岡本 薫

BACKGROUND: Buckwheat allergy carries a high risk of anaphylaxis. Although the oral food challenge (OFC) is the diagnostic gold standard, it can provoke severe reactions, leading many patients to adopt elimination diets. Conventional markers, including buckwheat-specific IgE (Bw-sIgE) and skin prick testing, have limited accuracy. The IgE crosslinking-induced luciferase expression (EXiLE) assay is a serum-based in vitro cell-activation test that has shown high accuracy for other food allergies. We evaluated its utility for buckwheat allergy. METHODS: This multicenter observational study in Japan enrolled participants with buckwheat-specific IgE ≥ 0.35 UA/mL (n = 25), categorized as buckwheat allergy (BwA) or non-buckwheat allergy (non-BwA) based on OFC results. The EXiLE assay used crude buckwheat antigen at 0.1-1000 ng/mL. Diagnostic performance was compared using receiver operating characteristic (ROC) curves for EXiLE, Bw-sIgE, and the Bw-sIgE/total IgE ratio. RESULTS: Among 25 participants, the EXiLE assay demonstrated superior diagnostic performance compared to Bw-sIgE and the Bw-sIgE/total IgE ratio. The area under the ROC curve (AUC) was 0.96 at 10 ng/mL (1 ng/mL, 0.94), exceeding Bw-sIgE (0.68) and the Bw-sIgE/total IgE ratio (0.72). At optimal cutoffs, EXiLE achieved sensitivity 0.92, specificity 0.92, and LR+ 11.1 (versus LR+ 3.2 for Bw-sIgE and 2.5 for the IgE ratio), indicating fewer false positives and better overall accuracy. CONCLUSION: The EXiLE assay provides high diagnostic accuracy for IgE-mediated buckwheat allergy and, as a serum-based in vitro assay, may reduce reliance on OFC and help avoid unnecessary elimination diets.

Abstract Eczema herpeticum (EH) is a disseminated cutaneous infection with herpes simplex virus (HSV) that develops in patients with atopic dermatitis. The kinetics and clinical significance of HSV viremia in EH are poorly understood. Herein, we report HSV DNAemia in a child with EH 12 months after the completion of chemotherapy for Hodgkin lymphoma.

Objectives: Fish roe is a common allergen in Japan. We have previously reported that although immunoglobulin (IgE) from patients with salmon roe (SR) or pollock roe (PR) allergies cross-react, 70% of patients with SR allergy can consume PR without developing any symptoms. However, a correlation between clinical cross-reactivity and serological cross-reactivity remains to be demonstrated. Methods: Serum samples were collected from 15 patients with SR allergy who had consumed cooked PR previously. Among these volunteers, four had experienced immediate symptoms after consuming cooked PR, while the others had exhibited no symptoms of PR allergy. A competitive enzyme-linked immunosorbent assay (ELISA) was performed to analyze the serological cross-reactivity with SR and PR. Immunoblotting inhibition assays were performed using serum samples that had been pre-incubated with SR or PR extracts. Results: In ELISAs, binding to SR was inhibited by >50% when the serum samples from patients with both SR and PR allergies were pre-incubated with PR extract (p=0.0256). In immunoblots, pre-incubation of serum samples with PR extract inhibited detection of the 16-kDa protein, which likely corresponds to the major SR allergen beta' component, significantly more for samples from patients with both SR and PR allergies (100%) than for samples from those with only an SR allergy (18.2%) (p=0.011). Conclusions: The superior competitive binding of the sera from patients with both SR and PR allergies to PR compared with that to SR may induce clinical cross-reactivity between SR and PR.