Real-World Sensitization and Tolerance Pattern to Seafood in Fish-Allergic Individuals

BACKGROUND

Seafood is a common cause of food allergy and anaphylaxis, but there are limited published real-world data describing the clinical presentation of fish and shellfish allergies.

OBJECTIVE

This study aimed to examine the clinical characteristics, immunological profile, and tolerance pattern to fish, crustaceans, and mollusks in fish-allergic individuals.

METHODS

Patients presenting with IgE-mediated fish allergy between 2016 and 2021 were recruited. A comprehensive sensitization profile including specific IgE and skin prick test to various fish and shellfish species and a detailed clinical history including individuals' recent seafood consumption were evaluated.

RESULTS

A total of 249 fish-allergic individuals (aged 4.2 ± 5.8 years) were recruited from 6 allergy clinics in Hong Kong, and they had experienced their fish-allergic reaction 2.2 ± 3.4 years before enrollment. Seventy-five subjects (30%) reacted to either grass carp, salmon, grouper, or cod in oral food challenges. We identified an IgE sensitization gradient that corresponded to the level of β-parvalbumin in fish. In total, 40% of fish-allergic individuals reported tolerance to 1 or more types of fish, more commonly to fish with a lower β-parvalbumin level such as tuna and salmon, compared with β-parvalbumin-rich fish such as catfish and grass carp. Despite fish and shellfish cosensitization, 41% of individuals reported tolerance to crustaceans, mollusks, or both, whereas shellfish avoidance occurred in half of the fish-allergic individuals, of whom 33% lacked shellfish sensitization.

CONCLUSIONS

Fish allergy commonly presents in early childhood. A considerable proportion of fish-allergic patients are selectively tolerant to certain fish, typically those with lower levels of β-parvalbumin. There is an unmet need to promote precision medicine for seafood allergies.

Differential patterns of fish sensitization in Asian populations: Implication for precision diagnosis

BACKGROUND

The current diagnostics of fish allergy lack sufficient accuracy such that more reliable tests such as component-resolved diagnosis (CRD) are urgently needed. This study aimed at identifying fish allergens of salmon and grass carp and evaluating the sensitization pattern in fish allergic subjects from two distinct populations in Asia.

METHODS

One hundred and three fish allergic subjects were recruited from Hong Kong (67 subjects) and Japan (46 subjects). Western blot and mass spectrometry were used to identify allergens from salmon and grass carp. Fish allergens were purified and tested against 96 sera on ELISA to analyze patients' sensitization pattern. The protein profiles of salmon meat prepared under different cooking methods until core temperature reached 80 °C were evaluated by SDS-PAGE and mass spectrometry.

RESULTS

Three common allergens between salmon and grass carp, namely enolase, glycerldehyde-3-phosphate dehydrogenase (GAPDH) and parvalbumin, and two salmon-specific allergens collagen and aldolase were identified. Parvalbumin was the major allergen for both fishes showing an overall sensitization rate of 74.7%, followed by collagen (38.9%), aldolase (38.5%) and enolase (17.8%). Japanese subjects showed more diverse allergen sensitization pattern and more frequent IgE-binding to heat-labile salmon allergens. Compared with steaming and boiling, cooking by baking and frying retained more fish proteins inclusive of heat-labile allergens.

CONCLUSIONS

Fish allergic patients from different Asian populations show varying fish allergen sensitization profiles. The relevant extracts and components for diagnosis are population-dependent but parvalbumin and collagen are important biomarkers. Cooking methods modify allergen composition of salmon and appear to influence patients' allergic manifestations.

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.

Cell-Based Functional IgE Assays Are Superior to Conventional Allergy Tests for Shrimp Allergy Diagnosis

BACKGROUND

The diagnosis of shellfish allergy currently relies on patient history, skin prick test (SPT), and serum specific IgE (sIgE) quantification. These methods lack sufficient diagnostic accuracy, whereas the gold standard of oral food challenges is risky and burdensome. Markers of reactivity and severity of allergic reactions to shellfish will improve clinical care of these patients.

OBJECTIVES

This study compared the diagnostic performance of SPT, sIgE, basophil activation test (BAT), and IgE crosslinking-induced luciferase expression (EXiLE) test for shrimp allergy.

METHODS

Thirty-five subjects with documented history of shrimp allergic reactions were recruited and grouped according to results of double-blind, placebo-controlled food challenge (DBPCFC). In addition to routine diagnostics, BAT (Flow CAST) and EXiLE test with shrimp extract and tropomyosin were performed.

RESULTS

Of 35 subjects, 15 were shrimp allergic with pruritus, urticaria, and itchy mouth on DBPCFC, whereas 20 were tolerant to shrimp. Tropomyosin only accounted for 53.3% of sensitization among subjects with challenge-proven shrimp allergy. BAT using shrimp extract as stimulant showed the highest area under curve value (0.88), Youden Index (0.81), likelihood ratio (14.73), odds ratio (104), and variable importance (4.27) when compared with other assays and tropomyosin diagnosis. Results of BAT significantly correlated with those of EXiLE (r = 0.664, P < .0001).

CONCLUSIONS

BAT is a more accurate diagnostic marker for shrimp allergy than SPT and shrimp sIgE, whereas the EXiLE test based on an IgE crosslinking assay is a good alternative to BAT. Tropomyosin may not be the most important shrimp allergen in Chinese, which warrants further investigation to search for other major allergens and diagnostic markers.

Determinants for asthma control, quality of life and use of complementary and alternative medicine in asthmatic pediatric patients in four cities

BACKGROUND

Asthma is a significant chronic health problem worldwide. Management aims at disease control by reducing functional impairment and exacerbations and improving quality of life (QoL). We report a multi-center study to survey asthma control and QoL in four cities in the Pearl River Delta.

METHODS

The conjoint survey involved ten Hong Kong pediatric hospitals/units, two Shenzhen hospitals, two Macau hospitals, and two Guangzhou hospitals on asthma control (using Asthma Control Test) and QoL (Pediatric Allergic Disease Quality of Life Questionnaire, PADQLQ). Acceptability of a treatment is graded as very good/good/fair/poor.

RESULTS

Good asthma control was only reported in 80% subjects in Hong Kong, but higher in sister cities (85-94%, P < 0.001). Allergic rhinitis, "incense burning", and "smoker in family" were prevalent among the four cities. Logistic regression showed better control of asthma was associated with better PADQLQ (B = - 0.029, P < 0.001), better acceptability of bronchodilator (B = - 1.488, P = 0.025), negatively with "smoker in family" (B = - 0.83, P = 0.015) and various PADQLQ domains. Conversely, worse PADQLQ was associated with allergic rhinitis severity (B = 4.77, P < 0.001), poor control of asthma (B = 7.56, P < 0.001), increased frequency of traditional Chinese medicine use (B = 1.7, P < 0.05), increased frequency of bronchodilator usage (B = 1.05, P < 0.05), "smoker in family" (B = 4.05, P < 0.05), and incense burning at home (B = 3.9, P < 0.05).

CONCLUSIONS

There are some clinical and cultural differences among the four southern Chinese cities within the Guangdong province. This study identifies potentially modifiable environmental and treatment factors associated with poor asthma control and QoL for health-care interventions. Having a smoker in the family is independently associated with poor asthma control and QoL.

Hypersensitivity to antipyretics: pathogenesis, diagnosis, and management

Antipyretics are commonly prescribed drugs and hypersensitivity occurs at rates of 0.01% to 0.3%. Hypersensitivity can be due to immune mechanisms that include type I to IV hypersensitivity. Type I hypersensitivity results from specific immunoglobulin E production following sensitisation on first exposure. Subsequent exposures elicit degranulation of mast cells, culminating an immediate reaction. Non-type I hypersensitivity is a delayed reaction that involves various effector cells, resulting in maculopapular rash, fixed drug eruptions, drug reaction with eosinophilia and systemic symptoms, and Stevens-Johnson syndrome/toxic epidermal necrolysis. Antipyretics also cause non-immune hypersensitivity via cyclooxygenase inhibition. Apart from hypersensitivity to parent compounds, hypersensitivity to excipient has been reported. Clinical manifestations of antipyretic hypersensitivity involve the skin, mucosa, or multiple organs. Diagnosis of hypersensitivity requires a detailed history taking and knowledge of any underlying disorders. Differential diagnoses include infection, inflammatory conditions, and antipyretics acting as co-factors of other allergens. Investigations include specific immunoglobulin E assays, lymphocyte transformation test, basophil activation test, and skin prick test. Lack of standardisation and a scarcity of available commercial reagents, however, limit the utility of these tests. A drug provocation test under close supervision remains the gold standard of diagnosis. A trial of the culprit drug or other structurally different antipyretics can be considered. Patients with confirmed hypersensitivity to antipyretics should consider either avoidance or desensitisation. Other theoretical options include subthreshold or low-dose paracetamol, cyclooxygenase-2 inhibitors, pre-medication with antihistamines with or without a leukotriene receptor antagonist, co-administration of prostaglandin E2 analogue, traditional Chinese medicine, or desensitisation if antipyretics are deemed desirable. Safety and efficacy of unconventional treatments warrant future studies.

Fractional exhaled nitric oxide-guided algorithm for children with asthma

Fractional exhaled nitric oxide (FeNO) is a surrogate marker of eosinophilic airway inflammation in asthma. The randomized controlled parallel study published by Peirsman et al combined GINA guidelines and FeNO level in guiding drug treatment in children with mild to severe asthma. Their target was to control the FeNO level below 20 ppb. The FeNO group resulted in increasing the dosage of inhaled corticosteroid and the usage of leukotriene receptor antagonist. However, the study was not truly randomized and drug adherence was not reported. The FeNO-guided algorithm failed to improve the primary outcome, the symptom-free days, but did result in decreasing the number of acute exacerbations and unscheduled contacts. Unfortunately the authors did not demonstrate a persistent and significant difference in FeNO levels between both groups. As the final FeNO levels were not reported, it remains unclear whether their target was met.

Evaluation of sleep disturbances in children with epilepsy: a questionnaire-based case-control study

Epilepsy is a chronic neurological disorder accompanied by a wide range of comorbid conditions that can adversely affect the quality of life of children. Sleep disturbances not only predispose children to mood, cognitive, and behavioral impairments, but also have a significant impact on physical health. The aim of this study was to evaluate sleep patterns among Chinese children with epilepsy and healthy subjects in Hong Kong, and examine the relationship between parent-reported sleep problems and specific epilepsy parameters. We conducted a cross-sectional, questionnaire-based, case-control study and included 63 children with epilepsy and 169 healthy children aged between 4 and 12 years. The Children's Sleep Habits Questionnaire (CSHQ) was used as an assessment tool. Our results indicated that children with epilepsy have similar sleep patterns but greater sleep disturbances compared with healthy subjects. Sleep problems should not be overlooked, and a comprehensive review of the sleep habits of this group of patients should be conducted.