Allergy (and clinical immunology)

Urine Mast Cell Mediator Levels in the Pediatric Population with and without Allergic Disease Stratified by Age and Gender: A Novel Diagnostic Insight

You might not be allergic to penicillin after all.

Our researchers from The Peter Doherty Institute for Infection and Immunity, along with Austin Health, are part of a global study showing that simple testing can safely rule out incorrect allergy labels, helping patients access more effective antibiotics and improving care worldwide.

We sat down with Professor Jason Trubiano from the Faculty of Medicine, Dentistry and Health Sciences to unpack what this means for patients and healthcare systems.

Explore the research → unimelb.me/3Qf1nNZ

Allergy Season Meets a Scientific Breakthrough

Every spring, millions of people brace themselves for the return of pollen. But a recent discovery could change the game: our bodies may store memories of microbial exposure directly within lung tissues, opening the door to long-lasting prevention of allergies.

Our teams have revealed that protection against allergies is stored not in immune cells, but in lung fibroblasts — structural cells that "remember" microbial exposure through epigenetic changes, shielding us from allergic reactions for months.

This finding resonates deeply with my work on microbe-immune interactions and our strategic plan Pasteur 2030. It shows how profoundly microbes educate our bodies in ways we're only beginning to understand.

What excites me? The clinical implications.
This opens a path toward genuine prevention. Not just treating allergies but stopping them before they develop through early interventions that reprogram tissue memory.

This is fundamental research at its finest: curiosity-driven science that unlocks unexpected therapeutic possibilities. And it showcases the power of interdisciplinary collaboration that defines Institut Pasteur — immunologists and tissue biologists working together to solve complex questions.

Warmest congratulations to Gérard Eberl, Lucie Peduto and all the researchers involved. Your work exemplifies the creative freedom that drives breakthrough discoveries.


Photo credit : Stromal cells (in green), which possess memory properties, around the bronchiole (smooth musculature, in red), and specifically recruited immune cells (in pink).
© Institut Pasteur

💡 Connaissiez-vous le site e-allergie.fr ? La référence en enseignement de l’allergologie depuis près de 30 ans

Issu du CDRom Encyclopédique d’Allergologie, créé en 1998 et récompensé pour son excellence pédagogique, e-allergie.fr est aujourd’hui une plateforme de référence pour l’enseignement et la formation continue en allergologie.

🔬 Validée par des experts reconnus, constamment mise à jour, elle couvre l’intégralité des programmes universitaires (DES, FST, ex-DESC) à travers :
- 7 grands ouvrages thématiques (immunologie, pharmacologie, dermatologie, ORL, asthme, explorations biologiques…)
- 45 fiches conseil éditables à destination des patients
- Un glossaire complet
- Des renvois directs vers les RCP à jour (Base Claude Bernard – Dexther)

👩‍⚕️👨‍⚕️ Étudiants, enseignants et professionnels de santé y trouvent un outil fiable, structuré et évolutif, pensé comme un véritable support pédagogique et clinique.

🤝 Ces évolutions se font avec le soutien de la Société Française d’Allergologie et du Collège des Enseignants d’Allergologie, partenaires historiques de la plateforme.

➡️ L’accès à e-allergie.fr est désormais proposé sous forme d’abonnement annuel, garant de la qualité, de l’indépendance et de l’actualisation continue des contenus.

En savoir plus et s’abonner : https://e-allergie.fr/

#eallergie #allergologie #enseignementallergologie

De-Labelling Penicillin Allergies in the Paediatric Emergency Department

"While many children carry a penicillin allergy label, the vast majority do not have a true immunologically mediated allergy, leading to a lifetime risk of avoidable use of broad-spectrum antibiotics, higher healthcare costs, and poorer clinical outcomes."

Most children thought to have a penicillin allergy actually don't.
Giving them an alternative to a penicillin-based antibiotic (because of said "allergy") denies them from receiving the best treatment for their infection.
Any opportunity to remove the incorrect "penicillin allergy" label will help them receive better care.

via Ceri Phillips cc Damian Roland


https://lnkd.in/e5bZiEwr

On IDSA’s & HIVMA’s Science Speaks blog: Kap Sum Foong, MD, FIDSA, explores how proposed legislation can help close gaps by aligning reimbursement, EHR integration and workforce training to make penicillin allergy delabeling routine across all care settings. https://lnkd.in/eM4tmYTF

A very low maintenance dose of #peanut #oral #immunotherapy significantly increased tolerated peanut exposure and improved immunologic markers compared with strict avoidance, achieving desensitisation similar to a high dose. https://lnkd.in/dfAtjB2Y

💡 𝐖𝐡𝐚𝐭 𝐢𝐟 𝐰𝐞 𝐜𝐨𝐮𝐥𝐝 𝐭𝐞𝐚𝐜𝐡 𝐁 𝐜𝐞𝐥𝐥𝐬 𝐭𝐨 "𝐟𝐨𝐫𝐠𝐞𝐭" 𝐈𝐠𝐄??
📖 In a recent Science Immunology study, long-term allergic memory was mapped 𝐧𝐨𝐭 𝐭𝐨 𝐈𝐠𝐄 cells, but mainly to 𝐈𝐠𝐆𝟏⁺ 𝐦𝐞𝐦𝐨𝐫𝐲 𝐁 𝐜𝐞𝐥𝐥𝐬 with a type-2 imprint, primed to change from IgG1 to IgE when the allergen returns (recall).

🧬 𝐃𝐢𝐬𝐜𝐨𝐯𝐞𝐫𝐢𝐧𝐠 𝐓-𝐩𝐨𝐰𝐞𝐫
🔁 𝐓-𝐜𝐞𝐥𝐥 𝐜𝐲𝐭𝐨𝐤𝐢𝐧𝐞𝐬 as gatekeepers: 𝐈𝐋-𝟒/𝐈𝐋-𝟏𝟑 drive this switch at recall; dampen those cues and IgE recall drops. Notably, exposing these memory B cells to allergen without IL-4 can make them “𝐟𝐨𝐫𝐠𝐞𝐭” 𝐭𝐡𝐞 𝐈𝐠𝐄 𝐩𝐫𝐨𝐠𝐫𝐚𝐦 and default to 𝐈𝐠𝐆, even when IL-4 reappears later.

🧪 𝐋𝐞𝐭’𝐬 𝐥𝐞𝐚𝐫𝐧 (𝐧𝐞𝐮𝐫𝐨)𝐈𝐦𝐦𝐮𝐧𝐨𝐥𝐨𝐠𝐲 — 𝐀𝐥𝐥𝐞𝐫𝐠𝐲 𝐛𝐚𝐬𝐢𝐜𝐬
• 𝐀𝐥𝐥𝐞𝐫𝐠𝐲 = an excessive immune response to a 𝐡𝐚𝐫𝐦𝐥𝐞𝐬𝐬 𝐚𝐧𝐭𝐢𝐠𝐞𝐧 (𝐚𝐥𝐥𝐞𝐫𝐠𝐞𝐧) recognized by 𝐈𝐠𝐄 𝐚𝐧𝐭𝐢𝐛𝐨𝐝𝐢𝐞𝐬.
• 𝐈𝐠𝐄 binds to its high-affinity receptor (𝐅𝐜ε𝐑𝐈) on 𝐦𝐚𝐬𝐭 𝐜𝐞𝐥𝐥𝐬 and 𝐛𝐚𝐬𝐨𝐩𝐡𝐢𝐥𝐬; upon re-exposure, the allergen cross-links IgE → 𝐝𝐞𝐠𝐫𝐚𝐧𝐮𝐥𝐚𝐭𝐢𝐨𝐧 (histamine release…) → hives, wheezing, anaphylaxis.
• 𝐈𝐠𝐆𝟏⁺ 𝐦𝐞𝐦𝐨𝐫𝐲 𝐁 𝐜𝐞𝐥𝐥𝐬 store the “recipe”; with 𝐈𝐋-𝟒/𝐈𝐋-𝟏𝟑 they can 𝐜𝐥𝐚𝐬𝐬-𝐬𝐰𝐢𝐭𝐜𝐡 𝐛𝐚𝐜𝐤 𝐭𝐨 𝐈𝐠𝐄, helping explain relapses.

🧬 𝐂𝐡𝐚𝐥𝐥𝐞𝐧𝐠𝐢𝐧𝐠 𝐭𝐡𝐞 𝐩𝐚𝐫𝐚𝐝𝐢𝐠𝐦: the immune system is not a defense system… it is much more than that.

🔗 𝐑𝐞𝐚𝐝 𝐭𝐡𝐞 𝐩𝐚𝐩𝐞𝐫 𝐢𝐧 𝐒𝐜𝐢𝐞𝐧𝐜𝐞 𝐈𝐦𝐦𝐮𝐧𝐨𝐥𝐨𝐠𝐲: https://lnkd.in/d5zeXDDX

🔖 Save for later. 🔁 Share with your science-curious friends.

#immunology #allergy #IgE #Bcells #IL4 #IL13 #mastcells #ScienceImmunology #ChallengingTheParadigm

Key lung immune cells can intensify allergic reactions

“Alveolar macrophages have long been seen as peacekeepers in the lung,” said the first author of the study. “Our results show that during allergic responses, they can do the opposite and actually help drive inflammation.”

Using an advanced mouse model that allowed the researchers to precisely track and manipulate these lung cells, the team discovered that allergen exposure causes alveolar macrophages to send out signals that attract other immune cells into the lung. This influx amplifies inflammation and worsens allergic reactions. Remarkably, the macrophages were also found to fuse together into large ‘giant cells’ that change the structure of the lung tissue during allergy.

Mechanistically, upon allergen exposure, interleukin-33-activated innate type 2 lymphoid cells (ILC2s) produced interleukin-13, which reprogrammed trAMs through induction of the transcription factor interferon regulatory factor 4 (IRF4).

IRF4 suppressed the expression of the transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) and dismantled the PPARγ-dependent homeostatic regulon that defines trAM identity, while initiating a transcriptional program driving chemokine production and cell fusion. This resulted in the recruitment of granulocytes, ILC2s, and regulatory T cells, as well as the formation of multinucleated giant cells in the alveolar niche.

These findings challenge the long-standing view that alveolar macrophages are stable cells that resist change. Instead, the study reveals that they are surprisingly flexible and can be reprogrammed by their environment, sometimes with harmful consequences.
#ScienceMission #sciencenewshighlights
https://lnkd.in/gMDVj3Rq

📢 Happy to share our latest paper on RESA, a risk prediction tool for asthma attacks (exacerbations) in severe asthma, developed using data from 27 regions across the planet.

Led by Dr. Wenjia Chen, RESA is a modular model with a core and optional set of predictors, predicting the risk of any or frequent attacks. This is a highly relevant outcome, as we strive for more efficient management of this important subgroup of asthma.

★ The more we tried, the clearer it became that a universally applicable model without local adjustment may not be realistic. The team concluded that the most responsible approach is to treat background exacerbation risk as an input parameter.

This reflects the nature of asthma attacks, a biological event, but also shaped by subjective symptom perception, standards of care, and environmental factors.

This real-world heterogeneity remains hidden until we try to quantify the risk, and is difficult to identify in the harmonized world of trials.

This work would not have been possible without the sustained efforts behind large-scale initiatives like ISAR and NOVELTY.

👉 Open access paper in American Academy of Allergy, Asthma & Immunology - AAAAI journal: https://lnkd.in/gMd7FepJ

👉 Web app (RESAScore.com): https://www.resascore.com/

International collaboration: The University of British Columbia | Collaboration for Outcomes Research and Evaluation (CORE) | National University of Singapore | Observational & Pragmatic Research Institute | AstraZeneca | Respiratory Evaluation Sciences Program

How do clinicians manage pediatric egg & milk allergy across countries?
🇮🇪 Ireland: Ladders dominate (egg & milk), OIT not offered.
🇨🇦 Canada: Mixed model — avoidance + ladders + OIT in some centers.
🇪🇸 Spain: Avoidance most common — yet OIT widely available.

Snapshot: A multinational survey reveals striking variation in #diagnostics, #treatment choices, and follow‑up intensity across Ireland, Canada, and Spain.

🔗 https://lnkd.in/dX_R8f4u
.
#FoodAllergy #eggallergy #milkallergy #PAI_Journal #irland #canada #spain #oit #multinationalsurvey #foodallergymanagement #foodladder #internationalsurvey #oralimmunotherapy #letter #openaccess

📣 Allergies : une spécialité médicale, pas un terrain pour les pratiques non scientifiques

Sur les réseaux sociaux, on voit fleurir de nombreuses « techniques » présentées comme des solutions miracles pour comprendre ou soigner les allergies.

Elles se parent souvent d’un discours séduisant, rassurant, pseudo‑scientifique… et elles ciblent particulièrement les personnes perdues face à leurs symptômes.

Le problème, c’est que ces approches ne reposent sur aucune base médicale.
Leur discours, souvent construit sur des concepts flous ou invérifiables, peut représenter un véritable danger pour les personnes allergiques.

Les allergies ne sont ni une intuition, ni une énergie, ni une impression.
Ce sont des maladies du système immunitaire, qu’elles soient immédiates (médiation IgE) ou retardées (médiation cellulaire).

Elles déclenchent une cascade de réactions immunitaires complexes, qui n’ont absolument rien à voir avec des manipulations symboliques, des gestes approximatifs ou des méthodes sans fondement scientifique.

🩺 L’allergologie est une spécialité médicale reconnue comme telle depuis 2017, fondée sur :
• des tests validés
• des protocoles rigoureux
• une compréhension croissante des mécanismes immunitaires mis en jeu
• des traitements efficaces et sécurisés

S’éloigner de cette expertise, c’est prendre le risque :
– d’un mauvais diagnostic
– d’un retard de prise en charge
– d’une exposition à des risques non maîtrisés
– d’une aggravation des symptômes

🎯 Pour les allergies, la sécurité passe par la science.
Consulter un professionnel formé, c’est se protéger.
Faire confiance à des méthodes non validées, c’est le danger dont certains n’ont pas conscience. Surfer sur la détresse des personnes allergiques a coup de séances coûtant parfois une blinde est- ce bien raisonnable ?

Bien sûr, d’autres spécialités connaissent aussi ces mêmes problèmes !!

Open Access: Development of Betalactam-Predictor: A Clinical Decision Tool for Delabeling Low-Risk Betalactam Allergy Patients. Initial Validation in Penicillin Allergy. First author: Marina Labella; corresponding authors: Elizabeth Phillips, María José Torres


Read the article here: doi.org/10.1111/all.70222


Beta-lactam predictor has emerged as a new tool for delabeling #penicillin allergy. External validation has shown a specificity of 93% for detecting low-risk patients. This score could potentially reduce diagnostic costs and the negative consequences associated with incorrect antibiotic allergy labels.

#Allergy_journal
Read more articles published in #Allergy on penicillin allergy here: https://lnkd.in/gfs_z4g6

🔔 Read our latest paper published "Scope, Features, and Utility of Australian Penicillin Allergy Delabelling Protocols: A Descriptive Analysis" by Prof. Dr. Sandra M Salter et al.

🔗 Link: https://brnw.ch/21wZQJI


🎓 These findings emphasise the complexity of clinical decision-making around penicillin allergy and suggest a need for standardisation of PADL-Ps to maximise delabelling benefits and safety across Australian healthcare settings.

#PenicillinAllergy #PenicillinAllergyDelabelling #PADL #AntimicrobialStewardship #PatientSafety #HealthcareQuality #ClinicalGuidelines #ASCIA #AllergyManagement #MedicationSafety #HealthcareResearch #ClinicalDecisionMaking #StandardisationInHealthcare #AustralianHealthcare #PaediatricCare #AdultMedicine #EvidenceBasedPractice #HealthPolicy #InfectiousDiseases #QualityImprovement

ALLERGIC REACTION
Immunology & Medical Laboratory Science

1. Introduction

An allergic reaction is a common immunological phenomenon encountered in clinical practice. It represents an inappropriate and exaggerated immune response to substances that are ordinarily harmless. While many allergic reactions are mild, some can be severe and life-threatening, emphasizing the importance of understanding their mechanism, diagnosis, and laboratory relevance.

2. Definition

An allergic reaction is an immunologically mediated hypersensitivity response that occurs when a previously sensitized individual is re-exposed to a specific allergen, leading to activation of immune cells and release of inflammatory mediators.

Most allergic reactions are classified as Type I (IgE-mediated) hypersensitivity reactions.

3. Allergens and Routes of Exposure

3.1 Common Allergens

Allergens are substances capable of inducing allergic reactions in susceptible individuals.
•Inhaled allergens: pollen, dust mites, mold spores, animal dander
•Ingested allergens: peanuts, shellfish, eggs, milk, drugs
•Injected allergens: insect stings, injectable drugs, blood products
•Contact allergens: latex, cosmetics, metals (nickel), detergents

3.2 Routes of Entry
•Respiratory tract
•Gastrointestinal tract
•Skin
•Bloodstream

The route of entry influences the clinical presentation.

4. Immunological Mechanism of Allergic Reaction

Allergic reactions occur in two main phases:

4.1 Sensitization Phase (Primary Exposure)

This phase occurs during the first exposure to the allergen and does not produce clinical symptoms.

Steps involved:
1. The allergen enters the body.
2. Antigen-presenting cells (APCs) process the allergen.
3. APCs present the antigen to CD4⁺ T helper (Th2) cells.
4. Th2 cells release cytokines such as IL-4 and IL-13.
5. These cytokines stimulate B cells to produce IgE antibodies.
6. IgE binds to high-affinity FcεRI receptors on mast cells and basophils.

The individual is now sensitized.


4.2 Effector Phase (Re-exposure)

Upon subsequent exposure to the same allergen:
1. The allergen binds to IgE on mast cells.
2. Cross-linking of IgE occurs.
3. Mast cells undergo degranulation.
4. Inflammatory mediators are released, producing clinical symptoms.

5. Chemical Mediators Released

5.1 Pre-formed Mediators
•Histamine: causes vasodilation, itching, edema, and bronchoconstriction

5.2 Newly Synthesized Mediators
•Leukotrienes: bronchoconstriction and mucus secretion
•Prostaglandins: inflammation and pain
•Cytokines: recruit eosinophils and other inflammatory cells

These mediators are responsible for the acute and late-phase reactions.

#MedicalLaboratoryScience
#Immunology
#AllergicReactions
#PatientSafety
#LaboratoryMedicine
#HealthcareEducation
#MLS

What Your IgG Test Results Mean (and Don’t Mean)
 
TL;DR: IgG sensitivity tests can’t tell you what foods you're sensitive to.
 
IgG sensitivity tests claim to work by measuring levels of IgG antibodies in your blood against specific foods. Some test up to 100 foods, and the idea is that if your body makes a lot of IgG to a certain food, it means your immune system sees that food as a “problem.” Companies that make these tests say this immune response may be linked to symptoms like bloating, fatigue, headaches, or skin issues. Based on the results, they recommend avoiding foods that show high IgG levels.
 
However, these tests measuring IgG antibodies, aren't scientifically proven. Experts, including the American Academy of Allergy, Asthma, and Immunology (AAAAI), say IgG antibodies actually show normal exposure and tolerance to a food. Meaning that your body tolerates those foods, not that you're sensitive to them!
 
These tests are expensive and can lead to unnecessary food restrictions and can cause anxiety, nutrient deficiencies, and a bad relationship with food.
 
✅ An elimination diet, done with a healthcare professional, is still the best way to pinpoint food sensitivities. It takes time, but it’s the most trusted method!
 
https://lnkd.in/dBhYfZf2

https://lnkd.in/dYJ47Wjh
 
#Debunked #FoodSensitivity #GutHealth #EliminationDiet

#eaccmeaccredited
Dr. Andreas Horn / Fortbildungen und Beratungen
#eaccme
#cme
#liveevents
#allergology

Allergies alimentaires : de grandes disparités à l’échelle mondiale
L’article proposé par la WAO Sur un projet international mené auprès de 150 centres dans 50 pays met en évidence de grandes différences dans la prise en charge des allergies alimentaires selon les pays,que ce soit dans les possibilités diagnostiques ou le prix des traitements d’urgence .
-Le test cutané est utilisé mais certaines régions d’Afrique et d’Asie y ont un accès inégal . 
- les IgE spécifiques, souvent utilisées en alternative. 
-L’immunothérapie orale est surtout pratiquée en Europe occidentale, puis en Amérique du Nord, en Europe du Sud et en Europe du Nord. L’omalizumab est également utilisé notamment en Europe occidentale, en Amérique du Nord, en Asie de l’Est et en Océanie.
-La sévérité des réactions varie fortement selon les zones géographiques.
L’utilisation d’adrénaline va de 3 % en Asie du Sud à 50 % en Afrique australe, avec des taux importants en Asie de l’Est, en Asie occidentale, en Europe du Sud et en Amérique du Nord. La disponibilité de l’adrénaline elle-même est très variable selon les pays, et certains n’y ont pas accès aux auto‑injecteurs,
Allergènes :Avant 5 ans, le lait et l’œuf sont les allergènes les plus fréquents. Entre 5 et 11 ans, l’œuf >du lait, >l’arachide et des fruits à coque. Chez les adolescents, l’arachide le plus courant au niveau mondial, suivie des noix et des crustacés. Chez les adultes, les crustacés, les noix, l’arachide et le poisson sont les allergènes les plus souvent rapportés,

Ces résultats montrent que les allergies alimentaires représentent un enjeu mondial majeur, influencé par l’accès aux diagnostics, aux traitements, aux auto‑injecteurs d’adrénaline et aux soins d’urgence. Selon l’outil DEFASE, environ 3 % des patients pourraient être classés comme souffrant d’allergies alimentaires sévères, un taux comparable à celui observé dans l’asthme sévère réfractaire.
https://lnkd.in/ebF3d252
Cet article est très intéressant et engage à comparer les prix dans différents pays :
les tarifs hors assurance sont d’environ 1 000 à 3 000 dollars pour une admission aux urgences aux États‑Unis et 3 000 à 10 000 dollars pour une journée en soins intensifs, alors qu’en Thaïlande une journée de soins intensifs coûte hors assurance 900 à 2 700 euros, tandis qu’en France les coûts hospitaliers sont beaucoup plus faibles grâce à la prise en charge publique, mais peuvent devenir élevés pour les personnes sans aucune assurance

Aux USA les prix vont de 199 dollars pour le nouveau spray nasal d’adrenaline à près de 300 dollars pour le système parlant injectable. Et 600 euros pour le plus connu ( tarifs hors assurance ) En France il faut compter entre environ 62 et 91 euros pour deux dispositifs . , l’Assurance maladie rembourse 65 % du prix des auto‑injecteurs d’adrénaline et, dans la plupart des cas, les complémentaires santé prennent en charge le reste du coût.

New Guidance Sets Standard for Paediatric Antibiotic Allergy Testing: in a new report, investigators USDAR-Peds introduce unified, evidence-informed protocols designed to guide clinicians in evaluating suspected antibiotic hypersensitivity in children. https://lnkd.in/dpV7Cb-S