Recruitment of fish allergic subjects
This study recruited subjects aged 1-18 years with reported history of IgE-mediated fish allergy from six regional hospitals in Hong Kong (HK; Prince of Wales Hospital, Queen Mary Hospital, Queen Elizabeth Hospital, Yan Chai Hospital, Princess Margaret Hospital and United Christian Hospital) and Sagamihara National Hospital in Kanagawa, Japan. The inclusion criteria include (1) subjects with convincing history of immediate fish allergy as defined by immediate allergic symptoms within 2 hours following fish ingestion within two years before recruitment and clinically diagnosed by an allergy specialist; and (2) subjects with evidence of IgE sensitization to fish by blood sIgE measurement against cod (f3), salmon (f41), tuna (f40) and/or grass carp (experimental ImmunoCAP developed in collaboration with Thermo Fisher) and/or SPT with commercial fish mix extract (ALK-Abelló). Exclusion criteria are subjects receiving maintenance immunosuppressive treatments that cannot be stopped for four weeks prior to study and who receive intravenous immunoglobulin treatment within three months. Severity of allergic symptoms to fish was calculated based on the Ordinal Food Allergy Severity Score (oFASS)20. Briefly, Grade 1 includes reactions restricted to oral cavity. Grade 2 to 5 may include oral symptoms but with other target organs affected, by which grades 2 and 3 reactions involve skin, eye/nose and/or digestive system. Involvement of larynx and/or bronchi reactions are graded 4 while grade 5 would involve cardiovascular and/or nervous systems. Participants and/or their legal guardians gave written informed consent. Ethical approvals were obtained from Joint Chinese University of Hong Kong-New Territories East Cluster Clinical Research Ethics Committee (2019.034 & 2019.612) and the Sagamihara National Hospital Ethics Committee (2019-003).