Allergy from Peanuts – Treatment Options

Introduction:

Peanut allergy (PA) is an adverse immune response to a peanut allergen. Ara h1 and Ara h3 (cupin proteins), Ara h2 and Ara h6 (prolamin proteins) are major allergenic proteins found in peanuts. Allergic reaction between these allergens and immunoglobulin E (IgE) antibodies develops symptoms. Mild to moderate symptoms include hives, itching, abdominal pain, and sneezing, while severe anaphylaxis can cause throat swelling, difficulty breathing, and a drop in blood pressure. PA is a specific form of Type I hypersensitivity characterized by an IgE-mediated immune response leading to allergic symptoms, Therapy for peanut allergy is constantly evolving, and new perspectives are ongoing to develop.

PA proteins: 

2S albumins (Ara h2, and Ara h2), 7S globulins (Ara h 1) and 11S globulins (Ara h 3 and Ara h 4). These proteins act as allergens primarily due to their structural features, stability, and the specific epitopes they present.

What are Epitopes and their role in allergic reactions?

Epitopes are specific sites on the allergenic proteins where IgE antibodies bind, initiating the allergic response. The stability and structure of these epitopes, along with their recognition by the immune system, underpins the allergenicity.

What are peanut protein allergens?   

• Seed storage proteins: Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7 are the primary allergen.
• Non-storage proteins: Ara h 8 and Ara h 9.
• Pathogen Related protein: Ara h 5.
• Peanut Enzymes:  Ara h 10 and Ara h 11.

These proteins are stable to heat, cooking, resist digestion in the gastrointestinal tract and elicit an immune response (allergenicity).

Are allergies curable?

Currently, allergies are generally not considered curable, but they are manageable with various treatments.

Treatment options for peanut allergy focus on managing symptoms and preventing severe allergic reactions.

• Strict Avoidance: is to avoid peanuts and peanut-containing products.
• Epinephrine Auto-Injectors (EpiPen, Auvi-Q) for the treatment for anaphylaxis.
• Antihistamines help relieve itching and hives. Bronchodilators (albuterol inhalers) to relieve breathing difficulties from asthma or respiratory symptoms.
• Oral Immunotherapy (OIT): FDA-approved Palforzia must be given under medical supervision to mitigate allergic reactions upon peanut exposure, and to build tolerance.
• Sublingual Immunotherapy (SLIT): Small dose of peanut protein in a liquid or tablet is held under the tongue, for a few minutes and then swallowed (desensitization).
• Epicutaneous Immunotherapy (EPIT): Application of a patch containing peanut protein to the skin to reduce the sensitivity to peanuts(desensitize) the immune system. (example: Viaskin®peanut (50 µg, 100 µg, 250 µg) patch).
• Biologic Therapies (Anti-IgE): Involves binding of IgE or other immune mediators with Monoclonal Antibodies (Omalizumab -Xolair) to reduce the severity of allergic reactions.
• Dietary Management: Patients should understand alternative names for peanuts on the label and communicate their allergy to restaurant staff.
• Probiotics such as Lactobacillus rhamnosus may help in conjunction with immunotherapy.
• T-cell Modulation Therapies targets t-cells to promote a shift from an allergic (Th2) to a non-allergic (Th1/Th17) immune response.
• Others: DNA Vaccines, peptide immunotherapy.

Can genetic engineering reduce allergenicity?

May reduce the allergenicity of peanut proteins through techniques such as RNA interference and CRISPR-Cas9 gene editing.

Novel Processing Strategies:

Hydrolysis with proteases Alcalase and Flavourzyme decreases the IgE-binding capacity of roasted peanut protein extracts and decreased levels of Ara h 1, Ara h 2, and Ara h 3.

Precipitation:

When enzymes (peroxidase and polyphenol oxidase- PPO), or phenolic compounds (caffeic acid) were used to cross-link peanut proteins, reduced the IgE-binding capacity of peanut extract.

Is refined peanut oil (RPO) allergenic?

No. RPO is not a threat to peanut-allergic individuals because refining process enough protein is removed from the oil to render it essentially allergen free. (reduced to ∼2 μg/ml which is well below the level required to elicit a reaction i.e.,100 μg unless the person consumes more than 50ml of oil). Furthermore, Food Allergen Labeling and Consumer Protection Act (FALCPA) states that highly refined oils from the Big 8 are not major food allergens.

Allergen-Free Peanut Products:

1) Apeel’s Allergen-Free Peanuts and

2) Arlo’s hypoallergenic peanut protein powder (patented)

Is cold-pressed peanut oil allergenic?

Yes. Cold-pressed peanut oil is not free from peanut allergens and can trigger allergic reactions in individuals with peanut allergies.

Are peanut skins (seed coats) allergenic?

Peanut skins consist of approx. 18% protein have potential to elicit an allergic reaction in peanut-allergic individuals, but the presence of health promoting polyphenolic compounds may attenuate the adverse response.

Diagnosis and prevention of PA:

Diagnosis involves understanding patient history, skin prick tests, specific IgE blood tests, oral food challenges, and component-resolved diagnostics (CRD) to detect IgE sensitivity to individual allergen molecules. Preventive methods include early peanut introduction for high-risk infants, strict avoidance of peanuts, emergency preparedness with epinephrine auto-injectors, education, and potentially desensitization therapies. These strategies reduce the risk of allergic reactions and improve the quality of life for individuals with peanut allergies.

Conclusion:

The primary treatment for PA is to strict avoidance of peanuts and peanut-containing products. Patients and caregivers must be aware of sources of peanuts displayed on label ingredient list. Emergency medications like epinephrine auto-injectors are crucial for managing severe reactions. Epicutaneous immunotherapy desensitize patients to peanuts. Oral peanut immunotherapy (OIT) can help some children avoid serious reactions if exposed to peanut protein. Advances in understanding the immune system may eventually lead to breakthroughs that could cure some types of allergies. By targeting specific allergenic proteins, it is possible to create peanut varieties that are safer for individuals with peanut allergies. Understanding the structure and function of 2S, 7S, and 11S proteins, and epitopes of peanut allergens along with availability of regulatory approved medications help in developing strategies for allergy diagnosis, prevention and treatment options.

DISCLOSURE STATEMENT:

Disclaimer: The information provided in this blog is for general informational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider or allergist for any health-related concerns.