Kayoko Matsunaga

BACKGROUND: Despite the increasing prevalence of walnut allergy (WA), no allergen components have been established as markers of disease severity. This study aimed to identify proteins specifically associated with severe WA in children. METHODS: We analyzed 48 children aged 3.4-16 years who underwent an oral food challenge to walnut between February 2019 and March 2022. Children with positive and negative reactions were categorized into a WA group and walnut sensitization (WS) group, respectively. The dose-adjusted reaction severity of WA patients was quantified using the Anaphylaxis Scoring Aichi's total score divided by the cumulative protein dose that induced symptoms (TS/Pro). Using the median TS/Pro value in all cases of the WA group as a cut-off, 11 of 21 WA patients with stored sera were classified as high TS/Pro (TS/Pro ≥154.1); the remaining 10 patients were classified as low TS/Pro. Immunoblotting, mass spectrometry, and enzyme-linked immunosorbent assay (ELISA) were used to identify candidate markers of WA severity. RESULTS: Jug r 1-specific IgE (sIgE) levels were higher in the WA group, but were not significantly associated with TS/Pro. Immunoblotting and mass spectrometry detected phospholipase D alpha 1 (PLDa1) in 5/11 (45.5%) high TS/Pro patients and 1/10 (10%) low TS/Pro patients (p = .149). ELISA with recombinant PLDa1 confirmed similar results. Moreover, the absorbance of recombinant PLDa1-sIgE was significantly correlated with TS/Pro (ρ = 0.47, p = .032). CONCLUSIONS: PLDa1 (Jug r 9) is a candidate marker of WA severity. The early identification of children at risk of severe WA may aid clinicians in optimizing their management strategies.

BACKGROUND: The relationship between the severity of peanut allergy and component-specific immunoglobulin E (IgE) remains partially analyzed. We aimed to explore this relationship using a proteomic analysis of pediatric patients with peanut allergy. METHODS: Immunoblotting and mass spectrometry were used to identify candidate peanut allergen components, which were confirmed via enzyme-linked immunosorbent assay using sera from pediatric patients with peanut allergy confirmed through a positive oral food challenge test (OFC). The association between each protein-specific IgE level and the severity of peanut allergy was compared. The severity of peanut allergy was quantified as TS/Pro, which is the total score (TS) of Anaphylaxis Scoring Aichi divided by the cumulative protein dose of peanuts at the OFC (Pro). RESULTS: This study comprised 52 patients with peanut allergy. In addition to the known peanut allergen components, we discovered seven allergens in more than five participants. Among the participants, 24 (46.2%) had Annexin Gh1-specific IgE. Ara h 2 (rs = 0.67, p < .001) and Ara h 6 (rs = 0.66, p < .001) specific IgEs and the sum of the absorbance of all seven candidates (rs = 0.64, p < .001) were strongly correlated with TS/Pro. Ara h 1 (rs = 0.30, p < .05), Ara h 3 (rs = 0.37, p < .01), Ara h 7 (rs = 0.34, p < .05), and the seed biotin-containing protein SBP65 (rs = 0.35, p < .05) specific IgEs were correlated with TS/Pro. CONCLUSION: Ara h 2- and 6-specific IgEs and sensitization diversity were the most significant factors that correlated with peanut allergy severity. We identified SBP65 (Ara h 20) as a potential novel allergen component related to peanut allergy severity.

Patients with peach allergy who experience severe symptoms, including anaphylaxis, reportedly have a higher positivity for peach gibberellin-regulated protein (GRP)-specific immunoglobulin (Ig) E than those with only oral symptoms. However, a study in Italy investigating apple allergy (another Rosaceae fruit) found no clear association between apple GRP-specific IgE levels and clinical disease types. This study aimed to evaluate the clinical utility of GRP-specific IgE measurement in Japanese patients with apple allergy. We collected sera from apple-allergic patients in Japan and measured their IgE levels specific to apple GRP. Apple-allergic patients (14 with oral reactions and 14 with systemic reactions) and seven non-allergic controls were examined. The specific IgE levels against apple, Mal d 1, Mal d 4, Japanese cedar, Japanese alder, Japanese white birch, Bet v 1, and Bet v 2 were also determined using 3gAllergy™. Positive results for apple-GRP-specific IgE by enzyme-linked immunosorbent assay were obtained in one patient with oral reactions and in seven cases of systemic reactions. Exercise as a cofactor was involved in cases with high apple GRP-specific IgE. GRP expression was considerably lower in apples than in peaches, as detected by reverse transcription-quantitative polymerase chain reaction testing. Thus, GRP-specific IgE may be an important marker for diagnosing systemic reactions triggered by exercise in fruits with low GRP expression, such as apples.