Skin Prick Test Extracts for Dog Allergy Diagnosis Show Considerable Variations Regarding the Content of Major and Minor Dog Allergens

Clinical Institute for Medical and Chemical Laboratory Diagnostics, Medical University of Vienna, Vienna, Austria.
International Archives of Allergy and Immunology (Impact Factor: 2.67). 02/2011; 154(3):258-63. DOI: 10.1159/000321113
Source: PubMed


Commercial skin prick test (SPT) extracts used for the diagnosis of dog allergy are prepared by extracting allergens from natural sources, e.g. dog hair and dander. Due to different starting material and extraction methods used, it is likely that extracts differ regarding their allergen contents.
The total protein content and composition of dog SPT extracts from 5 European manufacturers were compared by silver-stained SDS-PAGE. Specific antibody probes were generated to detect major and minor allergens in each extract by immunoblotting. Additionally, sera of patients suffering from dog allergy were used to detect dog allergens in SPT extracts.
SPT extracts showed a 20-fold variation regarding the total protein content. The contents of the major dog allergen Can f 1 and of Can f 2 varied considerably between the extracts. In one of the extracts, neither Can f 1 nor Can f 2 could be detected by immunoblotting. The contents of the minor dog allergen Can f 3, albumin, also showed great variability. In one of the dog SPT extracts, the presence of human serum albumin (HSA) was detected with HSA-specific antibodies.
The observed variability of commercial dog SPT extracts regarding their allergen contents likely has a negative influence on the accuracy of diagnosis of dog allergy.

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Available from: Mirela Curin, Oct 21, 2014
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    • "In our series, Can f 1, 2 and 3 are minor allergens, while Can f 5 is responsible for up to 67% of sensitizations and, importantly 37% of our patients are not sensitized either to Can f 1, 2 or 3 but only to Can f 5 [9]. There is a high variability between commercial dog extracts regarding their allergen contents [10], and Can f 5 is poorly represented. It would not seem appropriate to indicate specific immunotherapy to dog extract in patients monosensitized to Can f 5 until this (and possibly other) major allergen content is guaranteed in the therapeutic extract. "
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    • "The quality of an allergen extract is influenced by the production process but also by the source material, which may cause considerable variations. In fact, several studies have shown that the allergen content of extracts varies between different manufacturers as well as between batches.15,16 Standardization protocols to determine the potency of an extract start with skin prick tests on selected sensitized patients. "
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    • "Ideally, allergen extracts should contain stable and sufficient amounts of all relevant allergenic proteins. In reality, however, this is often not the case, as the content and quality of extracts is dependent on the source material, which shows natural variations, thus causing variability [10–13, 14•]. This issue remained unresolved until recombinant allergens became available [15, 16]. "
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