An unusual cause of food-induced anaphylaxis in mothers

Safety of the extension of use of galacto-oligosaccharides (GOS) as a novel food in food for special medical purposes pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the extension of use of galacto-oligosaccharides (GOS) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF (β-GOS) is produced from milk lactose using a β-galactosidase derived from Bifidobacterium bifidum and it is proposed to be used in food for special medical purposes (FSMP). The target population is the general population from 4 years of age onwards. GOS produced according to the same production process are already authorised and included in the EU Union list of novel foods. The applicant stated that the maximum daily intake from the use in FSMP is 8.25 g GOS. GOS are already authorised for use in food supplements up to a daily dose of 16.2 g. FSMP containing GOS are not intended to be used if food supplements containing GOS are consumed on the same day. The information provided on the proposed use levels and anticipated intake does not raise safety concerns. The Panel concludes that the proposed extension of use of GOS in FSMP is safe under the proposed conditions of use.

An Evaluation of the Mechanisms of Galacto-Oligosaccharide (GOS)-Induced IgE Cross-Linking on Basophils in GOS Allergy

The prebiotics, galacto-oligosaccharides (GOS), are small carbohydrate molecules with 1–7 galactose units linked to glucose and have been shown to trigger IgE-mediated anaphylaxis in some cases following ingestion. It is still an unresolved question of how GOS cross-links IgE on basophils. In this study, we examined whether human galectins, a class of lectins that bind specifically to β-galactoside carbohydrates, are involved in GOS-induced basophil activation. Basophil activation test to GOS and control allergen, Blomia tropicalis (Blo t) extract were performed in the presence or absence of four sugar-based galectin inhibitors (lactose, thiodigalactoside [TDG], TD139, and GB1107) and one peptide-based inhibitor, G3-C12. Results showed that TD139, GB1107, and G3-C12 did not display a specific inhibitory effect on GOS-induced basophil activation as compared to control allergen. An inhibitory effect of lactose and TDG on GOS-induced basophil activation was observed and varied between subjects with up to 100% inhibition at low doses of GOS. The results of competitive ELISA suggest that the inhibitory effects of high dose lactose and TDG on the basophil activation is likely due to the cross-reactivity of GOS-specific IgE to lactose and TDG. Basophil activation is performed using purified basophils suggested that cell surface receptors on other blood cells were not required to induce basophil activation. In conclusion, our results suggest that GOS, a low molecular weight sugar, is able to cross-link IgE independently.

State-of-the-Art on Biomarkers for Anaphylaxis in Obstetrics

Anaphylaxis is an unpredictable systemic hypersensitivity reaction and constitutes a high risk of maternal and fetal morbidity and mortality when occurring during pregnancy. Currently, the acute management of anaphylaxis is based on clinical parameters. A total serum tryptase is only used to support an accurate diagnosis. There is a need to detect other biomarkers to further assess high-risk patients in obstetrics. Our objective is to present biomarkers in this complex interdisciplinary approach beyond obstetrician and anaesthetic management. Candidate biomarkers derive either from mediators involved in immunopathogenesis or upcoming molecules from systems biology and proteomics. Serum tryptase is determined by singleplex immunoassay method and is important in the evaluation of anaphylactic mast cell degranulation but also in the assessment of other risk factors for anaphylaxis such as systemic mastocytosis. Another category of biomarkers investigates the IgE-mediated sensitization to triggers potentially involved in the etiology of anaphylaxis in pregnant women, using singleplex or multiplex immunoassays. These in vitro tests with natural extracts from foods, venoms, latex or drugs, as well as with molecular allergen components, are useful because in vivo allergy tests cannot be performed on pregnant women in such a major medical emergency due to their additional potential risk of anaphylaxis.

Modular synthesis and immunological evaluation of suspected allergenic galactooligosaccharides

Galactooligosaccharides (GOS) are widely used in the food industry as prebiotics and in very rare cases, can lead to an allergic reaction. Due to the microheterogeneity of GOS it is very difficult to extract pure and well defined oligosaccharides to establish which component is responsible for the observed allergenicity. Herein, we report the chemical synthesis of a suspected allergen 4PX and three closely related oligosaccharides based on a modular approach. The fact that synthesized 4PX and a regioisomer did not cause basophil activation in subjects with confirmed GOS-allergy excludes both tetrasaccharides as key-epitopes in GOS-allergenicity in Singapore.

Shellfish/crustacean oral allergy syndrome among national service pre-enlistees in Singapore

Background

All Singaporean males undergo medical screening prior to compulsory military service. A history of possible food allergy may require referral to a specialist Allergy clinic to ensure that special dietary needs can be taken into account during field training and deployment.

Objective

To study the pattern of food allergy among pre-enlistees who were referred to a specialist allergy clinic to work up suspected food allergy.

Methods

Retrospective study of all pre-enlistees registered in the Clinical Immunology/Allergy New Case Registry referred to the Allergy Clinic from 1 August 2015 to 31 May 2016 for suspected food allergy.

Results

One hundred twenty pre-enlistees reporting food allergy symptoms other than rash alone were referred to the Allergy Clinic during the study period. Of these, 77 (64.2%) had food allergy. Among those with food allergy, mean age was 19.1 ± 1.5 years. They comprised predominantly Chinese (66.2%) and Malays (20.8%). The most commonly reported foods were shellfish/crustaceans (78%), peanut (15.6%), and egg (6.5%). Self-limiting oral allergy syndrome, OAS (itchy lips and throat with/without lip angioedema) was the most common manifestation (n = 33, 42.9%) followed by anaphylaxis (n = 23, 29.9%). Majority of OAS was from shellfish/crustacean (90.6%); of which shrimp (30.3%), crab (15.2%), and lobster (3.0%) were the most common. Mild childhood asthma (69.7%), allergic rhinitis (6.3%), and eczema (6.1%) were the most common atopic conditions among individuals with shellfish/crustacean OAS. This pattern was similar for shellfish/crustacean anaphylaxis. Skin prick tests were most commonly positive for shrimp (OAS 87.1% vs. anaphylaxis 100%), crab (OAS 95.8% vs. 90.9%), and lobster (OAS 91.7% vs. 63.6%).

Conclusion

OAS to shellfish/crustaceans was more common than anaphylaxis among this study population of young males referred for food allergy symptoms other than rash alone.