D3.20 - Study of “in vitro” cross reactivity between nsLTP’s comparing “in silico” results with a new specific IgE test based on immunoblot methodology

Non specific lipid transfer proteins (nsLTP’s) are one of the main elicitors of food allergy in mediterranean countries, specially, Spain. Sensitizations to these allergens are associated with severe allergic reactions related with vegetables and nuts intakes. Peach component Pru p 3, plays a key role in sensitization to these allergen group and shows cross reactivity with other nsLTP’s but, nowadays, this cross reactivity has not been clearly described. A new in vitro diagnostic test based on immunoblot allows the detection of specific IgE to 10 different nsLTPs, enabling a better study and understanding of cross-reactivity among these allergens, which is key for establishing specific avoiding diets.

Objective

Description of in vitro sensitization clusters to nsLTPs with a new diagnostic test based on immunoblot and comparison of these according to cross-reactivity among this group of allergens

Prospective study conducted between September and December 2025, which included samples from patients attended at the allergy department of La Fe Hospital (Valencia, Spain) with clinical symptoms related to nsLTP allergy. Specific IgE levels were detected with EUROLINE® LTP (Euroimmun® AG, Germany) to Pru p 3, Mal d 3, Pru av 3, Ara h 9, Cor a 8, Jug r 3, Pru du 3, Pha v 3, Lac s 1, Sola LTP according to manufacturer instructions. Cross-reactivity in silico was determined through phylogenetic analysis of the proteins, which was performed with Clustal Omega® and the determination of the RDSM coefficient with PyMOL®

Phylogenetic study identified 5 different nsLTP’s branches  and matches perfectly with RDSM coefficient results (using Pru p 3 as a model).  A total of 36 patients were included in the study. Results of specific IgE levels showed 3 different clusters (based on specific IgE levels) that matches exactly with results of the in silico study (Fig.1)

In silico study identified different levels of cross-reactivity between nsLTPs, and this finding  may have clinical relevance.

EUROLINE® LTP detected three clusters of specific IgE to the different LTPs, which match with in silico results, indicating that this test could be a key diagnostic technique in the study of allergy to these allergens and in the design of personalized diets.

Clinical validation of these results is necessary.