AITHM James Cook University

10 September 2019

Hooked on fish allergies

JCU PhD researcher, Thimo Ruethers, is already a big fish in his field of study – unravelling the complex causes of fish allergies and identifying better ways to diagnose and manage this potentially deadly immune disease, which afflicts millions globally.

Based on the world’s largest ever assembled group of fish allergy study participants – 100 patients from the Children’s Hospital at Westmead, in Sydney – his research is already garnering both national and international attention.

This year, the medical scientist reached the national finals of FameLab, a world-wide science communication competition designed to showcase top young researchers, and also won a prize for his presentation at the European Academy of Allergy and Clinical Immunology Congress (EAACI) in Lisbon, which attracted almost 9000 delegates.

In 2018, he took to the stage at the EAACI congress in Munich, the Asia Pacific Association of Allergy, Asthma and Clinical Immunology conference in Bangkok, the Australasian Society of Clinical Immunology and Allergy conference in Canberra, as well as the International Conference on Food Analyses and the Food Allergen Symposium, both in Melbourne.

In between sharing his research findings to date with keenly interested fellow allergy investigators around the world, Mr Ruethers is back in the lab in Townville, where he is now putting the finishing touches to his pioneering PhD thesis, under the guidance of JCU Molecular Allergy Research Laboratory leader, Professor Andreas Lopata.

Despite the fact that seafood, a popular item in Australian diets, is the number one cause of food allergy-related deaths in this country – as well as most other countries in the Asia-Pacific region and the USA – limited research has been undertaken in this part of the world. Most existing studies focus on allergies to fish species found in Europe and North America.

Mr Ruethers had to start virtually from scratch. Over the past four years, he has evaluated the allergenicity (ability to trigger an allergic reaction) of more than 100 fish species and other related vertebrates – with impressive results.

“Previously, there were five recognised fish allergens in the world. We have now identified an additional eight allergens and registered them with the World Health Organisation,” he said.He has now pinpointed exactly which fish species trigger allergic reactions in study participants, by testing their blood samples in the laboratory. However, his success has led to the revelation that conventional, commercial allergy skin prick tests, administered to patients by clinicians, contain potentially fatal flaws.

“We discovered that the amount of allergens in commercial skin prick test preparations varies greatly and in some cases, major allergens can’t be detected at all. This means many of these tests may indicate someone is not allergic to fish, when they actually are. But there are no regulations governing the standards of these diagnostic preparations,” he said.

 “We are advocating for comprehensive blood tests to become the primary diagnostic tool for fish allergies. We are now collaborating with European biotech companies to develop a point-of-care device which will help millions of patients worldwide.”

Mr Ruether’s in-depth analysis has also revealed the dangers of cross-reactivity; more than half of the tested patients were allergic to crocodile meat, even though none had ever tried it. Crocodiles and other reptiles share common evolutionary ancestry with fish, so the human immune system often does not differentiate between them.

But there is an upbeat conclusion to his fish tale. He has identified safe alternatives for fish allergy sufferers who still hanker for seafood.

“Patients who are allergic to bony fish often have low or no reactivity to cartilaginous fish, such as sharks and rays. Flake is a trading name for sharks, including gummy shark. It’s caught sustainably and you can find it at most fish and chip shops and fish mongers,” he said.

This research finding has global ramifications far beyond personal dietary preferences. 

“If we look at the future of feeding the world in a sustainable way, aquaculture is one of the key elements, so addressing fish allergies is of major importance in liberating the diet of patients and ensuring intake of high-value proteins,” he said.

 

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