Molecular profiling in bee venom allergy: clinical and therapeutic characterization in a Portuguese cohort.

Summary: Background. Bee venom allergy (BVA) can trigger local and systemic allergic reactions, including anaphylaxis. Recently, the molecular sensitization profile has gained importance in the reaction's stratification and venom immunotherapy (VIT). Methods. Retrospective analysis of patients with hypersensitivity to BVA, confirmed by specific sIgE to Apis mellifera ≥0.35 kU/L and/or positive skin tests to bee venom commercial extract, evaluated in specialized consultation. Demographic, clinical, and laboratory data (including molecular Api m 1, 4, and 10) were analyzed, looking for risk factors associated with the severity of the index reaction and reactions during VIT. Results. 93 patients were included (55.9% male; median age of 46 years), 57.3% with atopic comorbidities, and 23.4% with cardiovascular comorbidities. The median specific IgE to Apis mellifera was 6.7 kU/L (IQR 1.0-20.3) kU/L. Regarding the molecular profile, the median IgE to Api m 1 was 0.5 kU/L (57.5% positive out of all measurements); Api m 4 - 0.01 kU/L (11.9% positive), and Api m 10 - 0.3 kU/L (50.0% positive). No patient was monosensitized to Api m 4. The median age of the most severe sting reaction was 36 (IQR 26-48) years, with a median severity (Müeller scale) of 3 (IQR 2-3). Forty-seven patients (50.5%) underwent VIT, with 35.6% of reactions recorded. Allergic reactions during VIT were recorded in 35.6% of cases. The severity of the index reaction correlated positively with older ages (p=0.040; r=0.249), in contrast to monosensitization to Api m 1, which was an independent predictor of milder reactions (p=0.015). Sensitization to Api m 10 was associated with a higher likelihood of reactions during VIT (p=0.038) but potentially less systemic reactions at re-stings (p=0.097). Conclusions. Molecular sensitization profile appears to be relevant not only to the severity of index reactions but also during VIT. Studies of a large cohort of patients with molecular profiles are essential to validate these results and improve the clinical and therapeutic approach to BVA.

Pollen proteases compromise the airway epithelial barrier through degradation of transmembrane adhesion proteins and lung bioactive peptides.

BACKGROUND: Allergic disorders, such as seasonal rhinitis and asthma, are increasing causes of morbidity worldwide and often result from exposure to airborne pollen. Pollen allergy has a remarkable clinical impact all over Europe. In fact, epidemiological longitudinal studies confirm that pollen species usually considered with low allergenic potential became more recently responsible for intense allergic reactions. In this study, we aimed to characterize major pollen proteolytic activity and evaluate its contribution to the immunologic and inflammatory response to airborne allergens. METHODS: Proteolytic activity in four pollen diffusates with distinct allergenicity, Olea europaea, Dactylis glomerata, Cupressus sempervirens and Pinus sylvestris, was evaluated through several enzymatic assays. The action of pollen proteases on the paracellular integrity of Calu-3, grown at the air-liquid interphase, was evaluated through a transepithelial permeability assay. Immunoblot and immunofluorescence experiments were performed to analyse the disruption of intercellular complexes. Degradation of bioactive peptides by pollen crude extracts was assessed by mass spectrometry. RESULTS: All pollen diffusates were shown to have high molecular weight proteases with serine and/or aminopeptidase activity. These proteases increased Calu-3 transepithelial permeability through disruption of transmembrane adhesion proteins: occludin, claudin-1 and E-cadherin. Moreover, they were able to degrade airway bioactive peptides and were not blocked by endogenous protease inhibitors. CONCLUSION: Pollen grains with distinct allergenic abilities release proteases that might be involved in the sensitization to a range of airborne allergens by facilitating allergen delivery across the epithelium and also contribute directly to the inflammation characteristic of allergic diseases.

Concentration of airborne pollen from Cupressaceae in Lisbon.

The concentration of airborne pollen from Cupressaceae was regularly monitored++ in Lisbon during 1997 and 1999, and the phenology of flowering cypress was studied in several species of the genus from 1992 to February 2000. Both methods showed a peak of pollen abundance during the month of February, with the airborne pollen concentration decreasing strongly to March and April. The results obtained are in accordance with the literature for the Mediterranean area, but in Lisbon the peak started and finished earlier than in other Mediterranean towns already studied.