B-060 Prevalence of CCD and profilins antibodies in a seasonal allergy study

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Abstract Background Allergen sources are complex and heterogeneous mixtures of proteins, which may contain from innocuous IgE-binding structures such as CCDs (cross-reactive carbohydrate determinants), which are not associated with symptoms, to a panallergen such as profilin, which is associated with multiple sensitizations to pollen and pollen-food-latex syndromes. CCDs are present in many plant and animal allergens and cause strong cross-reactivity due to the high similarity of their structure. They complicate the interpretation of positive in vitro diagnostic results because they do not associate symptomatology and, thats why, the determination of specific IgE antibodies against CCDs can provide useful information when positive IgE results are not consistent with the clinical picture. Profilins are ubiquitous proteins present in all eukaryotic cells and identified as allergens in pollen, latex and plant foods. The highly conserved structure explains the cross-reactivity of IgE antibodies against plant profilins and their designation as panallergens. As a panallergen, profilin is associated with multiple pollen sensitization and pollen-food-latex syndromes that the allergist must be aware of for accurate diagnosis and successful treatment of allergic diseases. We intend to evaluate the prevalence of these two markers with a new diagnostic tool, since profilins and CCDs are the substances most likely to cause in vitro cross-reactivity. Methods In our study 8,242 adults who presented rhinoconjunctivitis and visited their primary care center were included. The samples were analyzed in serum samples which were routinely processed in our laboratory with the EUROLINE Mediterranean Inhalation 2 (IgE) assay from Euroimmun® from February to July 2023, according to the manufacturer’s protocols. Patients with specific IgE levels ≥ 0.35 kU/L were identified as sensitized to allergen. Results A total of 8,242 patients were enrolled in this study, 5,173 women and 3,069 men, ranging in age from 15 to 65 years. Of these, 279 patients (3.39%) had antibodies against CCD, 570 (6.92%) antibodies against profilins and 183 (2.22%) had both. A higher prevalence of these antibodies was observed in men (CCD, n = 168, 5.47%; Profilins, n = 308, 10.04%) than in women (CCD, n = 111, 2.15%; Profilins, n = 262, 5.06%). Both markers were more frequently found in the presence of specific IgE antibodies to grass and weed pollens. Conclusions The possibility of detecting the presence of IgE antibodies against CCD and panallergenic profilins is useful to detect cross-reactivity in vitro, which could explain the differences found between laboratory results and patients' symptoms, helping the allergist to make a diagnosis with greater certainty and accuracy.