Background:
The global prevalence of IgE-mediated peanut allergy (PA) is estimated to be between 0.2% to 4.5% depending on country (1), with the UK prevalence of PA in children being 2%. Approximately 20% of peanut allergic patients outgrow their allergy over time (2, 3) but using biomarkers to help predict which children this is more likely to occur in is less understood.
The gold standard to assess for diagnosis and possible resolution of food allergy is the oral food challenge (OFC). (4) However, this test comes with the risk of life-threatening anaphylaxis, is time-consuming, laborious, and costly, especially if multiple food challenges are needed to assess changes in allergic status. Other allergy tests, such as skin prick tests (SPT), specific-IgE (sIgE) to peanut and peanut components, are more commonly used to help establish PA diagnosis. (5) They can also be used to understand resolution and, specifically, to help determine the right time to reintroduce an allergen back into the diet. More recently, the basophil activation test (BAT) and mast activation test (MAT) have been demonstrated to have clinical utility to support the diagnosis of food allergy. (6, 7) The MAT works by using LAD2 mast cells (a human mast cell line) which are sensitised with patient plasma or serum, stimulated with allergen (e.g. peanut) and CD63 expression is measured using flow cytometry. Both BAT and MAT have been shown to have high specificity (ranging between 96 and 100%) in diagnosing PA (7) but due to practical reasons, is primarily available in the research setting.
Food allergies, such as egg and cow’s milk allergies, are commonly outgrown (8, 9) but for peanut and tree nut/sesame allergies, this occurs less frequently. Decreasing SPT wheal size and levels of allergen-sIgE over time are suggestive of food allergy resolution. (10) However, the use of MAT in the context of allergy persistence or resolution has not yet been investigated.
The aims of this study were to assess the utility of different diagnostic biomarkers to characterize different trajectories of PA and PS in a general population of children over the span of a decade. We compared results between peanut allergic and peanut sensitised but tolerant children across different time points to better understand their use in predicting PA persistence or resolution over time.