PediatriaUniversidade Federal da Bahia Departamento de PediatriaUNIFESP-EPMUniversidade Federal do ParanĂĄ Departamento de PediatriaUNIFESP, EPM, Depto. de PediatriaUNIFESP, EPM Depto. de PediatriaUNIFESP, EPMSciEL
Suggested Improvements for the Allergenicity Assessment of Genetically Modified Plants Used in Foods
Genetically modified (GM) plants are increasingly used for food production and industrial applications. As the global population has surpassed 7 billion and per capita consumption rises, food production is challenged by loss of arable land, changing weather patterns, and evolving plant pests and disease. Previous gains in quantity and quality relied on natural or artificial breeding, random mutagenesis, increased pesticide and fertilizer use, and improved farming techniques, all without a formal safety evaluation. However, the direct introduction of novel genes raised questions regarding safety that are being addressed by an evaluation process that considers potential increases in the allergenicity, toxicity, and nutrient availability of foods derived from the GM plants. Opinions vary regarding the adequacy of the assessment, but there is no documented proof of an adverse effect resulting from foods produced from GM plants. This review and opinion discusses current practices and new regulatory demands related to food safety
Antigen-Specific IgG ameliorates allergic airway inflammation via FcÎł receptor IIB on dendritic cells
<p>Abstract</p> <p>Background</p> <p>There have been few reports on the role of Fc receptors (FcRs) and immunoglobulin G (IgG) in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs) in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa.</p> <p>Methods</p> <p>In FcÎłRIIB deficient (KO) and C57BL/6 (WT) mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA). Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c<sup>+ </sup>MHC class II<sup>+ </sup>cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c<sup>+ </sup>APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs) <it>in vitro </it>were also analysed. Moreover, in FcÎłRIIB KO mice intravenously transplanted dendritic cells (DCs) differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL).</p> <p>Results</p> <p>In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c<sup>+ </sup>MHC class II<sup>+ </sup>cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c<sup>+ </sup>APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcÎłRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously.</p> <p>Conclusion</p> <p>Antigen-specific IgG ameliorates allergic airway inflammation via FcÎłRIIB on DCs.</p
Graph based study of allergen cross-reactivity of plant lipid transfer proteins (LTPs) using microarray in a multicenter study.
The study of cross-reactivity in allergy is key to both understanding. the allergic response of many patients and providing them with a rational treatment In the present study, protein microarrays and a co-sensitization graph approach were used in conjunction with an allergen microarray immunoassay. This enabled us to include a wide number of proteins and a large number of patients, and to study sensitization profiles among members of the LTP family. Fourteen LTPs from the most frequent plant food-induced allergies in the geographical area studied were printed into a microarray specifically designed for this research. 212 patients with fruit allergy and 117 food-tolerant pollen allergic subjects were recruited from seven regions of Spain with different pollen profiles, and their sera were tested with allergen microarray. This approach has proven itself to be a good tool to study cross-reactivity between members of LTP family, and could become a useful strategy to analyze other families of allergens
Reduction of Cross-Reactive Carbohydrate Determinants in Plant Foodstuff: Elucidation of Clinical Relevance and Implications for Allergy Diagnosis
Background: A longstanding debate in allergy is whether or not specific immunoglobulin-E antibodies (sIgE), recognizing cross-reactive carbohydrate determinants (CCD), are able to elicit clinical symptoms. In pollen and food allergy, $20% of patients display in-vitro CCD reactivity based on presence of a1,3-fucose and/or b1,2-xylose residues on N-glycans of plant (xylose/fucose) and insect (fucose) glycoproteins. Because the allergenicity of tomato glycoallergen Lyc e 2 was ascribed to N-glycan chains alone, this study aimed at evaluating clinical relevance of CCD-reduced foodstuff in patients with carbohydrate-specific IgE (CCD-sIgE).
Methodology/Principal Findings: Tomato and/or potato plants with stable reduction of Lyc e 2 (tomato) or CCD formation in general were obtained via RNA interference, and gene-silencing was confirmed by immunoblot analyses. Two different CCD-positive patient groups were compared: one with tomato and/or potato food allergy and another with hymenopteravenom allergy (the latter to distinguish between CCD- and peptide-specific reactions in the food-allergic group). Nonallergic and CCD-negative food-allergic patients served as controls for immunoblot, basophil activation, and ImmunoCAP analyses. Basophil activation tests (BAT) revealed that Lyc e 2 is no key player among other tomato (glyco)allergens. CCDpositive patients showed decreased (re)activity with CCD-reduced foodstuff, most obvious in the hymenoptera venomallergic but less in the food-allergic group, suggesting that in-vivo reactivity is primarily based on peptide- and not CCDsIgE. Peptide epitopes remained unaffected in CCD-reduced plants, because CCD-negative patient sera showed reactivity similar to wild-type. In-house-made ImmunoCAPs, applied to investigate feasibility in routine diagnosis, confirmed BAT results at the sIgE level.
Conclusions/Significance: CCD-positive hymenoptera venom-allergic patients (control group) showed basophil activation despite no allergic symptoms towards tomato and potato. Therefore, this proof-of-principle study demonstrates feasibility of CCD-reduced foodstuff to minimize âfalse-positive resultsâ in routine serum tests. Despite confirming low clinical relevance of CCD antibodies, we identified one patient with ambiguous in-vitro results, indicating need for further component-resolved diagnosis
Analysis of the Effects of Polymorphism on Pollen Profilin Structural Functionality and the Generation of Conformational, T- and B-Cell Epitopes
An extensive polymorphism analysis of pollen profilin, a fundamental regulator of the actin cytoskeleton dynamics, has been performed with a major focus in 3D-folding maintenance, changes in the 2-D structural elements, surface residues involved in ligands-profilin interactions and functionality, and the generation of conformational and lineal B- and T-cell epitopes variability.
Our results revealed that while the general fold is conserved among profilins, substantial structural differences were found, particularly affecting the special distribution and length of different 2-D structural elements (i.e. cysteine residues), characteristic loops and coils, and numerous micro-heterogeneities present in fundamental residues directly involved in the interacting motifs, and to some extension these residues nearby to the ligand-interacting areas. Differential changes as result of polymorphism might contribute to generate functional variability among the plethora of profilin isoforms present in the olive pollen from different genetic background (olive cultivars), and between plant species, since biochemical interacting properties and binding affinities to natural ligands may be affected, particularly the interactions with different actin isoforms and phosphoinositides lipids species.
Furthermore, conspicuous variability in lineal and conformational epitopes was found between profilins belonging to the same olive cultivar, and among different cultivars as direct implication of sequences polymorphism. The variability of the residues taking part of IgE-binding epitopes might be the final responsible of the differences in cross-reactivity among olive pollen cultivars, among pollen and plant-derived food allergens, as well as between distantly related pollen species, leading to a variable range of allergy reactions among atopic patients. Identification and analysis of commonly shared and specific epitopes in profilin isoforms is essential to gain knowledge about the interacting surface of these epitopes, and for a better understanding of immune responses, helping design and development of rational and effective immunotherapy strategies for the treatment of allergy diseases. [EN]This study was supported by the following European Regional Development Fund co-financed grants: MCINN BFU 2004-00601/BFI, BFU 2008-00629, BFU2011-22779, CICE (Junta de AndalucĂa) P2010-CVI15767, P2010-AGR6274 and P2011-CVI-7487, and by the coordinated project Spain/Germany MEC HA2004-0094. JCJ-L thanks Spanish CSIC and the European Marie Curie research program for his I3P-BPD-CSIC, and PIOF-GA-2011-301550 grants, respectively.Peer reviewe
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