IMMUNOLOGIC/DIAGNOSTIC TESTS IN ALLERGY (M CHAPMAN AND A POMÉS, SECTION EDITORS)
Diagnosis of Allergy to Mammals and Fish: Cross-Reactive vs.
Marianne van Hage
The Author(s) 2017. This article is an open access publication
Purpose of Review Allergen extracts are still widely used in
allergy diagnosis as they are regarded as sensitive screening
tools despite the fact that they may lack some minor allergens.
Another drawback of extracts is their low specificity, which is
due to the presence of cross-reactive allergens. Progress in
allergen identification has disclosed a number of allergenic
molecules of homologous sequence and structure which are
present in different animal species. This review summarizes
recent advances in mammalian and fish allergen identification
and focuses on their clinical relevance.
Recent Findings Serum albumins and parvalbumins are well-
known animal panallergens. More recently several members
of the lipocalin family were found to be cross-reactive
between furry animals whereas in fish, additional allergens,
enolase, aldolase and collagen, were found to be important
and cross-reactive allergens. New epidemiological studies
have analysed the prevalence and clinical relevance of
mammalian and fish components.
Summary Primary sensitization can be distinguished from
cross-sensitization by using marker allergens. Although substan-
tial progress has been made in allergen identification, only few
markers are commercially available for routine clinical practice.
Keywords Allergy diagnosis
Furry animal allergy
Allergy diagnosis is still mainly based on allergen extracts.
Skin prick test solutions as well as the majority of assays used
for in vitro diagnosis are composed of extracts. They are
relatively easy to produce and although they are difficult to
standardize, they are essential diagnostic tools. However, they
also have some serious drawbacks such as variable allergen
content, underrepresentation of minor allergens, potential con-
tamination by other allergen sources and very importantly,
cross-reactivity among allergens present in different extracts
which precludes a differential diagnosis . Single allergen
molecules or components have found their way into IgE-
based diagnostics, but their proven utility in allergy diagnosis
still needs to be implemented in daily clinical practice.
The last two decades have brought enormous progress in
allergen identification and characterization. About 870 aller-
gens are registered in the World Health Organization and
International Union of Immunological Societies (WHO/
IUIS) Allergen Nomenclature Sub-Committee database
(http://www.allergen.org) based on evidence of allergenicity
and many more have been described in scientific publications.
We are now aware of the fact that homologous proteins are
present in different allergen sources. The pathogenesis-related
(PR) protein family 10, the non-specific lipid transfer proteins
(nsLTP) and profilins are well-known panallergens in pollen
and plant foods [2••]. Tropomyosin is the hallmark of IgE
cross-reactivity among invertebrates such as shellfish, mol-
luscs and arthropods [2••]. In vertebrates, the only known
panallergens are parvalbumins, the major fish allergens, and
This article is part of the Topical Collection on Immunologic/Diagnostic
Tests in Allergy
* Christiane Hilger
Department of Infection and Immunity, Luxembourg Institute of
Health, 29, rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg
Immunology and Allergy Unit, Department of Medicine Solna,
Karolinska Institutet, and Karolinska University Hospital,
Curr Allergy Asthma Rep (2017) 17:64