002007 - Quercus pollen as the primary sensitizer in patients with PR-10 sensitization in Salamanca

The study of Quercus pollen is essential in the assessment of allergic diseases in Mediterranean ecosystems. In Salamanca (midwestern Spain), sensitization to Quercus pollen reaches 54%, a prevalence notably higher than that reported in other regions. Although PR-10 sensitization is classically associated with Betulaceae pollen, their scarce presence in this area cannot justify the high prevalence of these allergies. The high density of Quercus species suggests Quercus could have a primary role in PR-10 sensitization. This study evaluates the relationship between Quercus pollen and PR-10 food allergy in a region where oak, rather than birch, dominates the landscape.

This study was conducted at the Allergy Service of the University Hospital of Salamanca. All participants provided written informed consent. Patients were selected based on the presence of allergic rhinoconjunctivitis, oral allergy syndrome (OAS) induced by culprit foods and a positive skin prick test to Quercus pollen. Component-resolved diagnosis was performed using ImmunoCAP ISAC, focusing on PR-10 proteins. IgE inhibition assays were subsequently carried out using Quercus ilex pollen extract. Statistical analysis was performed using Wilcoxon signed-rank test.

Nine patients were included. The most frequently implicated PR-10–related foods were peach (50%), followed by apple (22%) and kiwi (22%). Baseline PR-10–specific IgE levels (ISAC) and post-inhibition assay results are shown in Figures 1. Paired comparisons between baseline and post-incubation IgE levels demonstrated a marked reduction across all analyzed PR-10 proteins. This decrease was statistically significant (Wilcoxon test, p < 0.001). Mean inhibition rates were high for Pru p 1 (100%), Cor a 1.0401 (88.7%), Mal d 1 (88.9%), and Bet v 1 (87.6%), and moderate for Cor a 1.0101 (71.8%). Lower inhibition percentages observed for Ara h 8 and Gly m 4 (44%) were attributed to low baseline IgE levels.

Our findings demonstrate a marked inhibition of PR-10–specific IgE binding by Quercus pollen extract. Quercus pollen appears to act as the main driver of PR-10 sensitization, supporting its role as a primary sensitizer in the Salamanca area.