SCIT: Preparation of allergen extracts for therapeutic use
- Harold Nelson, MD
Harold Nelson, MD
- Professor of Medicine
- National Jewish Health
- University of Colorado Denver School of Medicine
Subcutaneous immunotherapy (SCIT) is administered differently around the world and even within the United States. Over the past few decades, professional allergy societies in the United States have made attempts to reduce variations in practice and identify best approaches. Practice parameters for SCIT have been published, and the approach described in this topic review is consistent with the American guidelines .
Terminology — An allergen immunotherapy extract is a solution of one or more allergens that is used for immunotherapy. This topic review will use the term "allergen immunotherapy extract" or "allergen extract," although other terms in use include "allergy serum," "allergen vaccine," "allergen solution," and "allergen product" .
The preparation of allergen extracts for use in SCIT, including effective doses, types of extracts, mixing of different allergens, training of compounding personnel, storage and stability, and recording of vaccine "recipes" will be discussed in this topic review. Administration techniques, schedules, and choice of allergens, as well as an overview of the manufacture of allergen extracts are reviewed separately. (See "Subcutaneous aeroallergen immunotherapy: Accelerated schedules (cluster and rush)" and "Allergen extracts: Composition, manufacture, and labeling".)
TYPES OF ALLERGEN EXTRACTS
Several types of allergen stock solutions are available from commercial sources in the United States. The allergen may be in an aqueous solution, a solution containing 50 percent glycerin, in an alum-precipitated form, or lyophilized. The manufacture of allergen extracts is reviewed in detail elsewhere. (See "Allergen extracts: Composition, manufacture, and labeling" and 'Dilutions and diluents' below.)
A specific allergen may only be available in a limited number of forms. As examples:To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
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- Plunkett G, ALK-Abello, Round Rock, Texas, personal communication. Values are based on analysis of dozens of extracts from all manufacturers in the US, 2011.
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- Cox L, Esch RE, Corbett M, et al. Allergen immunotherapy practice in the United States: guidelines, measures, and outcomes. Ann Allergy Asthma Immunol 2011; 107:289.
- Niemeijer NR, Kauffman HF, van Hove W, et al. Effect of dilution, temperature, and preservatives on the long-term stability of standardized inhalant allergen extracts. Ann Allergy Asthma Immunol 1996; 76:535.
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- Van Metre TE Jr, Rosenberg GL, Vaswani SK, et al. Pain and dermal reaction caused by injected glycerin in immunotherapy solutions. J Allergy Clin Immunol 1996; 97:1033.
- Nelson HS, Iklé D, Buchmeier A. Studies of allergen extract stability: the effects of dilution and mixing. J Allergy Clin Immunol 1996; 98:382.
- Grier TJ, LeFevre DM, Duncan EA, Esch RE. Stability of standardized grass, dust mite, cat, and short ragweed allergens after mixing with mold or cockroach extracts. Ann Allergy Asthma Immunol 2007; 99:151.
- Grier TJ, Hall DM, Duncan EA, Coyne TC. Mixing compatibilities of Aspergillus and American cockroach allergens with other high-protease fungal and insect extracts. Ann Allergy Asthma Immunol 2015; 114:233.
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- Vendors that supply media-fill tests are listed at the following site: https://www.aaaai.org/Aaaai/media/MediaLibrary/PDF%20Documents/Practice%20Management/Media-fill-test-vendors.pdf (Accessed on May 18, 2017).
- TYPES OF ALLERGEN EXTRACTS
- Standardized allergens
- Nonstandardized allergens
- CREATING A MAINTENANCE EXTRACT
- Multiple allergen immunotherapy extracts
- Dilutions and diluents
- - Diluent options
- Human serum albumin
- OTHER CONSIDERATIONS
- Cross-allergenicity among allergens
- Compatibility of allergen extracts
- Individual versus shared allergen immunotherapy extracts
- Mixing extracts in a syringe before administration
- Transport of extracts
- TRAINING FOR QUALITY CONTROL IN PREPARATION OF ALLERGEN IMMUNOTHERAPY EXTRACTS
- Clinician responsibility
- Qualifications of extract preparation personnel
- RECORDING PRESCRIPTIONS FOR ALLERGEN IMMUNOTHERAPY
- SOCIETY GUIDELINE LINKS
- SUMMARY AND RECOMMENDATIONS