Pawankar R, et al. Asia Pac Allergy. 2020 Jan;10(1):e11. https://doi.org/10.5415/apallergy.2020.10.e11

In September 2015, Japan experienced an unusual increase in acute asthma hospitalizations of children that coincided with an enterovirus D68 (EV-D68) epidemic. The objective of this study is to investigate whether EV-D68 had a causal relationship with the spike in asthma hospitalizations. A nation-wide retrospective survey of asthma hospitalizations of children was performed for the period from January 2010 through October 2015. The Japanese Society of Pediatric Allergy and Clinical Immunology asked its affiliated hospitals to report monthly numbers of hospitalizations, ICU admissions and mechanical ventilations due to acute asthma exacerbation. The data were retrieved from medical databases using predefined search criteria: diagnosis of asthma or asthmatic bronchitis, admission, and age <20 years. Monthly numbers of EV-D68 detection were also obtained from the Infectious Disease Surveillance Center of Japan. A Granger causality test was used to analyze the association of EV-D68 detections for asthma exacerbation. A total of 157 hospitals reported 87,189 asthma hospitalizations, including 477 ICU admissions and 1193 mechanical ventilations, during the survey period of 5 years and 10 months. The numbers of these events increased drastically in September 2015. The Granger causality test verified the association between EV-D68 and asthma hospitalizations/mechanical ventilations. The most-affected age group was 3-6 years old. The spike in pediatric asthma hospitalizations in Japan in September 2015 was found to be associated with the EV-D68 epidemic. Respiratory pathogens can cause "epidemics" of asthma exacerbation. Coordinated surveillance of infectious diseases and asthma may be beneficial for prevention and better control of both illnesses.

Food allergy occurs due to IgE- and mast cell–dependent intestinal inflammation. Previously, we showed that histamine-releasing factor (HRF), a multifunctional protein secreted during allergy, interacts with a subset of IgE molecules and that the HRF dimer activates mast cells in an HRF-reactive IgE-dependent manner. In this study, we investigated whether HRF plays any role in food allergy. Specifically, we determined that prophylactic and therapeutic administration of HRF inhibitors that block HRF-IgE interactions reduces the incidence of diarrhea and mastocytosis in a murine model of food allergy. Food allergy–associated intestinal inflammation was accompanied by increased secretion of the HRF dimer into the intestine in response to proinflammatory, Th2, and epithelial-derived cytokines and HRF-reactive IgE levels at the elicitation phase. Consistent with these data, patients with egg allergy had higher blood levels of HRF-reactive IgE compared with individuals that were not hypersensitive. Successful oral immunotherapy in egg-allergy patients and food-allergic mice reduced HRF-reactive IgE levels, thereby suggesting a pathological role for HRF in food allergy. Together, these results suggest that antigen and HRF dimer amplify intestinal inflammation by synergistically activating mast cells and indicate that HRF has potential as a therapeutic target in food allergy.

Influenza vaccines produced in embryonated eggs might pose a risk to patients with egg allergy. However, patients experiencing influenza vaccine-associated anaphylaxis (IVA) do not always have egg allergy. In the 2011-2012 season, an unusually high incidence of IVA was reported in Japan. We sought to identify the cause of the increase in anaphylactic events in 2011-2012 in Japan. We collected blood specimens from patients with IVA from all areas of Japan. We analyzed 19 patients with confirmed IVA and 25 age-matched control subjects, including 10 with egg allergy who had no adverse events after corresponding vaccination. ELISA was used to measure specific IgE levels to the trivalent vaccines of several manufacturers and hemagglutinin proteins derived from both egg and cell cultures. Antigen-induced basophil activation was evaluated by measuring CD203c expression by means of flow cytometry. Vaccine excipients were also examined for effects on CD203c expression. None of the patients with IVA had severe egg allergy. Levels of specific IgE antibodies to influenza vaccine antigens, whole-vaccine products from different manufacturers, and hemagglutinin proteins (A H1, H3, and B) derived from both egg and cell cultures were significantly increased in patients with IVA compared with those in control subjects. Influenza vaccine-induced CD203c expression in basophils was also highly enhanced in patients with IVA but not in control subjects. Because IVA was most frequent in patients who received 2-phenoxyethanol (2-PE)-containing vaccine, the effect of this preservative on basophil activation was examined, and the activation was slightly enhanced by 2-PE but not thimerosal. The 2011-2012 IVA spike in Japan was caused by specific IgE antibodies to influenza vaccine components. Excipients could not be implicated, except for a modest effect of 2-PE.