Impacts of Nitrogen Deposition in the Natural Environment on Pollen Allergy in Belgium

Specific IgE reactivity (in-house developed) against environmental and experimental pollen samples

The investigators want to measure and compare sIgE values (kUA/L) towards different pollen samples.

Basophil degranulation with different amounts of pollen on fresh patient-derived basophils.

The investigators want to measure and compare basophil degranulation with different pollen extracts on fresh patient-derived basophils. The investigators will use %CD63+ basophils as measure for basophil reactivity and sensitivity. The investigators will compare this between different pollen samples.

Overall intensity (quantitative) of IgE reactivity to pollen samples in a subset of patients.

The investigators will use an immunoblot to compare IgE mediated reactivity toward different pollen samples. Quantitatively, the investigators will compare band intensity (mean gray value) between different samples.

IgE-mediated hyper- or hyporecognition of different fragments in the pollen samples (qualitative) in a subset of patients.

The investigators will use an immunoblot to compare IgE mediated reactivity toward different pollen samples. Qualitatively, the investigators will compare presence of bands between samples.

Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (TNSS)

The Total Nasal Symptom Score (TNSS) is the sum of scores for each of nasal congestion, sneezing, nasal itching, and rhinorrhea at each time point, using a four point scale (0-3), where 0 indicates no symptoms, a score of 1 for mild symptoms that are easily tolerated, 2 for awareness of symptoms which are bothersome but tolerable and 3 is reserved for severe symptoms that are hard to tolerate and interfere with daily activity. TNSS is calculated by adding the score for each of the symptoms to a total out of 12.

Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (VAS)

The rhinitis severity Visual analogue scale (VAS) is used to evaluate the overall severity of the rhinitis symptoms. The participant is asked to answer the several questions on: "How troublesome are your symptoms" on a 100mm VAS from 0 ('not troublesome') to 100 ('worst thinkable troublesome'). Based on their score on the VAS, the severity of rhinosinusitis can be divided into 3 categories as follows: Mild = VAS \<20 mm Moderate = VAS 20-50 Severe = VAS \>50

Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (PFS)

Pollen-food syndrome (PFS) validated diagnostic questionnaire evaluates presence and severity of cross-reactivity. The diagnostic questionnaire and algorithm is a practical and robust tool, which enables rapid identification, and therefore management, of individuals with PFS who experience rhino-conjunctivitis symptoms in the birch pollen season. Evaluate association of cross-reactivity with reactivity to different pollen samples.

Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (EQ-5D-5L)

Stress and well-being: evaluate impact on patients life - Quality of life (EuroQol 5 Dimensions, 5 Levels = EQ-5D-5L). Will be evaluated according to the standard guidelines. A worse rhinitis control and a worse asthma control are associated with higher EQ-5D-5L levels, particularly regarding pain/discomfort and activity impairment. Worse rhinitis control is associated with worse anxiety/depression, and poor asthma control with worse mobility. The descriptive system comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4) and extreme problems (5). The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the 5 dimensions. The digits for the 5 dimensions can be combined into a 5-digit number that describes the patient's health status.