How the database has been constructed

In order to ensure the credibility of the information in this website the entries have been subjected to a refereeing process. Experts drawn from the InformAll partnership and the wider scientific community have checked the entries to ensure their validity. See refereeing details

Version history

General Information

This page contains the fields: Name, Scientific Name, Occurrence, Allergy Information, Other Information and Taxonomic Information. There is also an image of the food or organism.

Occurrence: This contains some information about which foods are most likely to contain this allergenic food. For some foods, a link is included to tables supplied by the InformAll partner Swiss Quality Testing Services (http://www.sqts.ch/) and kindly translated into English by Dr Birgit Teucher (Institute of Food Research). However, only the manufacturer's labelling supplies reliable information on the presence or absence of the allergenic food.

Allergy Information: This contains a short summary of the clinical information page, hopefully written in clear, concise language. For many of the most important allergenic foods longer summaries written by expert clinicians are available as clickable links. These foods are milk, egg, fish, crustaceans, peanut, soy, wheat, corn (maize), apple, kiwi, hazelnut, almond, walnut, sesame, celery, mustard, spices, peach and banana. We have also supplied an extended summary for molluscs.

Taxonomic Information:  This normally supplies links to taxonomic databases such as NEWT or ITIS  but may also indicate when more than one species can be the origin of the allergenic food.

Clinical Information

Further information on the methods used for diagnosis of food allergies can be found at www.foodallergens.info/consumers

Clinical history: this section contains general information on the symptoms that have been reported following consumption of a particular food. It also includes

• Estimates of the number of studies reported for a given food
• The number of patients described in a particular studies - this can be difficult to determine since several studies can include patients in common and hence individuals counted twice. As a consequence, approximate numbers are given, as ranges.

Skin prick test (SPT): this section includes an estimate of the number of studies and patients involved in these studies, as for the clinical history section. It also includes information on the food, extract or allergen used for SPT, and the SPT protocol (when available), together with a summary of the SPT results.

IgE assay: This section details the studies used to determine the presence of IgE in serum of allergic individuals to specific foods or purified allergens. It includes information on the number of studies, type of methods used to determine IgE, the food extract or type of allergen used, and numbers of patients.

Immunoblotting: this section contains information on the methods used to separate proteins, the method used for detection of IgE binding, and results. These fields give information on the molecules in food extracts that may be involved in IgE-mediated diseases. This is included even for those foods for which the individual allergens have yet to be characterised if allergen masses have been determined.

Oral provocation: this section contains information on the number of studies that have used oral provocation to confirm whether an individual has a food allergy. It includes information on the food used, whether the oral challenges were performed blind (i.e. where the problem food is disguised) or not, the number of patients, any dose response information, and the symptoms including details of how many patients reacted. There is some overlap with the "clinical history" section as the symptoms following an oral challenge are listed in both.

IgE cross-reactivity and polysensitisation: this section addresses the associations between allergies to different foods, pollens and latex.

Other clinical information: this section may contain additional information that does not appear elsewhere.

Biochemical information

This section includes an entry for each allergen identified in any given food. Closely related allergens have been combined into a single record, for example Ara h 3 and Ara h 4.

Allergen name and designation: the common names given in the literature are cited together with the designation (major or minor) following the standard IUIS definitions, where available.

Protein family: this field defines the family of related proteins to which an allergen belongs and usually supplies a link to the PFAM database of protein families.

3D structure: Where the 3D-structure of the family is known, the information can be found via this link or from the UniProt link given in accession codes. The 3D structure accession codes field is thus only used to provide a link to the Protein Data Bank for a structure of the allergen itself.

Allergen sequence: Where allergen sequences have been deposited, a hyperlink has been made where possible to SwissProt (UniProt) because of the extensive information available in those entries. For sequences not included in SwissProt, links to GenBank have been created. For some allergens the links are to fragments, or even to collections of peptides, which may appear at first glance to be a single sequence but are not contiguous. Allergens for which many sequences have been identified (e.g. wheat alpha-gliadins) only a few representative sequences have been listed. Some sequences are listed that are probably potential allergens, but also not normally eaten (e.g. apple Mal d 1 homologues found in leaves).

Allergen mass: The calculated masses are derived from the sequence and may be that from the complete sequence, including an N-terminal methionine and possibly other sequences that may be removed during maturation. Notes may be added such as "mature" to indicate that these sequences are not included. In general, the calculated mass does not include modifications such as glycosylation. The experimental masses are generally derived from immunoblotting and SDS-PAGE analysis. Some masses are derived from mass spectroscopy; this is normally indicated. However, if an experimental mass such as 17181 Da is given, the precision implies that it is derived from mass spectroscopy. The oligomeric mass may either be given from experiment or from knowing that, for example, 7S storage proteins are trimers. Additional information on allergen properties, function in plant and purification has also been included.

List of allergens: Although not designed as a allergen sequence database, a table of allergens has been extracted from both the online database and draft entries under preparation.

References

Most of the references are for peer reviewed articles or reviews although some book chapters and a few abstracts are cited. Some references are listed separately as recent reviews of the clinical information and hopefully more will be added in time.

The references are normally given in the form "Varjonen et al. (1996) [911]" with the number in square brackets identifying uniquely the reference. These numbers are in no special order and there are gaps in the sequence. Where a PubMed record is available, expressions such as [911] are direct links to PubMed, which provides an abstract and often another link to the full text.

Many references have been added from PubMed (although ISI's Web of Science and the Biosis Database have also been searched). The use of PubMed as a source has the disadvantage that some names are changed by removal of accents or otherwise corrupted, and only two initials are given. We have tried to correct such errors but some remain.

The major online allergen databases

Allergen databases have been created for a variety of functions. This is reflected both in the type of data available from individual databases and in their criteria for accepting allergens. Thus databases can be used to test if a sequence is "related" to an allergen in the database; to test if a sequence is "related" to an epitope in the database; to extract a list of allergens or epitopes; or finally to find information about individual allergens.

Databases aimed at supplying lists of sequences are significantly different from databases intended to collect information on individual allergens, and are designated as one or the other below. However, there is some overlap as "information databases" will normally also contain links to the sequences. The one database that does not fit into these categories is the Allergen Nomenclature Database of the International Union of Immunological Societies (IUIS) Allergen Nomenclature Sub-Committee (http://www.allergen.org). This database is intended to provide a central resource for ensuring that allergen designations are uniform and consistent. Although literature citations and database accession numbers are listed, there are no direct links to the sequence resources.

There is great variety in the databases above. This arises because different approaches and philosophies result in significantly different databases, both in terms of design and functionality. However, this emphasises the value of multiple options for online searching. Multiple searches also help to minimise the effects of possible detailed errors and inconsistencies (Brusic V, Millot M, Petrovsky N, Gendel SM, Gigonzac O, Stelman SJ. (2003) Allergen databases. Allergy 58(11):1093-1100; Gendel SM, Jenkins JA. (2006) Allergen sequence databases. Mol Nutr Food Res. 50(7):633-637).

The INFORMALL database has been developed with funding from the European Union (Communicating about Food Allergies – Information for Consumers, Regulators and Industry - Informall, QLRT-2001-02284) to provide a credible source of information on allergenic food materials of both plant and animal origin.