Background: Food challenges carry a burden of safety, effort and resources. Clinical reactivity and presentation, such as thresholds and symptoms, are considered challenging to predict ex vivo.
Aims:To identify changes of peripheral immune signatures during oral food challenges (OFC) that correlate with the clinical outcome in patients with peanut allergy (PA).
Methods: Children with a positive (OFC + , n = 16) or a negative (OFC − , n = 10) OFCoutcome were included (controls, n = 7). Single-cell mass cytometry/unsupervised analysis allowed unbiased immunophenotyping during OFC. Results: Peripheral immune profiles correlated with OFC outcome. OFC + -profiles revealed mainly decreased Th2 cells, memory Treg and activated NK cells, which had an increased homing marker expression signifying immune cell migration into effector tissues along with symptom onset. OFC − -profiles had also signs of ongoing inflammation, but with a signature of a controlled response, lacking homing marker expression and featuring a concomitant increase of Th2-shifted CD4 + T cells and Treg cells. Low versus high threshold reactivity-groups had differential frequencies of intermediate | 1021 KLUEBER Et aL.