Elucidating molecular mechanisms of allergic sensitization to olive pollen through transcriptomics

Background Olive pollen allergy, a leading cause of seasonal allergic rhinitis and asthma in Mediterranean regions, is becoming increasingly relevant worldwide due to the expansion of olive cultivation. Despite its significant public health impact, the molecular mechanisms underlying sensitization to olive pollen remain poorly understood. Methods In this study, RNA sequencing was used to perform transcriptomic profiling on in vitro- stimulated Peripheral Blood Leukocytes (PBLs) from both allergic patients and healthy controls, to identify gene expression changes triggered by olive pollen in allergic individuals. Validation by RT-qPCR was subsequently performed in an independent cohort to confirm the expression patterns of selected DEGs. Results A total of 37 differentially expressed genes (DEGs) were found exclusively in the patient group. Validation by RT-qPCR in an independent cohort confirmed the expression patterns of selected DEGs. Functional enrichment analyses associated these DEGs with immune pathways, ossification processes, and cytokine activity. Notably, upregulated genes such as AREG , IL31RA , and IL18R1 were associated with TH 2 responses and asthma pathogenesis, while downregulated genes including GREM1 and CCL1 were related to chemotaxis and immune regulation. Protein-protein interaction (PPI) network and hub gene analyses highlighted potential molecular drivers of allergic inflammation. Chromosomal mapping revealed clustering of DEGs on chromosomes previously associated with asthma susceptibility. Furthermore, exploratory correlation analyses identified correlation between TGM2 expression and total IgE, and between SHROOM2 expression and Ole e 7-specific IgE, highlighting these genes as candidates for future evaluation. Conclusion Overall, this study provides new insights into the transcriptomic landscape of olive pollen allergy, identifying candidate biomarkers and biological pathways with translational relevance for improving diagnosis and advancing personalized treatment strategies in allergic diseases.