Determination of the Sensitivity and Specificity of Prick Test Betula Verrucosa

Study Overview
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Brief Summary
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The main objective is to evaluate the concentration of allergen extract of Betula verrucosa that elicit a papule equivalent to that produced by a solution of histamine dihydrochloride 10 mg / ml in size.

Detailed Description
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Open, prospective, unblinded and non-randomized biological assay. Each patient was tested with four concentrations of allergen and with a histamine and saline solution as positive and negative controls, respectively.

Official Title
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Extract Allergen From Betula Verrucosa. Test Sensitivity and Specificity of Diagnostic in Prick Test Preparation.

Conditions
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Immune System Diseases

Intervention / Treatment
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* Biological: 10 HEP/mL Betula verrucosa allergen extract
* Biological: 25 HEP/mL Betula verrucosa allergen extract
* Biological: 50 HEP/mL Betula verrucosa allergen extract
* Biological: 100 HEP/mL Betula verrucosa allergen extract


Participation Criteria
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Eligibility Criteria
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General inclusion criteria for both groups: Positive skin prick test with the positive control (Histamine HCl at 10 mg/mL). The length of the largest diameter of the wheal induced by this control should be ≥ 3 mm. Negative skin prick test with the negative control. The length of the largest diameter of the wheal induced by this control should be < 3 mm. All ages and both genders. For the group of patients CH+ (true positive to Betula verrucosa): All these patients had a previous diagnosis of allergy to the birch pollen: A positive case history with inhalant allergy related to exposure to birch pollen. A positive skin prick test (mean wheal diameter ≥ 3 mm) when tested with a biologically standardized extract prepared from birch pollen. This preparation, from another manufacturer, was the one used in the routine in the Hospital. Positive test for specific IgE (CAP value > 0.35 IU/mL). For the group of patients CH- (true negative to Betula verrucosa): All these patients had a previous diagnosis of allergy to agents unrelated to birch pollen. A negative case history with inhalant allergy related to exposure to birch pollen or to pollen with known cross-reactivity with the birch pollen. These patients could be allergic to other pollen or other allergens, such mites. A negative prick test (largest diameter of the wheal ≥ 3 mm) when tested with a standardized extract prepared from the allergen source in question. A negative test for specific IgE (CAP value < 0.35 IU/mL) to birch pollen or to pollen with known cross-reactivity with birch pollen: Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa. Exclusion criteria for both groups: Patients that were using drugs that may interfere with the skin prick tests. Patients using the following drugs 24 hours before the test: theophylline, systemic corticosteroids. Patients in which the largest diameter of the wheal induced by the positive control was < 3 mm. Patients in which the largest diameter of the wheal induced by the negative control was ≥ 3 mm. Pregnancy, dermographism, atopic dermatitis (locally at the test site), urticaria. Patients who suffer disease in which the use of adrenaline is not allowed. Patients with any severe psychiatric disease. For the patients CH+: • Patients that received or are treated with immunotherapy with an allergenic extract of birch pollen and/or with allergen extracts with known cross-reactivity to birch pollen (Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa). For the patients CH-: Patients sensitized to pollen with demonstrated cross-reactivity with the pollen of Betula verrucosa. These pollen included Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa.

Ages Eligible for Study
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Minimum Age: 5 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Allergic patients to birch pollen<br>Allergic patients already diagnosed to be true allergic to birch pollen. A mean wheal diameter >3 mm obtained in a prick test with histamine dihydrochloride 10 mg/ml.Also presence of serum specific IgE and clinical history of symptomatology related to exposure to birch pollen. Patients of both gender aged from 5 up to 70 years. | Biological: 10 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 10 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 25 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 25 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 50 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 50 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 100 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 100 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>|
| Experimental: Non-allergic patients to birch pollen<br>Patients already diagnosed to be true non-allergic to birch pollen. Non clinical history of symptomatology related to the exposure to birch pollen. Previous skin prick test negative and absence or undetectable serum specific IgE to Betula verrucosa Patients of both gender aged from 5 up to 70 years. | Biological: 10 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 10 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 25 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 25 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 50 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 50 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>Biological: 100 HEP/mL Betula verrucosa allergen extract<br>* The investigational product contained 100 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity for 100 HEP/mL | Sensitivity for 100 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of positives that are correctly identified by the test. Sensitivity: True positives/Total disease | 1 hour | 
| Sensitivity for 50 HEP/mL | Sensitivity for 50 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of positives that are correctly identified by the test. Sensitivity: True positives/Total disease | 1 hour | 
| Sensitivity for 25 HEP/mL | Sensitivity for 25 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of positives that are correctly identified by the test. Sensitivity: True positives/Total disease | 1 hour | 
| Sensitivity for 10 HEP/mL | Sensitivity for 10 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of positives that are correctly identified by the test. Sensitivity: True positives/Total disease | 1 hour | 
| Specificity for 100 HEP/mL | Specificity for 100 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of negatives that are correctly identified by the test. Specificity: True negatives/Total no disease. | 1 hour | 
| Specificity for 50 HEP/mL | Specificity for 50 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of negatives that are correctly identified by the test. Specificity: True negatives/Total no disease. | 1 hour | 
| Specificity for 25 HEP/mL | Specificity for 25 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of negatives that are correctly identified by the test. Specificity: True negatives/Total no disease. | 1 hour | 
| Specificity for 10 HEP/mL | Specificity for 10 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test. It is the proportion of negatives that are correctly identified by the test. Specificity: True negatives/Total no disease. | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Immune System Diseases, Prick Test, Betula verrucosa