D1.316 - Identification of lipid classes to differentiate anaphylactic from non-anaphylactic allergic reactions. BANA study

Anaphylaxis is a severe life-threatening reaction that appears suddenly. Nowadays no molecular or metabolic biomarker provides a robust mean to differentiate it from a mild allergic reaction. The BANA study evaluates lipidomic signals in samples of patients that suffered an anaphylactic (A) or a non-anaphylactic allergic (NA) reaction during food immunotherapy (FAIT) treatment.

Milk or egg allergic patients were included in the study throughout 2023. Baseline (B) serum samples were collected before FAIT started. A and NA reactions occurring during the initial oral food challenge or during FAIT dosing were recorded and blood sera samples were collected. We used the Brown severity score to classify allergic reactions into A or NA reactions. Lipidomic analysis of 34 B, 11 A and 28 NA sera samples was conducted using liquid chromatography-mass spectrometry (LC-MS). Statistical analyses were conducted using RStudio. Data normality was assessed using the Shapiro-Wilk test, and either ANOVA followed by Tukey’s post hoc test or Kruskal-Wallis followed by Dunn’s multiple comparisons test was performed, as appropriate. Direct pairwise comparisons between A and NA reactions were subsequently performed for significant lipids.

Lipidomic analysis yielded a total of 409 individual lipid species found in each serum sample. Among the 13 lipid classes detected, triacylglycerol (TG), glycerophosphocholine (PC) and fatty acids (FA), were the most abundant. Statistical analysis revealed significant differences between groups in 14 lipid species, the majority corresponding to FA, and 1 glycerophosphoethanolamine (PE). Within the panel of these 14 lipids, the main significant differences were observed between A vs B. FA consistently showed higher levels in A samples compared to B ones, whereas PE detected was reduced in A. In addition, 4 FA (FA 18:2, FA 20:3_iso1, FA 20:4, FA 22:4) showed significant higher levels in A vs NA reaction, while PE16:0/18:1 exhibited an opposite trajectory. 

Our data showed a specific lipidomic profile pattern associated with anaphylaxis during FAIT. Specifically, FAs may have potential as biomarkers for distinguishing anaphylactic reactions from allergic responses.