Ara h 2 is a specific protein found in peanuts, recognized as a primary cause of allergic reactions in many individuals with peanut allergy. This protein’s presence is a significant factor in understanding and managing peanut allergies. Its study has advanced diagnostic approaches and opened avenues for potential treatments.
Understanding Ara h 2
Ara h 2 is a major peanut allergen, classified as a 2S albumin seed storage protein. It is known for its high stability. Its structure, stabilized by disulfide bridges, contributes to its resistance. It can withstand high temperatures, such as those encountered during roasting.
Ara h 2 also resists breakdown by digestive enzymes in the gastrointestinal tract. This resilience means the protein remains largely intact after consumption, increasing its likelihood of triggering an immune response. This resistance to heat and digestion contributes to its potency as an allergen.
Ara h 2’s Central Role in Peanut Allergy
Ara h 2 is a significant allergen due to its widespread recognition by peanut-allergic individuals. Studies indicate that 80-90% of those with peanut allergy react to Ara h 2, making it one of the most frequently recognized peanut allergens. Sensitization to Ara h 2 is linked to more severe allergic reactions, including life-threatening anaphylaxis.
The immune response to Ara h 2 involves the production of specific IgE antibodies. When a sensitized individual consumes peanuts, these IgE antibodies bind to Ara h 2, triggering the release of histamine and other chemicals from mast cells, leading to allergic symptoms. Ara h 2 and Ara h 6 are often co-sensitized, meaning individuals allergic to peanuts frequently react to both proteins. These two proteins are considered potent, and their co-sensitization is associated with increased reaction severity.
Clinical Significance and Future Directions
The presence of Ara h 2 is used in diagnostic tests, such as component-resolved diagnostics, to identify peanut allergy. Specific IgE testing for Ara h 2 is considered a reliable antibody test for confirming peanut allergy, often providing better predictive value than tests using whole peanut extract. For instance, an Ara h 2 level of 0.1 kU/L or less can indicate peanut tolerance, while levels of 5.0 kU/L or greater are predictive of a true peanut allergy.
Identifying sensitization to Ara h 2 helps clinicians assess the risk of severe reactions and guide patient management, potentially reducing the need for oral food challenges. Research is also exploring allergen-specific immunotherapies that target Ara h 2. Scientists are working on developing “hypoallergenic” variants of Ara h 2, which aim to reduce IgE binding and allergic reactions while still stimulating a beneficial immune response. These modified proteins could be used in future vaccines to desensitize individuals to peanut allergens, offering a path toward long-term tolerance for those affected by peanut allergy.