Improved Sensitivity of Allergen Detection by Immunoaffinity LC-MS/MS Using Ovalbumin as a Case Study

Food allergies are caused by severe hypersensitivity to specific food allergens such as the egg protein ovalbumin. It is therefore important to test food products for the presence of allergens to protect allergic people from accidental ingestion. For egg detection, ELISA is the only reasonable commercially available test format, although the recognition of target allergens can be affected by food processing, which may lead to false negative results. Current mass spectrometry-based detection methods may overcome this issue, but these approaches are often less sensitive. Here we combined the advantages of antibody-based and MS-based methods by developing an immunoaffinity LC-MS/MS technique to detect the common egg allergen Gal d 2. We investigated the principal functionality of this method with incurred cookie material containing whole egg powder. We found that the new method matched easily the sensitivity of egg specific ELISA tests. Further western blot experiments indicated that this strategy may be unaffected by food processing, providing an important alternative strategy for the detection and quantification of allergens in food.

Clinical Characteristics and Allergen Detection of Perioperative Anaphylaxis: A 12-year Retrospective Analysis from an Anesthesia Clinic in China

Background: Anaphylaxis during anesthesia is a rare but often a potentially life-threatening event for patients. Identifying culprit agents responsible for anaphylaxis is of great important for avoiding potential re-exposure to allergens, but it poses great challenge for anesthetists. This retrospective study aimed to analyze the culprits of patients with a history of perioperative anaphylaxis referred to an anesthesia allergy clinic in China, and to evaluate the role of allergy diagnostic tests in clinical practice.Methods: A total of 145 patients (102 female/43 male) who attended the Anesthesia Allergy Clinic for allergen detection between 1 January 2009 and 31 December 2020 were reviewed retrospectively. Clinical characteristics, results of allergy diagnostic tests including skin and/or basophil activation tests, and the incidence of repeat anaphylaxis after use of recommended alternative anesthetics were obtained.Results: Of these 145 patients, 109 patients (75.2%, 74 females/35 males) were determined to experience perioperative anaphylaxis. The commonest presenting clinical feature was cardiovascular manifestations (n=63, 57.8%). According to diagnostic work up, the commonest culprits for perioperative anaphylaxis were neuromuscular blocking agents (n= 35, 32.1%). After diagnostic work up, 52 patients underwent repeat anesthesia, and none had recurrent anaphylaxis.Conclusions: This study suggests that neuromuscular blocking agents are the main culprits for perioperative anaphylaxis. For patients with perioperative anaphylaxis, allergy diagnostic tests are essential to identify causative agents, and to find suitable alternative drugs for the planning of repeat anesthesia.

Rapid and accurate electrochemical sensor for food allergen detection in complex foods

Food allergies are estimated to affect about 2–5% of adults and 6–8% of children, globally. Currently, the most effective strategy for food allergy management is stringent avoidance of the offending allergen. Unlike other major food allergens, soy is uniquely challenging to avoid due to its prevalence and insidiousness in a wide variety of foods, such as infant formulas. Recently, we demonstrated a simple, accurate, and consumer-friendly sensor using molecularly imprinted polymers (MIPs) for rapid detection of soy allergenic tracers in complex food matrices at clinically relevant levels. In this work, we build on these findings by subjecting MIP-based soy allergen sensors to test trials in 42 different food products, representing over 300 ingredients. Foods were selected based on their compositional complexity to capture a wide range of preparatory methods and processing conditions. In each case, the Allergy Amulet correctly reported on the presence or absence of soy allergen tracer in investigated samples and were subjected to immunoassay confirmatory analysis. The outcome of this research will help resolve persistent difficulties with commercial technologies in detecting allergenic tracers with minimal cross-interference in foods, and will give those with soy allergies the ability to easily, rapidly, and accurately identify and avoid foods with soy allergens.

NIgPred: Class-Specific Antibody Prediction for Linear B-Cell Epitopes Based on Heterogeneous Features and Machine-Learning Approaches

Upon invasion by foreign pathogens, specific antibodies can identify specific foreign antigens and disable them. As a result of this ability, antibodies can help with vaccine production and food allergen detection in patients. Many studies have focused on predicting linear B-cell epitopes, but only two prediction tools are currently available to predict the sub-type of an epitope. NIgPred was developed as a prediction tool for IgA, IgE, and IgG. NIgPred integrates various heterologous features with machine-learning approaches. Differently from previous studies, our study considered peptide-characteristic correlation and autocorrelation features. Sixty kinds of classifier were applied to construct the best prediction model. Furthermore, the genetic algorithm and hill-climbing algorithm were used to select the most suitable features for improving the accuracy and reducing the time complexity of the training model. NIgPred was found to be superior to the currently available tools for predicting IgE epitopes and IgG epitopes on independent test sets. Moreover, NIgPred achieved a prediction accuracy of 100% for the IgG epitopes of a coronavirus data set. NIgPred is publicly available at our website.

Serum allergen spectrum and prevalence of allergic disease in Shenzhen, China

Purpose: Allergen sensitization are common allergic diseases worldwide, with widely varying estimates of prevalence in the population. The characteristics and prevalence of allergens and diseases in Shenzhen. Patients and methods: Allergen-specific IgE results were investigated among 20483 subjects from January 2016 to June 2020 based on by Western blotting, and statistical analysis was performed on sIgE and related diseases in patients with different ages, genders, months, mixed allergens and grade. Results: Among 20483 subjects, 13149 (64.19%) were clinically positive for at least single allergen. Single allergen positive rate (35.42%), double allergen positive rate (23.96%), triple allergen positive rate (16.04%). The positive rate of sIgE in male was higher than that in female (69.15% and 60. 02% respectively, P<0.01). Allergen detection rate varies with age (P<0.05). The cumulative positive results were 35083, grade 1: 16705 items, 47.61%; grade 2: 8003 items, 22.81%; grade 5: 3840 items, 10.94%. The positive rate of sIgE in March was the highest (82.20%), which was statistically significant compared with other months (P<0.05). The probability of cockroach allergen causing atopic dermatitis/urticaria was 67%, and asthma in just 4%. Conclusion: Our findings reveal that the positive rate of allergens was high in Shenzhen. Dust mite was the main allergen. There were differences in age, gender and month, and the probability of allergic diseases such as atopic dermatitis/urticaria aznd rhinitis/sinusitis is high.