D1.82 - Pancake Syndrome: Molecular and Diagnostic Heterogeneity of Mite Sensitization

Pancake Syndrome (PS) is an anaphylactic reaction triggered by the ingestion of mite-contaminated flour. Despite the central role of mite sensitization in its pathophysiology, the diagnostic coherence across skin testing, extract-based IgE and molecular IgE profiling remains unclear. 

Eleven patients with suspected PS were clinically characterized and underwent skin prick testing (SPT), extract-based specific IgE measurement (≥0.35 kUA/L), and molecular allergy profiling using ISAC microarray (≥0.3 ISU). Diagnostic concordance was analyzed descriptively, and extract–component correlations were assessed using Spearman’s rank test. Associations between molecular sensitization burden and clinical severity features were explored.

The cohort (n=11), with 63.6% female, had a mean age of 34.4±18.3 years. All patients had respiratory atopy (100% rhinitis, 45.5% asthma) and 72.7% had documented NSAID allergy. Mean serum basal tryptase was 4.67±1.52 ng/mL, and median total IgE was 130 kUA/L (IQR 103–317). 

High sensitization rates were observed across all three diagnostic modalities. SPT positivity was 81.8% for D. pteronyssinus (Dp) 90.9% for D. farinae (Df), and 100% for L. destructor (Ld). Extract-based IgE positivity ranged from 72.7% to 90.9% depending on species. At the molecular level, Der p2 (81.8%), Der p23 (72.7%) and Blo t5 (90.9%) were the most frequently detected components.  

Dp showed strong diagnostic concordance, with significant correlations between extract IgE and Der p2 (ρ=0.75, p=0.013) and Der p23 (ρ=0.78, p=0.008). In contrast, Df demonstrated heterogeneity, with lower molecular representation (Der f1: 36.4%; Der f2: 63.6%) and no significant extract–component correlations. For Ld, SPT was positive in all patients and extract-based IgE in 90.9%, whereas the molecular component Lep d2 was detected in only 54.5%. Nevertheless, extract IgE levels correlated significantly with Lep d2 (ρ=0.73, p=0.016). Despite the high prevalence of Blo t5 sensitization, no correlation was observed between extract-based IgE to B. tropicalis and Blo t5 levels (ρ=0.15, p=0.675). 

No associations were identified between molecular sensitization patterns and clinical severity markers. 

PS is associated with heterogeneous sensitization patterns with marked variability across mite species. While Dp shows strong diagnostic agreement, other mites exhibit whole allergen–molecular dissociation, suggesting the presence of cross-reactivity and/or other unknown molecular components.