Multiple protein extract microarray for profiling human food-specific immunoglobulins A, M, G and E

Microarray molecular mapping of horses with severe asthma

BACKGROUND

Severe asthma (SA) in horses, resembling human asthma, is a prevalent, debilitating allergic respiratory condition marked by elevated allergen-specific immunoglobulin E (IgE) against environmental proteins; however, research exploring the exposome's influence on IgE profiles is currently limited but holds paramount significance for diagnostic and therapeutic developments.

ANIMALS

Thirty-five sports horses were analyzed, consisting of environmentally matched samples from France (5 SA; 6 control), the United States (6 SA; 6 control), and Canada (6 SEA; 6 control).

METHODS

This intentional cross-sectional study investigated the sensitization profiles of SA-affected and healthy horses via serological antigen microarray profiling. Partial least square-discriminant analysis (PLS-DA) was used to identify and rank the importance of allergens for class separation (ie, affected/non-affected) as variable influence of projection (VIP), and allergen with commonality internationally established via frequency analysis.

RESULTS

PLS-DA models showed high discriminatory power in predicting SA in horses from Canada (area under the curve [AUC] 0.995) and France (AUC 0.867) but poor discriminatory power in horses from the United States (AUC 0.38). Hev b 5.0101, Cyn D, Der p 2, and Rum cr were the only shared allergens across all geographical groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

Microarray profiling can identify specific allergenic components associated with SA in horses, while mathematical modeling of this data can be used for disease classification, highlighting the variability of sensitization profiles between geographical locations and emphasizing the importance of local exposure to the prevalence of different allergens. Frequency scoring analysis can identify important variables that contribute to the classification of SA across different geographical regions.

Evolution Toward Chip-Based Arrays in the Laboratory Diagnosis of Human Allergic Disease

Multiplex-based specific IgE antibody assays have emerged into the clinical immunology laboratory through the combined use of pure, recombinant allergenic molecules and new methods to simultaneously and accurately analyze specific IgE antibodies to hundreds of allergens. This review traces the historical development and examines outstanding questions related to the strengths and limitations of these new molecular allergen multipex technologies for the assessment of human allergic sensitization. Multiplexed technologies are poised to provide the most cost-effective and comprehensive evaluation of patients with suspected allergy as compared with the commonly used singleplex autoanalyzers. How analytically sensitive and quantitative are the multiplex technologies, down to 0.1 kUA/L? Because each allergen is viewed as a unique assay, how will analytical and clinical performance be documented at the manufacturing and clinical laboratory levels to guarantee reproducibility and obtain government regulatory clearance? Will interference by naturally occurring allergen-specific IgG compromise analytical performance? Successful resolution of these and other questions covered in this review will position multiplex technologies to become the single most-effective means of screening patients for allergic sensitization, assessing IgE antibody cross-reactivity, and planning therapy directed at the patient with allergy.

Reversed-phase allergen microarrays on optical discs for multiplexed diagnostics of food allergies

A high percentage of the population suffers from multiple food allergies justifying  the importance of reliable diagnostic methods. Single-analyte solutions based on the determination of specific immunoglobulins E (sIgE) are safe and fast but are generally time-consuming and expensive. Thus sustainable microanalytical methods that provide multianalyte profiling information are highly demanded. This work presents the in vitro biosensing of specific IgE levels based on a reversed-phase allergen array. The approach consists of optical biosensing supported by direct multiplex immunoassays and on-disc technology. It identifies 12 sIgE associated with food allergies in a single analysis with a low serum sample volume (25 µL). After processing captured images, specific signals for each target biomarker correlate to their concentration. The assay analytically performs well with 0.3 IU/mL and 0.41 IU/mL as the detection and quantification limits in serum, respectively. This novel method achieves excellent clinical specificity (100%) and high sensitivity (91.1%), considering the diagnosis obtained by clinical history and ImmunoCAP analysis. The results demonstrate that microanalytical systems based on allergen arrays can potentially diagnose multiple food allergies and are easily implemented in primary care laboratory settings.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Development of a protein microarray-based diagnostic chip mimicking the skin prick test for allergy diagnosis

Protein microarrays have been successfully used for detection of allergen-specific IgE in patient sera. Here, we demonstrate proof-of-concept of a solid-phase technique coupling the high-throughput potential of protein microarrays with the biologically relevant readout provided by IgE reporter cells, creating a novel allergic sensitization detection system. Three proteins (κ-casein, timothy grass pollen extract, polyclonal anti-human IgE) were printed onto three different polymer-coated surfaces (aldehyde-, epoxy- and NHS ester-coated). ToF-SIMs analysis was performed to assess printed protein stability and retention during washing steps. NFAT-DsRed rat basophil leukemia cell attachment and retention during washing steps was assessed after treatment with various extracellular matrix proteins. NFAT-DsRed IgE reporter cells were sensitized with serum of an allergic donor, incubated on the printed slides, and cell activation determined using a microarray laser scanner. NFAT DsRed IgE reporter cell binding was significantly increased on all polymer surfaces after incubation with fibronectin and vitronectin, but not collagen or laminin. All surfaces supported printed protein stability during washing procedure, with epoxy- and NHS ester-coated surfaces showing best protein retention. Cell activation was significantly higher in NHS ester-coated slides after timothy grass pollen extract stimulation appearing a suitable substrate for further development of an automated allergy diagnosis system.

Antigen array for serological diagnosis and novel allergen identification in severe equine asthma

Severe equine asthma (sEA), which closely resembles human asthma, is a debilitating and performance-limiting allergic respiratory disorder which affects 14% of horses in the Northern Hemisphere and is associated with increased allergen-specific immunoglobulin E (IgE) against a range of environmental proteins. A comprehensive microarray platform was developed to enable the simultaneous detection of allergen-specific equine IgE in serum against a wide range of putative allergenic proteins. The microarray revealed a plethora of novel pollen, bacteria, mould and arthropod proteins significant in the aetiology of sEA. Moreover, the analyses revealed an association between sEA-affected horses and IgE antibodies specific for proteins derived from latex, which has traditionally been ubiquitous to the horse’s environment in the form of riding surfaces and race tracks. Further work is required to establish the involvement of latex proteins in sEA as a potential risk factor. This work demonstrates a novel and rapid approach to sEA diagnosis, providing a platform for tailored management and the development of allergen-specific immunotherapy.

Development of a comprehensive protein microarray for immunoglobulin E profiling in horses with severe asthma

BACKGROUND

Severe asthma in horses, known as severe equine asthma (SEA), is a prevalent, performance-limiting disease associated with increased allergen-specific immunoglobulin E (IgE) against a range of environmental aeroallergens.

OBJECTIVE

To develop a protein microarray platform to profile IgE against a range of proven and novel environmental proteins in SEA-affected horses.

ANIMALS

Six SEA-affected and 6 clinically healthy Warmblood performance horses.

METHODS

Developed a protein microarray (n = 384) using protein extracts and purified proteins from a large number of families including pollen, bacteria, fungi, and arthropods associated with the horses, environment. Conditions were optimized and assessed for printing, incubation, immunolabeling, biological fluid source, concentration techniques, reproducibility, and specificity.

RESULTS

This method identified a number of novel allergens, while also identifying an association between SEA and pollen sensitization. Immunolabeling methods confirmed the accuracy of a commercially available mouse anti-horse IgE 3H10 source (R2 = 0.91). Biological fluid source evaluation indicated that sera and bronchoalveolar lavage fluid (BALF) yielded the same specific IgE profile (average R2 = 0.75). Amicon centrifugal filters were found to be the most efficient technique for concentrating BALF for IgE analysis at 40-fold. Overnight incubation maintained the same sensitization profile while increasing sensitivity. Reproducibility was demonstrated (R2 = 0.97), as was specificity using protein inhibition assays. Arthropods, fungi, and pollens showed the greatest discrimination for SEA.

CONCLUSIONS AND CLINICAL IMPORTANCE

We have established that protein microarrays can be used for large-scale IgE mapping of allergens associated with the environment of horses. This technology provides a sound platform for specific diagnosis, management, and treatment of SEA.

Development of a Multiplex Glycan Microarray Assay and Comparative Analysis of Human Serum Anti-Glycan IgA, IgG, and IgM Repertoires

Serum antibodies that recognize carbohydrate antigens play a fundamental role in immune defense, homeostasis, and autoimmunity. In addition, they serve as potential biomarkers for a variety of medical applications. For most anti-glycan antibodies found in human serum, however, the origins, regulation, and biological significance are not well understood. Antibody subpopulations that are relevant to a particular biological process or disease are often difficult to identify from the myriad of anti-glycan antibodies present in human serum. While prior studies have examined anti-glycan IgG and/or IgM repertoires, little is known about IgA repertoires or how IgA, IgG, and IgM are related. In this study, we describe the development of a multiplex assay to simultaneously detect IgA, IgG, and IgM on a glycan microarray and its application to studying anti-glycan repertoires in healthy subjects. The multiplex glycan microarray assay revealed unique insights and systems-level relationships that would be difficult to uncover using traditional approaches. In particular, we found that anti-glycan IgA, IgG, and IgM expression levels appear to be tightly regulated, coordinated within individuals, and stable over time. Additionally, our results help define natural fluctuations over time, which is critical for identifying changes that are beyond normal biological variation.

Microarray Technology Applied to Human Allergic Disease

IgE antibodies serve as the gatekeeper for the release of mediators from sensitized (IgE positive) mast cells and basophils following a relevant allergen exposure which can lead to an immediate-type hypersensitivity (allergic) reaction. Purified recombinant and native allergens were combined in the 1990s with state of the art chip technology to establish the first microarray-based IgE antibody assay. Triplicate spots to over 100 allergenic molecules are immobilized on an amine-activated glass slide to form a single panel multi-allergosorbent assay. Human antibodies, typically of the IgE and IgG isotypes, specific for one or many allergens bind to their respective allergen(s) on the chip. Following removal of unbound serum proteins, bound IgE antibody is detected with a fluorophore-labeled anti-human IgE reagent. The fluorescent profile from the completed slide provides a sensitization profile of an allergic patient which can identify IgE antibodies that bind to structurally similar (cross-reactive) allergen families versus molecules that are unique to a single allergen specificity. Despite its ability to rapidly analyze many IgE antibody specificities in a single simple assay format, the chip-based microarray remains less analytically sensitive and quantitative than its singleplex assay counterpart (ImmunoCAP, Immulite). Microgram per mL quantities of allergen-specific IgG antibody can also complete with nanogram per mL quantities of specific IgE for limited allergen binding sites on the chip. Microarray assays, while not used in clinical immunology laboratories for routine patient IgE antibody testing, will remain an excellent research tool for defining sensitization profiles of populations in epidemiological studies.

Development of a microarray-based method for allergen-specific IgE and IgG4 detection

Background

sIgE and sIgG4 detection is necessary for more accurate and effective type I hypersensitivity diagnostics and the estimation of disease development. Typically, the analyses of these antibodies are performed separately with the help of various specialized systems. The aim of this study was to develop a microarray-based method for the simultaneous quantitative detection of sIgE and sIgG4 to the most common allergens in a single sample.

Methods

A quantitative method for the simultaneous detection of sIgE and sIgG4 was developed based on the technology of hydrogel microchips previously designed at Engelhardt Institute of Molecular Biology, Russian Academy of Sciences (EIMB RAS). The microarray contained gel pads with immobilized allergens and gel pads that allow for the obtaining of sIgE and sIgG4 internal calibration curves for each allergen during the assay. The possibility of the simultaneous detection of sIgE and sIgG4 was developed using the corresponding Cy5 and Cy3 fluorescent dyes.

Results

The multiplex immunoassay method using hydrogel microarrays developed in this study allowed the quantitative detection of sIgE and sIgG4 to 31 allergens from different groups in a single assay. A comparison of the microarray with the existing plate-based analogues (i.e., ALLERG-O-LIQ and sIgG4 ELISA) was performed by analysing 152 blood serum samples and by evaluating Pearson correlation coefficients, ROC analysis, and Passing-Bablok linear regression results.

Conclusion

The implementation of this method in allergy diagnostics will provide the possibility of simultaneously performing primary patient screening and obtaining additional information concerning the severity of the allergies and the choice of an appropriate therapy.

Protein Microarray-Based IgE Immunoassay for Allergy Diagnosis

Protein microarray is a miniaturized multi-analyte, solid-phased immunoassay where thousands of immobilized individual protein spots on a microscopic slide bind are bound to specific antibodies (immunoglobulins) from serum samples, which are then detected by fluorescent labeling. The image processing and pattern recognition are then quantitatively analyzed using advanced algorithms. Here, we describe the use of an in-house-produced complex protein microarray containing extracts and pure proteins that has been probed with antibodies present in the horse sera and detection by fluorophore-conjugated antibody and data analysis. The flexibility of the number and types of proteins that can be printed on the microarray allows different set of specific IgE immunoassay analysis to be carried out.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Use of humanized rat basophilic leukemia reporter cell lines as a diagnostic tool for detection of allergen-specific IgE in allergic patients: time for a reappraisal?

The interaction between allergens and specific IgE is at the heart of the allergic response and as such lies at the center of techniques used for diagnosis of allergic sensitization. Although serological tests are available, in vivo tests such as double-blind placebo-controlled food challenges (DBPCFC) and skin prick test (SPT) associated to the patients' clinical history are still the main guides to clinicians in many practices around the world. More recently, complex protein arrays and basophil activation tests, requiring only small amounts of whole blood, have been developed and refined, but are yet to enter clinical practice. Similarly, the use of rat basophilic leukemia (RBL) cell lines for detection of allergen-specific IgE has been made possible by stable transfection of the human FcεRI α chain into this cell line more than 20 years ago, but has not found widespread acceptance among clinicians. Here, we review the perceived limitations of diagnostic applications of humanized RBL systems. Furthermore, we illustrate how the introduction of reporter genes into humanized RBL cells is able to overcome most of these limitations, and has the potential to become a new powerful tool to complement the armamentarium of allergists. A demonstration of the usefulness of humanized RBL reporter systems for elucidation of complex IgE sensitization patterns against wheat proteins and a section on the use of fluorescence-based reporter systems in combination with allergen arrays close the review.

Novel in vitro diagnosis of equine allergies using a protein array and mathematical modelling approach: a proof of concept using insect bite hypersensitivity

Insect bite hypersensitivity (IBH) is a seasonal recurrent skin allergy of horses caused by IgE-mediated reactions to allergens present in the saliva of biting insects of the genus Culicoides, and possibly also Simulium and Stomoxys species. In this work we show that protein microarrays containing complex extracts and pure proteins, including recombinant Culicoides allergens, can be used as a powerful technique for the diagnosis of IBH. Besides the obvious advantages such as general profiling and use of few microliters of samples, this microarray technique permits automation and allows the generation of mathematical models with the calculation of individual risk profiles that can support the clinical diagnosis of allergic diseases. After selection of variables on influence on the projection (VIP), the observed values of sensitivity and specificity were 1.0 and 0.967, respectively. This confirms the highly discriminatory power of this approach for IBH and made it possible to attain a robust predictive mathematical model for this disease. It also further demonstrates the specificity of the protein array method on identifying a particular IgE-mediated disease when the sensitising allergen group is known.

Optimisation and use of humanised RBL NF-AT-GFP and NF-AT-DsRed reporter cell lines suitable for high-throughput scale detection of allergic sensitisation in array format and identification of the ECM-integrin interaction as critical factor

We have previously described a microarray platform combining live basophils with protein arrays suitable for high-throughput detection of sensitisation against allergens. During optimisation of this technique, we observed severe losses of adhering cells during the washing steps, particularly after activation. In order to preserve cell binding, we tested the cell adhesion characteristics of different extracellular matrix proteins: human collagen I, fibronectin (FN) from bovine plasma and laminin (LN). FN was more effective than LN and collagen. Cell detachment after activation was in part due to reduced surface expression of VLA-4, the main ligand for FN, which was significantly decreased within 15 min of stimulation with 1 μg/mL calcium ionophore A23187, reaching a minimum after 2 h then slowly recovering. These optimised conditions were used for testing of well-characterised sera from allergic patients using two newly developed rat basophil leukaemia stable reporter cell lines (RBL NF-AT/GFP and RBL NF-AT/DsRed), which both express the human high-affinity IgE receptor alpha chain (FcεRIα). Both cell lines were able to detect sensitisation to specific allergens showing the expected bell-shaped dose–response curve, and correlated (R² = 0.75) with the standard beta-hexosaminidase assay, which is not suitable for an array format.

Tus-Ter-lock immuno-PCR assays for the sensitive detection of tropomyosin-specific IgE antibodies

BACKGROUND

The increasing prevalence of food allergies requires development of specific and sensitive tests capable of identifying the allergen responsible for the disease. The development of serologic tests that can detect specific IgE antibodies to allergenic proteins would, therefore, be highly received.

RESULTS

Here we present two new quantitative immuno-PCR assays for the sensitive detection of antibodies specific to the shrimp allergen tropomyosin. Both assays are based on the self-assembling Tus-Ter-lock protein-DNA conjugation system. Significantly elevated levels of tropomyosin-specific IgE were detected in sera from patients allergic to shrimp.

CONCLUSION

This is the first time an allergenic protein has been fused with Tus to enable specific IgE antibody detection in human sera by quantitative immuno-PCR.

Quantifying antibody binding on protein microarrays using microarray nonlinear calibration

We present a microarray nonlinear calibration (MiNC) method for quantifying antibody binding to the surface of protein microarrays that significantly increases the linear dynamic range and reduces assay variation compared with traditional approaches. A serological analysis of guinea pig Mycobacterium tuberculosis models showed that a larger number of putative antigen targets were identified with MiNC, which is consistent with the improved assay performance of protein microarrays. MiNC has the potential to be employed in biomedical research using multiplex antibody assays that need quantitation, including the discovery of antibody biomarkers, clinical diagnostics with multi-antibody signatures, and construction of immune mathematical models.

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-being.

The added value of allergen microarray technique to the management of poly-sensitized allergic patients

PURPOSE OF REVIEW

To evaluate the relevance of results obtained using allergen microarray technique for the description of the IgE repertoire in allergic patients.

RECENT FINDINGS

Allergen microarray was introduced at the beginning of the last decade. Since then, an increasing number of allergens have been identified, correspondingly increasing the accuracy of the description of immunoglobulin (Ig)E repertoire. In the last 2 years, a large number of articles were published that accurately described not only the general features of this technique, but also the use of allergen microarray in specific situations.

SUMMARY

The recent availability of highly purified or recombinant allergen components has deeply modified the laboratory approach to allergy diagnosis that, now, it cannot be limited to the detection of IgE specific to extractive allergens. Indeed, these contain both specific components (i.e. molecules strictly associated to that allergen source) and pan-allergen or cross-reacting allergens (i.e. molecules that are present in different similar allergen sources or that are present in highly homologous structures in different species). Newer techniques such as recombinant allergen testing and allergen microarray allow a more detailed evaluation of IgE responses. Future research is needed to more clearly define their role in clinical practice.

Beyond skin testing: state of the art and new horizons in food allergy diagnostic testing

Food allergy affects approximately 1% to 10.8% of the general population, and its prevalence seems to be increasing. An accurate diagnosis is particularly important because a misdiagnosis could lead to life-threatening reactions or to unnecessary restrictive diets. However, allergy tests currently used in clinical practice have limited accuracy, and an oral food challenge, considered as the gold standard, is often required to confirm or exclude a food allergy. This article reviews several promising novel approaches for the diagnosis of food allergy, such as new molecular diagnostic technologies and functional assays, along with their potential clinical applications.

Prediction of tolerance in children with IgE mediated cow's milk allergy by microarray profiling and chemometric approach

The sera of a retrospective cohort (n=41) composed of children with well characterized cow's milk allergy collected from multiple visits were analyzed using a protein microarray system measuring four classes of immunoglobulins. The frequency of the visits, age and gender distribution reflected real situation faced by the clinicians at a pediatric reference center for food allergy in São Paulo, Brazil. The profiling array results have shown that total IgG and IgA share similar specificity whilst IgM and in particular IgE are distantly related. The correlation of specificity of IgE and IgA is variable amongst the patients and this relationship cannot be used to predict atopy or the onset of tolerance to milk. The array profiling technique has corroborated the clinical selection criteria for this cohort albeit it clearly suggested that 4 out of the 41 patients might have allergies other than milk origin. There was also a good correlation between the array data and ImmunoCAP results, casein in particular. By using qualitative and quantitative multivariate analysis routines it was possible to produce validated statistical models to predict with reasonable accuracy the onset of tolerance to milk proteins. If expanded to larger study groups, the array profiling in combination with the multivariate techniques show potential to improve the prognostic of milk allergic patients.

Ber e 1 protein: the versatile major allergen from Brazil nut seeds

Due mainly to its extremely high content of sulphur amino acids, Ber e 1 protein, the major allergen from Brazil nut, has attracted much scientific and press attention. Ber e 1 was the main target protein in early biotechnology transgenic work, in early processing studies of plant storage proteins, in plant vacuolar targeting studies and as the main protein in early nutritional supplementation experiments. Ber e 1 was also one of the first food allergens to be unintentionally transferred from one plant to another and was involved in the first reported case of systemic allergic reaction caused by a food allergen transferred in semen. In this review, many of the Ber e 1 unique biotechnological and structural functions are discussed with a particular emphasis on its use as model protein for studies of intrinsic allergenicity of food proteins.

Microarray of allergenic component-based diagnosis in food allergy

PURPOSE OF REVIEW

The determination of specific IgE (sIgE) against allergenic components fixed in a solid support that is provided as a microarray of high capacity and allows a more precise evaluation in the food allergy diagnosis. In this review, we will analyze the results obtained to date with this technology applied to the component-based diagnosis of food allergy.

RECENT FINDINGS

Microarrays of proteins or glycoproteins allow us to know the profile of sensitization of a patient with food allergy. At present, a commercially available technique exists which allows sIgE to be detected against 103 allergenic molecules. Several laboratories worldwide have explored and optimized this technique for few allergen extracts and the results have been promising with high reliabilities and sensitivities and above all, good correlations with previous existing conventional assays.

SUMMARY

In recent years, as a result of advances in molecular biology, together with the development of new technologies of producing high-capacity solid-phase matrices such as microarrays, the diagnosis of food allergy has improved and the basic situation of analyzing sIgE against an allergenic source has now become real the possibility of analyzing sIgE against an allergenic protein or glycoprotein. This change has not only led to a more precise diagnosis of sensitization, but can also be used to explain the different hazards of certain molecular sensitizations, crossreactivity phenomena in many cases and can even change the clinical management according to the information provided. Further studies are clearly needed to evaluate more precisely the scope of this new technique.

Microarrayed recombinant allergens for diagnostic testing

The development of protein microarray-based immunoassays and the availability of recombinant allergens have, to a significant extent, emerged together over the past decade. Their long-anticipated wider application to allergy diagnosis has recently begun to accelerate. This review discusses some of the strengths and weaknesses of molecularly defined allergy testing and the microarray platform. Several recent applications of microarray assays to allergy testing are also summarized. Promising findings, particularly in the context of food and latex allergy, point to the potential for greater resolution between clinical reactivity and asymptomatic sensitization with this platform.