Impacts of Nitrogen Deposition in the Natural Environment on Pollen Allergy in Belgium (NITROPOL-BE)

December 2, 2024 updated by: prof. dr. Rik Schrijvers
The investigators want to study the effect of environmental nitrogen enrichment on the allergy burden in pollen-sensitized subjects.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The investigators want to study allergen-specific IgE reactivity from a cross-sectional sample of pollen-allergic patients (and negative controls) against environmental and experimental pollen samples. Following aspects will be compared:

  • To study the basophil degranulation with different amounts of pollen on fresh patient-derived basophils, to determine the concentration of pollen needed to degranulate 5% (EC5), and 50% (EC50) of basophils.
  • To study he overall intensity (quantitative), as well as IgE-mediated hyper- or hyporecognition of different fragments in the pollen samples (qualitative) in a subset of patients.
  • To associate allergic rhinoconjunctivitis and food-pollen syndrome related symptoms with reactivity to different pollen samples.

Study Type

Interventional

Enrollment (Estimated)

200

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Belgium
    • Vlaams-Brabant
      • Leuven, Vlaams-Brabant, Belgium, 3000

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Positive skin prick test for grass and/or birch pollen

Exclusion Criteria:

  • Desensitization therapy during the last two years

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Allergic subjects
All subject with positive skin prick testing for grass and/or birch pollen are assigned to this group.
Diagnostic test: Immunoreactivity testing
Blood samples will be collected and used to determine the intensity of the allergenicity of the subject toward different types of pollen. This will be done by the detection of sIgE antibodies to the pollen extracts and basophil activation testing (BAT) with pollen extracts.
Other: Healthy controls
Subjects with negative skin prick testing for grass and/or birch pollen are assigned to this group and used for as negative controls in our experiments.
Diagnostic test: Immunoreactivity testing (negative control)
Blood samples will be collected and used to determine the background activity of our immunoreactivity tests. The investigators will use samples from negative controls to demonstrate that non-allergic individuals do not react to our assays, confirming that our pollen extracts have no background reactivity. This will be done by the detection of sIgE antibodies to the pollen extracts and basophil activation testing (BAT) with pollen extracts.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Specific IgE reactivity (in-house developed) against environmental and experimental pollen samples
Time Frame: From time of inclusion to 12 months
The investigators want to measure and compare sIgE values (kUA/L) towards different pollen samples.
From time of inclusion to 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Basophil degranulation with different amounts of pollen on fresh patient-derived basophils.
Time Frame: From time of inclusion to 12 months
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.
From time of inclusion to 12 months
Overall intensity (quantitative) of IgE reactivity to pollen samples in a subset of patients.
Time Frame: From time of inclusion to 12 months
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.
From time of inclusion to 12 months
IgE-mediated hyper- or hyporecognition of different fragments in the pollen samples (qualitative) in a subset of patients.
Time Frame: From time of inclusion to 12 months
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.
From time of inclusion to 12 months

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (TNSS)
Time Frame: From time of inclusion to 12 months
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.
From time of inclusion to 12 months
Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (VAS)
Time Frame: From time of inclusion to 12 months

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
From time of inclusion to 12 months
Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (PFS)
Time Frame: From time of inclusion to 12 months
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.
From time of inclusion to 12 months
Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (EQ-5D-5L)
Time Frame: From time of inclusion to 12 months

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.
From time of inclusion to 12 months
Association of allergic rhinoconjunctivitis symptoms with reactivity to different pollen samples (WPAI + CIQ: AS)
Time Frame: From time of inclusion to 12 months

Allergy-Specific Work Productivity and Impairment (including CIQ = Classroom Impairment Questions) questionnaire (WPAI+CIQ: AS). Impaired work productivity has been associated with the severity of allergic rhinitis.

WPAI outcomes are expressed as impairment percentages, with higher numbers indicating greater impairment and less productivity, i.e., worse outcomes.

Scores:

Multiply scores by 100 to express in percentages. Percent work time missed due to allergy: Q3/Q2 Percent impairment while working due to allergy: Q4/10 Percent overall work impairment due to allergy: (Q3/Q2)+[(1-(Q3/Q2))x(Q4/10)] Percent class time missed due to allergy: Q7/Q6 Percent impairment in the classroom due to allergy: Q8/10 Percent overall classroom impairment due to allergy: (Q7/Q6)+[(1-(Q7/Q6))x(Q8/10)] Percent activity impairment due to allergy: Q9/10
From time of inclusion to 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

prof. dr. Rik Schrijvers

Collaborators

KU Leuven
Sciensano
University of Namur
Université Catholique de Louvain

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 29, 2022

Primary Completion (Estimated)

February 1, 2025

Study Completion (Estimated)

April 1, 2025

Study Registration Dates

First Submitted

November 20, 2024

First Submitted That Met QC Criteria

December 2, 2024

First Posted (Actual)

December 3, 2024

Study Record Updates

Last Update Posted (Actual)

December 3, 2024

Last Update Submitted That Met QC Criteria

December 2, 2024

Last Verified

December 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • S65184
  • B2/212/P1/NITROPOL-BE (Other Grant/Funding Number: BELSPO)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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