Determination of Biological Activity of Three Allergen Extracts
Condition: Hypersensitivity
MeSH terms: Hypersensitivity
Study type: Interventional
Phase: Phase 2

Summary: 
      Allergen extracts are complex mixtures of proteins and contain varying amounts of allergenic
      and non-allergenic components. Many factors such as the variability, differences in
      extraction process and subsequent handling of allergens can affect the final composition,
      potency, and stability of allergen preparations. Genetic diversity of affected people adds
      another level of complexity. In order to control variability and to achieve consistency and
      reproducibility for optimal safety and sensitivity/specificity, it is essential to
      standardize the amount of allergen used in prick tests. Therefore, the system for biological
      standardization mainly used in Europe still is the biological calibration of in-House
      Reference Preparations (IHRP). The method has been adopted by the Nordic Council on Medicines
      as the Nordic Biological Unit, Histamine Equivalent Potency (HEP) or Skin Prick Test (SPT)
      value. The aim of this procedure is to estimate the biological activity of allergen extracts.
      The activity of an allergen extract is defined as 1 SPT per ml, when the extract provokes a
      specific skin reaction with a wheal of the same size as a wheal provoked by reference
      histamine at a concentration of 10 mg/ml, when both solutions are administrated using the
      same technique (prick testing) on at least 20 individuals who are sensitized to the allergen
      concerned.

      The present study aims to standardize the allergen extracts of Artemisia vulgaris, Platanus
      acerifolia, Dermatophagoides farinae by using this method.
    

Detailed description: 
      The present study aims to standardize the allergen extracts of Artemisa vulgaris, Platanus
      acerifolia and Dermatophagoides farinae by using this method. Standardized extracts will then
      be used for diagnostics and treatment of allergies as mentioned above.
    

Intervention name(s): Skin Prick Test - Atopic subjects; Skin Prick Test - Non Atopic subjects; Skin Prick Test - Allergic subjects
Intervention type(s): Biological; Biological; Biological
Intervention description(s): Skin prick test of 4 concentrations of each allergenic source, together with a positive and negative control, using 10 mg/ml histamine dihydrochloride solution and a glycerinated phenol saline solution, respectively, will be tested in every patient in duplicate on the volar surface of the forearm. Assessment of the wheal size after 15 minutes.; Skin prick test of 4 concentrations of each allergenic source, together with a positive and negative control, using 10 mg/ml histamine dihydrochloride solution and a glycerinated phenol saline solution, respectively, will be tested in every subjects in duplicate on the volar surface of the forearm. Assessment of the wheal size after 15 minutes.; Skin prick test of 4 concentrations of each allergenic source, together with a positive and negative control, using 10 mg/ml histamine dihydrochloride solution and a glycerinated phenol saline solution, respectively, will be tested in every patient in duplicate on the volar surface of the forearm. Assessment of the wheal size after 15 minutes.
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Allergy