Sensitization to Allergens Clinical Trial
Official title:
Biological Standardization of D. Glomerata, L. Perenne, S. Cereale and O. Europaea Pollen Extracts in Patients Sensitized to Them.
Allergen extracts are complex mixtures of proteins and contain varying amounts of allergenic
and non-allergenic components. Many factors such as the biovariability, 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 Dactylis glomerata, Lolium
perenne, Secale cereale y Olea europaea by using this method.
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