Association Between Peach and Olive Pollen Non-Specific Lipid Transfer Protein Allergy and HLA Class II Phenotype

Concomitant sensitisation to non-specific lipid transfer proteins (nsLTPs) from olive pollen (Ole e 7) and peach (Pru p 3) has been observed in the south of Spain. In the search for reasons to explain this observation, we studied a potential causal relationship between Human Leukocyte Antigen (HLA) molecules and nsLTP sensitisation. For this purpose, eighteen Ole e 7-monosensitised (MONOLE) patients, 22 Pru p 3-monosensitised (MONPRU) patients, and 22 bisensitised (BI) patients were genotyped for HLA class II alleles. Complementarily, T-cell epitopes were predicted with the Immune Epitope Database analysis tool to test HLA epitope presentation. Our results showed a significant increase in DRB1*11 and DQB1*03 frequencies in MONPRU patients and DRB1*04 frequency in MONOLE patients. Additionally, T-cell epitope analysis revealed high binding affinity between the predicted Pru p 3 epitopes and DRB1*11 and between the predicted Ole e 7 epitopes and DRB1*04, suggesting that presentation of these epitopes may be favoured and predisposing individuals to sensitisation. Conversely, low DQB1*05 frequency and poor binding ability of predicted epitopes from both nsLTPs postulated this allele as a possible protective factor to sensitisation. Variations in the binding affinity between nsLTP epitopes and HLA molecules may underlie individual susceptibility to nsLTP allergy.