PROJECT AMBASSADOR OF December 2014
Dr. Miguel González Muñoz / Servicio Madrileño de Salud, Spain
Dr. Miguel González Muñoz is the leader of workpackage 5, which deals with hazard characterization. The WP is aimed at detecting anisakids allergens in fishery products from different regions and at characterizing the cellular and humoral immune responses they provoke. This WP has also the objective of determining the allergic capacity of parasites belonging to the family Anisakidae but different from Anisakis spp.
About Miguel González Muñoz
Dr. González Muñoz has a degree in Veterinary and a degree in Biology. He has been working as a specialist in Immunology at the Hospital Carlos III (Madrid) since 1991. He has 47 publications in immunology area. Currently his work is focused on the characterization of type I hypersensitivity responses to different allergens. He has been working in Anisakis spp. allergy since 2005 and has published 15 articles on the characterization of specific immune response to Anisakis spp. He has a patent on detection of Anisakis antigens in food.
Why the Anisakis allergy is so difficult to diagnose?
The diagnosis of a food allergy with an immediate hypersensitivity reaction is usually uncomplicated because allergic symptoms occur immediately after consumption of the suspected food. On the contrary, in case of sensitization to Anisakis, the diagnosis in clinical practice is more difficult because allergic symptoms generally appear up to 24 hours from the intake of the parasitized fish. Furthermore, it is troublesome in some cases to identify the episode when people are exposed for the first time to live Anisakis and then parasitized and sensitized, or the symptoms can be wrongly attributed to another agent. Therefore, clinical diagnosis of Anisakis allergy needs confirmation with prick test and specific IgE detection.
Why do not traditional diagnostic methods work?
Skin allergy test and specific IgE detection are the tests usually carried out to confirm the diagnosis of Anisakis allergy. The laboratory diagnosis of Anisakis allergy is based on the detection of specific IgE in people showing allergic reactions after eating raw or undercooked fish. In order to determine the specific IgE, a commercial system is generally used where patients’ sera are incubated with an Anisakis crude extract. The problem with this diagnostic method is the cross-reactivities between Anisakis and other related parasites and, also, other non-related invertebrate organisms such as mites, insects or crustaceans. That means that people allergic to these other allergens can show false positive IgE against Anisakis.
In the Parasite project more specific diagnostic methods are planned to be developed, will they be easy to implement? To what extent?
In the project PARASITE we aimed to characterize the human immune responses to Anisakis as well as to identify new parasite allergens. Both objectives are expected to contribute to develop more specific diagnostic methods. The characterization of the allergens and the immune response would allow selecting multiple clinically relevant allergens to test the presence of IgE in the patient’ serum in a more specific way than the current available methods. There are already platforms designed to quantify specific IgE to multiple allergens in other allergies, so it can be presumed that it will be easy to implement this system for Anisakis allergy also.
Once the diagnostic methods are improved, can it be expected that more effective treatments will be further on developed?
Once the allergic symptoms have been treated and resolved, patients are given some dietary recommendations. Dietary guidelines vary. Some patients need a strict diet with complete avoidance of fish for a time period, while other tolerate fish consumption provided that fish has been subjected to a treatment able to kill the parasite, e.g. freezing. The serological characterization of the allergic response using multiple allergens would aid to personalize diets based on individual reactivity differences.
What components of parasites are responsible for the allergic reactions? Are they inactivated through common processing such as cooking or freezing?
The sensitized patients recognize several different parasite allergens because they can be exposed to A. simplex components from different sources: excretory/secretory fluids, somatic, and cuticular antigens, as a result of tissue penetration and subsequent degeneration of the larvae, what leads to exposure to all parasite’s antigens. On the other hand, they can be exposed also to cuticular and somatic antigens from dead larvae contained in food, in which case excretory/secretory antigens would be present only in minimal quantities. Generally, the responses to parasite excretory/secretory antigens tend to be stronger than those induced by somatic antigens. It has been shown that some of these allergens are stable to long-term freezing and to different high temperature treatments and, therefore, active allergens can be present in processed food and may constitute a risk for some sensitized patients.