Differences in omega-5-gliadin allergy: East versus West

Abstract

Background: Omega-5-gliadin (O5G) allergy, also known as wheat-dependent exerciseinduced anaphylaxis, is commonly reported in the Western, but not Asian, populations. Although significant differences in O5G allergy presentation across different populations are likely but there have been no previous reports on this important topic. Objective: To report on the prevalence and characteristics of O5G allergy in Hong Kong (HK) compared with the United Kingdom (UK). Methods: O5G allergy patients attending Queen Mary Hospital (HK cohort), and Guy's and St Thomas' Hospital, London (UK cohort) were studied and compared. Results: A total of 46 O5G allergy patients (16 HK; 30 UK) were studied. In the HK cohort, 55% of all patients previously labeled as "idiopathic anaphylaxis" were diagnosed with O5G allergy. Exercise was the most common cofactor in both cohorts, followed by alcohol and nonsteroidal anti-inflammatory drugs (NSAID). A higher proportion of the HK cohort reported NSAID as a cofactor (13% vs. 0%, p = 0.048). In the HK cohort, more patients presented with urticaria and cardiovascular manifestations (100% vs. 77%, p = 0.036; 100% vs. 70%, p = 0.015, respectively); the range of presentation was more diverse in the UK cohort. In HK fewer patients adhered to wheat avoidance (50% vs. 87%, p = 0.007) and more patients avoided cofactors only (44% vs. 10%, p = 0.008). Conclusion: O5G allergy appears relatively underdiagnosed in HK. Urticaria and cardiovascular manifestations are common; NSAID plays an important role as a cofactor and patients are less concordant with dietary avoidance measures than in the Western population.

<p>Clinical Characteristics and Proposed Wheat-Cofactor Challenge Protocol with a High Diagnostic Yield in Adult-Onset IgE-Mediated Wheat Allergy</p>

“…44 The mechanistic link is supported by a murine model in which allergen sensitization occurred in barrier-impaired skin, mediated by keratinocyte thymic stromal lymphopoietin. 45 SPTs using commercial wheat extract generally yielded unsatisfactory results, similar to other studies, 18,46 whereas SPTs using in-house glutenin and gliadin extracts yielded a higher (>80%) positivity rate, similar to Thai wheatallergic children patients. 27 Although wheat extracts for skin testing are commercially available, the preparation, especially as an aqueous solution, may not be sensitive for the diagnosis because some major wheat allergens are alcohol-soluble.…”

Increasing incidence of anaphylaxis in Hong Kong from 2009 to 2019 -- discrepancies of anaphylaxis care between adult and pediatric patients

“…Identification of potential ethnic-or population-specific modulators may elucidate novel protective or pathomechanisms of anaphylaxis. For example, differences in susceptibility to specific co-factors or adherence to allergen avoidance among different ethnicities have been implicated 16 . Such findings would be invaluable to inform future allergy prevention or treatment strategies both locally and internationally.…”

“…This is particularly important when there is a time lag between the allergic or anaphylaxis episode and subsequent allergy consultation. The alarmingly low rate of AAI prescription in Hong Kong was, however, worrisome as more than 10% of adult patients with anaphylaxis did not have an identifiable cause and were reported to have lower adherence to dietary avoidance compared to Western cohorts 16 . Our findings therefore heed for an urgent call to improve allergy resources and physician education for anaphylaxis.…”

Hong Kong Anaphylaxis Consortium Consensus Statements on prescription of adrenaline autoinjectors in the acute care setting

“…Similar to Western populations, the estimated incidence rate of anaphylaxis in Hong Kong is around 3.57 per 100,000 person-years and admissions for anaphylaxis have increased significantly [ 13 ]. However, only a minority of patients in Hong Kong diagnosed with anaphylaxis are prescribed AAInj despite the recommendation to provide AAInj following anaphylaxis in the Hospital Authority's Handbook of Internal Medicine [ 14 15 ]. Despite a continued increase in anaphylaxis incidence, fewer than 15% of anaphylaxis survivors were prescribed AAInj prior to hospital discharge between 2009 and 2019 [ 16 ].…”

“…Traditional Chinese medicine has been implicated to trigger anaphylaxis [ 17 ]. Clinical presentations and patient adherence to allergen avoidance also differ from other populations [ 15 ]. Remoteness from emergency care is less of a concern with the HK Fire Service Department's service pledge of just 12 minutes from time of call to arrival of an ambulance [ 20 ].…”