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.