Comprehending the allergen repertoire of shrimp for precision molecular diagnosis of shrimp allergy.

BACKGROUND: Clinical management of shrimp allergy is hampered by the lack of accurate tests. Molecular diagnosis has been shown to more accurately reflect the clinical reactivity but the full spectrum of shrimp allergens and their clinical relevance are yet to be established. We therefore sought to comprehend the allergen repertoire of shrimp, investigate and compare the sensitization pattern and diagnostic value of the allergens in allergic subjects of two distinct populations. METHODS: Sera were collected from 85 subjects with challenge-proven or doctor-diagnosed shrimp allergy in Hong Kong and Thailand. The IgE-binding proteins of Penaeus monodon were probed by Western blotting and identified by mass spectrometry. Recombinant shrimp allergens were synthesized and analyzed for IgE sensitization by ELISA. RESULTS: Ten IgE-binding proteins were identified, and a comprehensive panel of 11 recombinant shrimp allergens was generated. The major shrimp allergens among Hong Kong subjects were troponin C (Pen m 6) and glycogen phosphorylase (Pen m 14, 47.1%), tropomyosin (Pen m 1, 41.2%) and sarcoplasmic-calcium binding protein (Pen m 4, 35.3%), while those among Thai subjects were Pen m 1 (68.8%), Pen m 6 (50.0%) and fatty acid-binding protein (Pen m 13, 37.5%). Component-based tests yielded significantly higher area under curve values (0.77-0.96) than shrimp extract-IgE test (0.70-0.75). Yet the best component test differed between populations; Pen m 1-IgE test added diagnostic value only in the Thai cohort, whereas sensitizations to other components were better predictors of shrimp allergy in Hong Kong patients. CONCLUSION: Pen m 14 was identified as a novel shrimp allergen predictive of challenge outcome. Molecular diagnosis better predicts shrimp allergy than conventional tests, but the relevant component is population dependent.

Changing pattern of pediatric anaphylaxis in Hong Kong, 2010-2019.

BACKGROUND: Anaphylaxis is a significant health burden in most Western countries, but there are little published data on the incidence and pattern of anaphylaxis in Asia. We aim to determine the incidence rate and pattern of anaphylaxis over the past decade among the pediatric population in Hong Kong. METHODS: Medical records of patients presenting with allergy-related symptoms during the period 2010 to 2019 were examined. Pediatric patients aged below 18 years who fulfilled the diagnostic criteria for anaphylaxis laid out by the NIAID/FAAN were analyzed. Incidence rates were calculated using population statistics as the denominator. All information pertaining to the anaphylaxis events and patients' characteristics was retrieved using standardized data collection forms. RESULTS: The overall 10-year estimated incidence of anaphylaxis was 9.76 per 100,000 person-years, with a rising trend of anaphylaxis incidence across time. Food-induced anaphylaxis accounted for the majority of hospital presentations, of which peanut and shellfish were the top food triggers in our population. Majority of anaphylaxis episodes were of Grade 4 severity, and young age was a significant predictor of severe allergic reactions. Half of the anaphylaxis episodes were misdiagnosed and adrenaline was only utilized in 42.2% of cases, of which 9.4% were administered adrenaline prior to hospital arrival. CONCLUSIONS: An increasing trend of anaphylaxis incidence over the past decade is evident in Hong Kong children, with a discrepantly low accuracy in diagnosis and suboptimal management of anaphylaxis. There is a pressing need to heighten public and physicians' awareness of the distinctive features of anaphylaxis in the pediatric age-group.

Myocardial oedema in an 8-year-old Chinese boy with Idiopathic systemic capillary leak syndrome.

BACKGROUND: Idiopathic systemic capillary leak syndrome (ISCLS) is rare, and there has been about 32 cases reported in children worldwide since this disorder was first described in 1960. Clinical guidelines on the management approach stemming from robust scientific evidence are lacking. This case report presents the first reported paediatric case of severe ISCLS with significant myocardial oedema and emphasizes this disease's impact on a child's cardiac function. CASE PRESENTATION: A Chinese boy had his first attack of severe hypovolaemic shock that responded to fluid resuscitation when he was 6 years of age. His second attack developed at 8 years of age. He was then transferred to our cardiac unit for refractory hypotensive shock. The patient's echocardiogram revealed ventricular wall thickening with significant cardiac dysfunction requiring extracorporeal membrane oxygenation support. Subsequently, he made a full recovery, including his myocardial wall thickness and function. The echocardiographic findings suggested myocardial oedema that was transient in nature. Clinical and laboratory investigation from both episodes were compatible with ISCLS. CONCLUSION: ISCLS is rare, and therefore there is only a limited understanding on the pathophysiology of this disorder. The current treatment approach is based on a few case reports and series. During the acute phase, optimal supportive management is paramount. Our case highlights the importance of early recognition and consideration for extracorporeal membrane oxygenation support in patients with a life-threatening presentation, as it was lifesaving for this child who suffered myocardial oedema and ventricular dysfunction.