D1.09 - Mast cell disorders in children with food-induced anaphylaxis

Food allergies amongst children are increasingly prevalent and can lead to life-threatening anaphylaxis. Recent data suggests hereditary α-tryptasemia (HαT) is associated with venom, drug, and idiopathic anaphylaxis, but its role in food allergy is still not fully understood. Our objective was assessing the association of HαT with food-induced anaphylaxis and immunological markers in children.

From 2022 to 2024 we prospectively recruited children with systemic allergic reactions referred to a single tertiary paediatric centre.  All underwent tryptase genotyping by ddPCR and examination for KIT p.D816V in PBL using a highly sensitive PCR test. We in detail evaluated clinical characteristics, severity of reaction and causes of reaction. We also included 59 healthy controls, who underwent minor surgical procedures.

Of 413 recruited children, 129 individuals were diagnosed with food‑induced anaphylaxis (36 with SGSAR 2 and 93 with SGSAR 3–5 grades). The prevalence of HαT in food‑induced anaphylaxis was 8.5% (n = 11 of 129) and was the highest in children with peanut-induced anaphylaxis (n = 5 of 31; 16.1%). On the other hand, the prevalence in healthy controls was 3.4% (n = 2 of 59). Interestingly, the level of sensitisation was higher in HαT versus non‑HαT (sIgE of 98.1 vs 18.55 kUₐ/L), with a marked difference in peanut allergy (561 vs 8.94 kUₐ/L). The anaphylaxis severity was not associated with a-tryptase. In addition, only one KIT p.D816V positive individual was identified (with hazelnut allergy), while no subject had both KIT p.D816V and HαT.

HαT was associated with peanut‑induced anaphylaxis and was overall higher in children with food-induced anaphylaxis, compared to the prevalence reported for the general population or healthy controls. KIT p.D816V was rare and did not co‑occur with HαT.