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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    ABSTRACT: The knowledge on molecular allergy diagnosis is continuously evolving. It is now time for the clinician to integrate this knowledge and use it when needed to improve the accuracy of diagnosis and thus provide more precise therapeutic and avoidance measures. This review does not intend to comprehensively analyze all the available allergen molecules, but to provide some practical clues on use and interpretation of molecular allergy diagnosis. The potential role of component resolved diagnosis in circumstances such as the indication of allergen immunotherapy, pollen polysensitization, food allergy, latex allergy or anaphylaxis, is assessed. Interpreting the information provided by molecular allergy diagnosis needs a structured approach. It is necessary to evaluate single positivities and negativities, but also to appraise "the big picture" with perspective.
    09/2014; 4(1):28. DOI:10.1186/2045-7022-4-28
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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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    ABSTRACT: Presently, allergy diagnosis and therapy procedures are undergoing a transition phase in which allergen extracts are being step-by-step replaced by molecule-based products. The new developments will allow clinicians to obtain detailed information on sensitization patterns, more accurate interpretation of allergic symptoms, and thus improved patients' management. In this respect, recombinant technology has been applied to develop this new generation of molecule-based allergy products. The use of recombinant allergens allows full validation of identity, quantity, homogeneity, structure, aggregation, solubility, stability, IgE-binding and the biologic potency of the products. In contrast, such parameters are extremely difficult to assay and standardize for extract-based products. In addition to the possibility of bulk production of wild type molecules for diagnostic purposes, recombinant technology opened the possibility of developing safer and more efficacious products for allergy therapy. A number of molecule-based hypoallergenic preparations have already been successfully evaluated in clinical trials, bringing forward the next generation of allergy vaccines. In this contribution, we review the latest developments in allergen characterization, molecule-based allergy diagnosis, and the application of recombinant allergens in therapeutic setups. A comprehensive overview of clinical trials using recombinant allergens as well as synthetic peptides is presented.
    Yonsei Medical Journal 07/2014; 55(4):839-52. DOI:10.3349/ymj.2014.55.4.839 · 1.29 Impact Factor
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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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    ABSTRACT: Opinion statement Allergic diseases are among the most common health issues worldwide. Specific immunotherapy has remained the only disease-modifying treatment, but it is not effective in all patients and may cause side effects. Over the last 25 years, allergen molecules from most prevalent allergen sources have been isolated and produced as recombinant proteins. Not only are these molecules useful in improved allergy diagnosis, but they also have the potential to revolutionize the treatment of allergic disease by means of immunotherapy. Panels of unmodified recombinant allergens have already been shown to effectively replace natural allergen extracts in therapy. Through genetic engineering, several molecules have been designed with modified immunological properties. Hypoallergens have been produced that have reduced IgE binding capacity but retained T cell reactivity and T cell peptides which stimulate allergen-specific T cells, and these have already been investigated in clinical trials. New vaccines have been recently created with both reduced IgE and T cell reactivity but retained ability to induce protective allergen-specific IgG antibodies. The latter approach works by fusing per se non-IgE reactive peptides derived from IgE binding sites of the allergens to a virus protein, which acts as a carrier and provides the T-cell help necessary for immune stimulation and protective antibody production. In this review, we will highlight the different novel approaches for immunotherapy and will report on prior and ongoing clinical studies.
    03/2014; 1(1):91-106. DOI:10.1007/s40521-013-0006-5
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