Editor’s comment: MUC5AC and MUC5B are the major secreted polymeric mucins in airways, but in asthmatic patients, their pathophysiological relevance remains unclear. In this cross-sectional study of patients with steroid-untreated mild asthma and healthy controls, Tajiri et al. showed that sputum MUC5AC and MUC5B levels were significantly higher in patients with asthma than in controls. In addition, they showed that sputum MUC5AC levels positively correlated with FeNO, sputum eosinophil proportion, and airway sensitivity, suggesting the involvement of MUC5AC in type 2/eosinophilic airway inflammation.

Editor’s comment: Although oral food challenge tests (OFCs) are the gold standard for food allergy diagnosis, little is known about the optimal interval between antigen ingestion. In this study, Kitamura et al. evaluated the total symptom score, total ingested dose, and the proportions of severe reactions and adrenaline use. They did a retrospective chart review of 945 OFCs, eliciting objective reactions to wheat, egg, and milk. They showed that a 60-minute interval is safer than a 30- or 40-minute interval for OFCs in patients with a low threshold dose for food allergy.

Editor’s comment: Serological testing is important in diagnosing food allergy to avoid risks such as anaphylaxis from oral food challenge tests. With respect to tree nuts, singleplex tests for allergen components showed diagnostic utility for cashew/pistachio, hazelnut, and walnut allergies. In this study, Akarsu et al. investigated the utility of multiplex tests (i.e., ALEX2) in diagnosing tree nut allergy in 169 children. They showed that a multiplex component-based allergen macroarray test is as reliable and useful as a singleplex assay for predicting tree nut-allergies in children.