Sensitization to blackgram in patients with bronchial asthma and rhinitis: clinical evaluation and characterization of allergens

Seafood product safety: A hybrid graphene/gold-based electrochemical immunosensor for fish allergen analysis

Seafood product labels with accurate allergen contents can avoid and/or minimize allergic reactions. Therefore, an electrochemical immunosensor for the analysis of β-parvalbumin (β-PV, a major fish allergen) was developed. Screen-printed carbon electrodes were nanostructured with reduced graphene oxide and gold nanoparticles. The platform was characterized by scanning electron microscopy and elemental analysis. In a sandwich-type assay (∼75 min), the antigen-antibody interaction was detected by chronoamperometry using horseradish peroxidase and TMB-H2O2. A linear range of 25-3000 ng/mL, a sensitivity of 2.99 µA.mL/ng, and a limit of detection of 9.9 ng/mL (corresponding to 0.40 ng in the analysed aliquot) were obtained. The selectivity and possible interferences were assessed by analysing several other food allergens and a marine toxin. The sensor was applied to the analysis of 17 commercial foods and the effect of culinary processing (e.g., grilled, canned, smoked) on the β-PV concentration was assessed. Traces of β-PV were successfully quantified and ELISA was used to assess the results.

Pattern of Food Allergen Sensitivity Amongst Adult Allergic Rhinitis Patients: A Four Year Central Indian Study

AIMS

Only limited Indian data is available regarding the food allergy pattern among allergic rhinitis patients in Indian population. This study aims to assess the pattern of food allergen sensitivity amongst allergic rhinitis patients in central India.

MATERIAL AND METHODS

A total of 218 subjects with allergic rhinitis were enrolled in the study (from May 2018 to August 2022). Skin prick test was done in all subjects with proper technique and precautions by using 125 common food allergens and 75 aero allergens. The test readings were noted after 20 minutes by comparing the wheals so formed with the negative control of Saline and positive control of Histamine. Any reaction with a wheal diameter of 3mm or greater was considered as positive.

RESULTS

While test results of both food and inhalant allergens were issued to individual patients, this study was restricted to detection and analysis of pattern of food allergens. Our study observed male preponderance with predominantly a third decade affliction. The most common food allergen in the study population was beetle nut (29.3%) followed by chilli powder and spinach (28.8% each).

CONCLUSION

Along with aeroallergens, food allergens are also important provocateurs of allergic rhinitis. Diagnosing the offending food allergens and its avoidance reduces patient morbidity, need for pharmaceutical agents and subsequently drug dependence and its side effects. Offering subjects a replacement diet with food items of similar taste and nutritive character helps in sustainable avoidance therapy.

In silico tools to assess the potential allergenicity of shiitake mushrooms (Lentinula edodes)

BACKGROUND

Computational tools may have an edge over conventional methods for the preliminary evaluation of food allergenicity. In this study, the allergenic potential of Lentinula edodes was evaluated and validated using in silico tools.

RESULTS

The potential cross-reactivity of mushroom proteins with fungal allergens was determined using sequence alignment - the Fast Alignment (FASTA) and Basic Local Alignment Search Tool (BLAST) algorithm. Eight L. edodes proteins were cross-reactive with allergens from fungal origin, showing 52%-89% sequence identity using FASTA algorithm-based alignment. The BLAST data were corroborated by percentage identity and query coverage. Physico-chemical property-based allergenicity was deciphered by AlgPred, Allermatch, and AllergenFP software, which predicted six out of eight proteins as potential allergens. Sequence alignment showed 66%-86% conservancy between mushroom protein and known fungal allergens. Secondary structure and amino acid composition supported structural affinity between query and fungal proteins. Three-dimensional structures of five mushroom proteins were generated, quality assessed, and superimposed with fungal allergens, suggesting possible allergenicity of mushroom proteins. An enzyme-linked immunosorbent assay (ELISA) demonstrated immunoglobulin E (IgE) binding in 13 out of 21 food-hypersensitive patients' sera.

CONCLUSION

In silico tools provide preliminary indications about the potential allergenicity and cross-reactivity of mushroom proteins. This approach may be used for the prelusive allergenicity assessment of allergen sources. © 2022 Society of Chemical Industry.

Ranking of 10 legumes according to the prevalence of sensitization as a parameter to characterize allergenic proteins

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10 different legumes extracts could be ranked based on the variations in the prevalence of sensitization.

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Variations in the prevalence of sensitization allowed for ranking of 18 different individual legume proteins.

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Ranking can be used to select reference proteins to develop predictive assays for the assessment of the sensitizing potential of novel proteins.

Predicting the allergenicity of novel proteins is challenging due to the absence of validated predictive methods and a well-defined reference set of proteins. The prevalence of sensitization could be a parameter to select reference proteins to characterize allergenic proteins. This study investigated whether the prevalence of sensitization of legume extracts and proteins can indeed be used for this purpose. A random sample of suspected food-allergic patients (n=106) was therefore selected. 10 extracts (processed and non-processed) and 18 individual proteins (2S albumins, 7S and 11S globulins) from black lentil, blue and white lupine, chickpea, faba bean, green lentil, pea, peanut, soybean, and white bean were isolated and the prevalence of sensitization and the intensity of IgE binding were evaluated. The prevalence of sensitization ranged from 5.7 % (faba bean and green lentil) to 14.2 % (peanut). The prevalence of sensitization for individual legume proteins ranged from 0.0 % for albumin 1 (pea) to 15.1 %–17.9 % for Ara h 1, 2, 3, and 6 (peanut). The prevalence of sensitization correlated strongly with the intensity of IgE binding for individual proteins (p < 0.05, ρ = 0.894), for extracts no correlation was found. The discovered ranking can be used to select reference proteins for the development and validation of predictive in vitro or in vivo assays for the assessment of the sensitizing potential.

An appraisal of allergic disorders in India and an urgent call for action

India is the second most populous country in the world with a population of nearly 1.3 billion, comprising 20% of the global population. There are an estimated 37.5 million cases of asthma in India, and recent studies have reported a rise in prevalence of allergic rhinitis and asthma. Overall, 40-50% of paediatric asthma cases in India are uncontrolled or severe. Treatment of allergic rhinitis and asthma is sub-optimal in a significant proportion of cases due to multiple factors relating to unaffordability to buy medications, low national gross domestic product, religious beliefs, myths and stigma regarding chronic ailment, illiteracy, lack of allergy specialists, and lack of access to allergen-specific immunotherapy for allergic rhinitis and biologics for severe asthma. High quality allergen extracts for skin tests and adrenaline auto-injectors are currently not available in India. Higher postgraduate specialist training programmes in Allergy and Immunology are also not available. Another major challenge for the vast majority of the Indian population is an unacceptably high level of exposure to particulate matter (PM)_2.5 generated from traffic pollution and use of fossil fuel and biomass fuel and burning of incense sticks and mosquito coils. This review provides an overview of the burden of allergic disorders in India. It appraises current evidence and justifies an urgent need for a strategic multipronged approach to enhance quality of care for allergic disorders. This may include creating an infrastructure for education and training of healthcare professionals and patients and involving regulatory authorities for making essential treatments accessible at subsidised prices. It calls for research into better phenotypic characterisation of allergic disorders, as evidence generated from high income western countries are not directly applicable to India, due to important confounders such as ethnicity, air pollution, high rates of parasitic infestation, and other infections.

Composition, physicochemical properties of pea protein and its application in functional foods

Field pea is one of the most important leguminous crops over the world. Pea protein is a relatively new type of plant proteins and has been used as a functional ingredient in global food industry. Pea protein includes four major classes (globulin, albumin, prolamin, and glutelin), in which globulin and albumin are major storage proteins in pea seeds. Globulin is soluble in salt solutions and can be further classified into legumin and vicilin. Albumin is soluble in water and regarded as metabolic and enzymatic proteins with cytosolic functions. Pea protein has a well-balanced amino acid profile with high level of lysine. The composition and structure of pea protein, as well as the processing conditions, significantly affect its physical and chemical properties, such as hydration, rheological characteristics, and surface characteristics. With its availability, low cost, nutritional values and health benefits, pea protein can be used as a novel and effective alternative to substitute for soybean or animal proteins in functional food applications.

Spectrum of Allergens and Allergen Biology in India

The growing prevalence of allergy and asthma in India has become a major health concern with symptoms ranging from mild rhinitis to severe asthma and even life-threatening anaphylaxis. The "allergen repertoire" of this subcontinent is highly diverse due to the varied climate, flora, and food habits. The proper identification, purification, and molecular characterization of allergy-eliciting molecules are essential in order to facilitate an accurate diagnosis and to design immunotherapeutic vaccines. Although several reports on prevalent allergens are available, most of these studies were based on preliminary detection and identification of the allergens. Only a few of these allergen molecules have been characterized by recombinant technology and structural biology. The present review first describes the composition, distribution pattern, and natural sources of the predominant allergens in India along with the prevalence of sensitization to these allergens across the country. We go on to present a comprehensive report on the biochemical, immunological, and molecular information on the allergens reported so far from India. The review also covers the studies on allergy- related biosafety assessment of transgenic plants. Finally, we discuss the allergen-specific immunotherapy trials performed in India.

Hypersensitivity linked to exposure of broad bean protein(s) in allergic patients and BALB/c mice

OBJECTIVE

Broad bean (Vicia faba L.), a common vegetable, belongs to the family Fabaceae and is consumed worldwide. Limited studies have been done on allergenicity of broad beans. The aim of this study was to determine if broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

METHODS

Simulated gastric fluid (SGF) assay and immunoglobulin E (IgE) immunoblotting were carried out to identify pepsin-resistant and IgE-binding proteins. The allergenicity of broad beans was assessed in allergic patients, BALB/c mice, splenocytes, and RBL-2H3 cells.

RESULTS

Eight broad bean proteins of approximate molecular weight 70, 60, 48, 32, 23, 19, 15, and 10 kDa that remained undigested in SGF, showed IgE-binding capacity as well. Of 127 allergic patients studied, broad bean allergy was evident in 16 (12%). Mice sensitized with broad bean showed increased levels of histamine, total and specific IgE, and severe signs of systemic anaphylaxis compared with controls. Enhanced levels of histamine, prostaglandin D2, cysteinyl leukotriene, and β-hexosaminidase release were observed in the primed RBL-2H3 cells following broad bean exposure. The levels of interleukin IL-4, IL-5, IL-13 and regulated on activation, normal T-cell expressed and secreted were found enhanced in broad bean-treated splenocytes culture supernatant compared with controls.

CONCLUSION

This study inferred that broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

Purification and immunobiochemical characterization of a 31 kDa cross-reactive allergen from Phaseolus vulgaris (kidney bean)

Background

Legumes are a rich source of proteins but are also potential elicitors of IgE-mediated food allergy. This study aimed to isolate and characterize a major allergen of Phaseolus vulgaris (kidney bean) and determine its allergenicity.

Methodology

Kidney bean allergen was purified using Q Sepharose column (anion exchanger) and eluates with high intensity were pooled to purify protein using Superdex 75 (gel filtration) and C₁₈ column (RP-HPLC). Patients with history of kidney bean allergy were skin prick tested (SPT) with crude kidney bean extract and the purified protein. Specific IgE was estimated in sera by enzyme-linked immunosorbent assay (ELISA). Characterization of purified protein and its cross-reactivity was investigated by immunobiochemical methods. Identification of purified protein was carried out by tandem mass spectrometry.

Principal Findings

Purified protein appeared as a single band at 31 kDa on SDS-PAGE and showed IgE binding to 88% patients’ sera by ELISA and immunoblotting. SPT with purified protein identified 78% hypersensitive patients of kidney bean. Significant release of histamine from sensitized basophils was observed after challenge with purified protein. PAS staining suggested it to be a glycoprotein, but no change in IgE binding was observed after periodate oxidation. The 31 kDa protein remained stable for 60 min on incubation with pepsin. The purified protein had high allergenic potential since it required only 102 ng of self protein for 50% IgE inhibition. Mass spectrometric analysis identified it as Phytohemagglutinin. It also showed hemagglutination with human RBCs. Cross-reactivity was observed with peanut and black gram with IC₅₀ of 185 and 228 ng respectively.

Conclusion/Significance

A 31 kDa major allergen of kidney bean was purified and identified as phytohemagglutinin with cross-reactivity to peanut and black gram.

Immediate hypersensitivity to common food allergens: an investigation on food sensitization in respiratory allergic patients of calcutta, India

Background

Food allergy may be defined as an immunoglobulin E-mediated immune response to food proteins. Such studies have previously not been done in Calcutta, India. The present study was therefore undertaken to record the sensitivity to commonly consumed foods in patients with allergic rhinitis and asthma.

Materials and methods

A survey of 800 patients (410 males and 390 females) reporting to the Allergy Unit of the Institute of Child Health, Calcutta, were selected for the study conducted from May 2006 to April 2007. Respiratory allergic patients in the age group of 5 to 60 years were evaluated using a standard questionnaire, and skin prick test was performed using common food and aeroallergens.

Results/Conclusions

Out of the 684 patients with a history of food allergy, most of them, that is, 338, are in the age group 16 to 40 years, 192 of them were in the age group 41 to 60 years, and 154 were in the age group 5 to 15 years. Most of the patients with food allergy had asthma (65.05%), rhinitis and asthma (20.03%), and skin allergies (4.97%), such as itching, eczema, and urticaria. The foodstuffs that were found to elicit symptoms of hypersensitivity were egg, milk, wheat, pulses, vegetables, fishes, and fruits.

The patients aged between 16 and 40 years (male-female ratio, 1:1.19) were mostly sensitive to prawn, brinjal, banana, ladyfinger, papaya, wheat, and egg. The age group 41 to 60 years (male-female ratio, 1:1.04) had high skin reactivity to brinjal, egg, banana, fish, and Phaseolus mungo. Patients younger than 16 years (male-female ratio, 1:1.33) were sensitized to brinjal, prawn, banana, spinach, and egg. We observed that food hypersensitivity also reflects different genetic factors and variations in cultural and dietary habits of each individual.

Food allergies in developing and emerging economies: need for comprehensive data on prevalence rates

Although much is known today about the prevalence of food allergy in the developed world, there are serious knowledge gaps about the prevalence rates of food allergy in developing countries. Food allergy affects up to 6% of children and 4% of adults. Symptoms include urticaria, gastrointestinal distress, failure to thrive, anaphylaxis and even death. There are over 170 foods known to provoke allergic reactions. Of these, the most common foods responsible for inducing 90% of reported allergic reactions are peanuts, milk, eggs, wheat, nuts (e.g., hazelnuts, walnuts, almonds, cashews, pecans, etc.), soybeans, fish, crustaceans and shellfish. Current assumptions are that prevalence rates are lower in developing countries and emerging economies such as China, Brazil and India which raises questions about potential health impacts should the assumptions not be supported by evidence. As the health and social burden of food allergy can be significant, national and international efforts focusing on food security, food safety, food quality and dietary diversity need to pay special attention to the role of food allergy in order to avoid marginalization of sub-populations in the community. More importantly, as the major food sources used in international food aid programs are frequently priority allergens (e.g., peanut, milk, eggs, soybean, fish, wheat), and due to the similarities between food allergy and some malnutrition symptoms, it will be increasingly important to understand and assess the interplay between food allergy and nutrition in order to protect and identify appropriate sources of foods for sensitized sub-populations especially in economically disadvantaged countries and communities.

Impact of thermal processing on legume allergens

Food induced allergic manifestations are reported from several parts of the world. Food proteins exert their allergenic potential by absorption through the gastrointestinal tract and can even induce life threatening anaphylaxis reactions. Among all food allergens, legume allergens play an important role in induction of allergy because legumes are a major source of protein for vegetarians. Most of the legumes are cooked either by boiling, roasting or frying before consumption, which can be considered a form of thermal treatment. Thermal processing may also include autoclaving, microwave heating, blanching, pasteurization, canning, or steaming. Thermal processing of legumes may reduce, eliminate or enhance the allergenic potential of a respective legume. In most of the cases, minimization of allergenic potential on thermal treatment has generally been reported. Thus, thermal processing can be considered an important tool by indirectly prevent allergenicity in susceptible individuals, thereby reducing treatment costs and reducing industry/office/school absence in case of working population/school going children. The present review attempts to explore various possibilities of reducing or eliminating allergenicity of leguminous food using different methods of thermal processing. Further, this review summarizes different methods of food processing, major legumes and their predominant allergenic proteins, thermal treatment and its relation with antigenicity, effect of thermal processing on legume allergens; also suggests a path that may be taken for future research to reduce the allergenicity using conventional/nonconventional methods.

Serine protease Per a 10 from Periplaneta americana bias dendritic cells towards type 2 by upregulating CD86 and low IL-12 secretions

BACKGROUND

Serine protease activity of Per a 10 from Periplaneta americana induces airway inflammation and systemic Th2 response towards self and bystander allergen.

OBJECTIVE

In the present study the effect of proteolytic activity of Per a 10 allergen on dendritic cells (DCs) polarization and consequent T cell response was investigated.

METHODS

Non-atopic subjects with no family history of asthma/allergy were recruited for the study. CD14(+) peripheral blood monocytes were purified, differentiated to immature DCs and stimulated with proteolytically active/inactivated native or recombinant Per a 10. DCs phenotype was analysed with flow cytometry and antigen presenting function assessed by co-culturing with autologous CD4(+) T cells. Cytokine levels were determined using ELISA.

RESULTS

Immature DCs differentiated into mature CD14(-)CD83(+)HLA-DR(+) cells after incubating with proteolytically active/inactivated or recombinant Per a 10. Proteolytically active Per a 10 induced significant CD86 up-regulation on DCs compared to inactivated or recombinant Per a 10 lacking enzymatic activity. Proteolytic activity of Per a 10 showed dose-dependent effect on expression of CD80, CD86, CD83, CD1a and HLA-DR. However, no significant differences were observed phenotypically in active or inactive forms except for CD86. Active Per a 10 stimulated DCs secreted significantly low IL-12 (P < 0.01) and high IL-6, compared to inactive forms of Per a 10. Naive CD4(+) T cells primed with active Per a 10 pulsed DCs also secreted significantly less IL-12 (P < 0.01) and high IL-4, IL-5 plus IL-6 (P < 0.01); in contrast to DCs pulsed with inactivated or recombinant Per a 10.

CONCLUSION AND CLINICAL RELEVANCE

Proteolytic activity of Per a 10 modulates DCs towards type 2 by CD86 up-regulation, high IL-6 and reduced IL-12 secretions. Proteolytically inactive Per a 10 can be further explored for immunotherapy.

Kidney bean: a major sensitizer among legumes in asthma and rhinitis patients from India

Background

The prevalence of IgE mediated food allergies has increased over the last two decades. Food allergy has been reported to be fatal in highly sensitive individuals. Legumes are important food allergens but their prevalence may vary among different populations. The present study identifies sensitization to common legumes among Indian population, characterizes allergens of kidney bean and establishes its cross reactivity with other legumes.

Methodology

Patients (n = 355) with history of legume allergy were skin prick tested (SPT) with 10 legumes. Specific IgE (sIgE) and total IgE were estimated in sera by enzyme-linked immunosorbent assay. Characterization of kidney bean allergens and their cross reactivity was investigated by immunobiochemical methods. Identification of major allergens of kidney bean was carried out by mass spectrometry.

Principal Findings

Kidney bean exhibited sensitization in 78 (22.0%) patients followed by chickpea 65 (18.0%) and peanut 53 (15%). SPT positive patients depicted significantly elevated sIgE levels against different legumes (r = 0.85, p<0.0001). Sera from 30 kidney bean sensitive individuals exhibited basophil histamine release (16–54%) which significantly correlated with their SPT (r = 0.83, p<0.0001) and sIgE (r = 0.99, p<0.0001). Kidney bean showed eight major allergens of 58, 50, 45, 42, 40, 37, 34 and 18 kDa on immunoblot and required 67.3±2.51 ng of homologous protein for 50% IgE inhibition. Inhibition assays revealed extensive cross reactivity among kidney bean, peanut, black gram and pigeon pea. nLC-MS/MS analysis identified four allergens of kidney bean showing significant matches with known proteins namely lectin (phytohemagglutinin), phaseolin, alpha-amylase inhibitor precursor and group 3 late embryogenesis abundant protein.

Conclusion/Significance

Among legumes, kidney bean followed by chick pea and peanut are the major allergic triggers in asthma and rhinitis patients in India. Kidney bean showed eight major allergens and cross reacted with other legumes. A combination of SPT, sIgE and histamine release assay is helpful in allergy diagnosis.

Allergenicity assessment of osmotin, a pathogenesis-related protein, used for transgenic crops

Genetic engineering can enhance abiotic stress tolerance of plants, thereby increasing productivity. The present study investigates allergenicity of osmotin protein used for developing transgenic crops. Bioinformatic analysis of osmotin was performed using SDAP and Farrp allergen databases. Osmotin was cloned in pET22b+ vector, purified to homogeneity, and analyzed for digestibility, heat stability, and IgE binding using atopic patients' sera. Osmotin showed 40-92% and 48-75% homology with allergens in SDAP and Farrp databases, respectively. These cross-reactive allergens were from apple, tomato, peach, capsicum, kiwi fruit, and cypress. Osmotin was resistant to pepsin digestion and heat treatment at 90 °C for 1 h. Osmotin protein showed dose-dependent inhibition with pooled patients' sera. It showed significant IgE binding with 22 of 117 patients' sera who were sensitized to tomato and apple, thus indicating cross-reactivity among tomato, apple, and osmotin allergens. In conclusion, osmotin was identified as a potential allergen and showed cross-reactivity with tomato and apple allergens.

Partial characterization of red gram (Cajanus cajan L. Millsp) polypeptides recognized by patients exhibiting rhinitis and bronchial asthma

We sought to assess the allergenic potential of red gram by identifying and characterizing the responsible proteins. Immunoblotting was performed to detect IgE binding proteins. Identities of these proteins were confirmed by mass spectrometry. To evaluate allergenic potential, BALB/c mice were sensitized with red gram proteins and levels of specific immunoglobulins, histamine, Th2 cytokines were measured. Allergenic response was evident by significant increase in specific IgE, IgG1, histamine and Th2 cytokine levels. Prominent anaphylactic symptoms, discernible histopathological responses and down regulation of IFN-gamma levels give strong support towards allergenicity of red gram proteins. IgE immunoblot detected five proteins; one of 66 kDa, three of 45 kDa (pI of approximately 5.3, 5.9 and 6.6) and one of 30 kDa. All these proteins showed homology to known allergens of soybean (different subunits of beta-conglycinin), lentil (Len c1 and Len c2), peanut (Ara h1) and pea (vicilin). In conclusion, five novel IgE binding proteins (namely Caj c1, Caj c2, Caj c3, Caj c4 and Caj c5) were identified as putative clinically relevant allergens.

Current immunological approaches for management of allergic rhinitis and bronchial asthma

A large population world over is affected with allergic diseases and asthma. Pharmacotherapy for allergic diseases and asthma is effective in controlling symptoms but on discontinuation of medication, symptoms reoccur. In contrast, immunotherapy modifies and corrects the underlying pathological immune responses in an antigen-specific manner. Immunotherapy shows an increase in IgG (blocking antibody) that competes with IgE for allergen, inhibiting the release of inflammatory mediators. Recent studies suggest that immunotherapy acts by modifying CD4+ T-cell responses either by immune deviation, T-cell anergy and/or both. Current immunological approaches for management of allergies and asthma involve immunization with native allergen, modified allergen, peptides/cDNA of allergen, anti-IgE, adjuvants coupled allergen, including immunostimulatory DNA sequences, cytokines, and bacterial products. These approaches modulate the immune response and are intended to give long-term benefit.

Prevalence of legume sensitization in patients with naso-bronchial allergy

Prevalence of legume allergy and concomitant sensitization to different allergens was evaluated in patients of asthma and/ or rhinitis. Skin prick test with 27 common food allergens and 61 aeroallergens in 76 subjects was performed. Out of 76 subjects, 41 perceived allergenic problems with different food items as contributing factor. Only six patients showed prick test positivity compatible with their anamnesis. However, 35 subjects showed sensitization to different food items, out of which thirty were sensitive to legumes. The common foods in decreasing order of allergenicity were chickpea, followed by green gram, egg white, and bean fresh/red gram. Concomitant sensitization to different legume crops was found in patients.

Increased expression of tissue vascular endothelial growth factor and foetal liver kinase-1 receptor in seasonal allergic rhinitis and relevance to asthma component

BACKGROUND

There is a difference in the extent of remodelling in allergic rhinitis (AR) and asthma. This may be attributed to the difference in local tissue response to these mediators.

OBJECTIVES

The aim of this study was to compare vascular endothelial growth factor (VEGF) and its receptor foetal liver kinase (Flk)-1 expression between seasonal AR patients with or without asthma and non-allergic controls as well as that between AR patients with and without asthma.

METHODS

Thirteen subjects with seasonal AR and six non-allergic controls were included in the study. Allergic sensitization was demonstrated by a skin prick test. Inferior turbinate thiny biopsies were obtained from both groups. Monoclonal mouse antibodies were used to demonstrate VEGF and Flk-1. Nasal mucosal endothelial cells' staining intensity was graded semi-quantitatively and the histochemical score (HSCORE) was calculated. In all samples, VEGF- and Flk-1-labelled vessels were counted for the assessment of vascular surface density (VSD).

RESULTS

The mean HSCORE for VEGF and anti-VEGF-based VSD were significantly higher in the patient group (P=0.001 and 0.002, respectively). The mean HSCORE for Flk-1 and anti-Flk-1-based VSD in the patient group were significantly higher than those in the control group (P=0.016 and 0.028, respectively). Differences between the mean HSCORE for VEGF and anti-VEGF-based VSD in patients with pure AR and AR and asthma were insignificant (P=0.16 and 0.39, respectively). The mean HSCORE for Flk-1 and anti-Flk-1-based VSD in patients with pure AR were significantly lower than those in patients with AR and asthma (P=0.004 and 0.018, respectively).

CONCLUSION

Angiogenic factor VEGF and its receptor Flk-1 is increased in AR. A similar increase in VEGF in AR with and without asthma despite a higher Flk-1 in AR patients with asthma may be a possible explanation for the presence of angiogenesis in the airway wall in patients with asthma but not in those with pure AR.

Immunoglobulin E (IgE)-mediated cross-reactivity between mesquite pollen proteins and lima bean, an edible legume

Immunoglobulin E (IgE)-mediated food allergy often develops as a consequence of allergic sensitization to pollen proteins. Mesquite (Prosopis juliflora) tree pollen is reported to be cross-reactive with other pollen species, but little has been reported on its cross-reactivity with plant-derived foods belonging to the same/different families. The present study investigates the in vitro cross-reactivity of mesquite pollen and lima bean (Phaseolus lunatus), an edible seed belonging to the Leguminosae family. Of 110 patients (asthma, rhinitis or both) tested intradermally, 20 showed marked positive reactions with Prosopis pollen extract. Of these, 12 patients showed elevated specific IgE to Prosopis pollen extract alone and four to both Phaseolus and pollen extract. In vitro cross-reactivity was investigated using inhibition assays [enzyme-linked immunosorbent assay (ELISA) inhibition, immunoblot inhibition], histamine release and lymphoproliferation. P. lunatus extract could inhibit IgE binding to P. juliflora in a dose-dependent manner, requiring 400 ng of protein for 50% inhibition in ELISA assay. Immunoblot and immunoblot inhibition demonstrated the presence of 20, 26, 35, 66 and 72 kDa as shared IgE binding components between the two extracts. Histamine release, peripheral blood mononuclear cells proliferation and interleukin (IL)-4 levels also suggested allergenic cross-reactivity. In conclusion, there is humoral and cellular cross-reactivity between Prosopis pollen and Phaseolus seed allergens.

Bronchial asthma: the Indian scene

PURPOSE OF REVIEW

Although asthma is a global disease, there are important differences in epidemiology, clinical spectrum and management practices in India. Some of these issues have been reviewed in this article.

RECENT FINDINGS

The prevalence of 'ever asthma' was reported in 2.4% in a population study on 73,605 individuals conducted simultaneously at four major centres in India with the use of a single definition and uniform methodology employing a validated questionnaire. Of the several risk factors which were found to be significant, exposure to environmental tobacco smoke during childhood alone or both during childhood and adulthood was important in the development of and in increasing morbidity from asthma. Many other triggers and risk factors which include local aeroallergens and air pollutants have been identified. Allergic bronchopulmonary aspergillosis is an important cause of difficult to treat asthma and almost half of these patients receive antitubercular treatment at some stage. Simplified consensus guidelines based on international guidelines and local practices have been developed for use at the primary and secondary levels of healthcare.

SUMMARY

The prevalence of asthma in India is somewhat similar to that seen in other Asian countries. Consensus management guidelines adapted from standard international guidelines adequately address the local concerns and issues.