Clinical and immunological markers of peanut allergy severity and tolerance in children

Background Improved diagnostic tools are needed to assess the risk of severe peanut allergy (PA) and/or predict its resolution. Methods This prospective multicenter cross-sectional study with follow-up elements (2020–2024) included children aged 3 months–18 years with confirmed PA. Diagnosis relied on clinical history, skin-prick test wheals (SPT), peanut sIgE, and/or oral food challenge (OFC). Children with isolated systemic cutaneous reactions (World Allergy Organization—WAO grade 1) were compared with children with WAO grade ≥2 reactions. Basophil activation testing (BAT) and component-resolved diagnostics were performed in all participants, and OFC assessed tolerance in selected children. Results Among 51 children (24 WAO grade 1 and 27 grade 2–5), those with anaphylaxis had larger SPT wheals ( p = 0.037) and peanut sIgE levels ( p = 0.036). Children with anaphylaxis had greater sensitization to Ara h 1 ( p = 0.021), Ara h 2 ( p = 0.041), and Ara h 6 ( p = 0.030) and higher BAT responses after adjustment for age, total IgE, and the number of food allergens to which they were allergic. Overall, receiver operating characteristic curve analyses showed area under the curve values ranging from 0.75 to 0.8 for Ara h 1, peanut sIgE, Ara h 2, Ara h 3, and Ara h 6 and SPT and BAT at greatest concentrations. OFC was performed in 20 children (6 with anaphylaxis). Tolerance was associated with lower sIgE ( p = 0.033), Ara h 2 ( p = 0.032) and Ara h 6 ( p = 0.020), and BAT showed a possible association ( p = 0.060) after adjustment for relevant confounders. Conclusion Several biomarkers, including peanut SPT, sIgE, Ara h 1, Ara h 2, Ara h 6, and BAT showed moderate discrimination between systemic cutaneous reactions and anaphylaxis, while peanut sIgE, Ara h 2, and Ara h 6 were associated with clinical tolerance. Evaluating these biomarkers may help reduce the need for OFCs in selected cases.