Kayoko Matsunaga

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.