Identification of gibberellin-regulated protein as a new allergen in orange allergy.

BACKGROUND: To date, three orange allergens have been reported. However, it is still unclear whether gibberellin-regulated proteins (GRPs), identified as new allergens in other fruit allergies, are also involved in orange allergy. OBJECTIVE: To investigate the allergenicity of orange GRP and to determine the clinical characteristics of patients with orange allergy who are sensitized to orange GRP. METHODS: We enrolled 14 patients (four men, 10 women, mean age: 29.6 years) who were diagnosed with orange allergy based on relevant clinical history, positive skin test, and/or positive challenge test. Orange GRP (molecular weight: 6941.6 Da) was purified by ion-exchange column chromatography. To test for orange GRP-specific IgE, we performed ELISA, basophil activation tests, and skin prick tests. Cross-reactivity of orange GRP with native peach allergen nPru p 7 and Japanese apricot nPru m 7 was analysed by ELISA inhibition assays. IgE specific for orange, grapefruit, and peach allergens rPru p 1, rPru p 3, and rPru p 4 was measured using ImmunoCAP. RESULTS: Twelve of the 14 patients (85.7%) were positive for orange GRP allergy in at least one test: 71.4% (10/14) were positive by ELISA, 50% (3/6) were positive in the basophil activation test, and 100% (4/4) were positive in the skin prick test. ELISA inhibition assays revealed cross-reactivity of orange GRP with both nPru p 7 and nPru m 7. The patients showed variable positivity for specific IgE against orange, grapefruit, rPru p 1, rPru p 3, and rPru p 4 (57.1%, 71.4%, 7.1%, 0%, and 21.4%, respectively). The most frequent symptoms of orange GRP allergy were facial swelling and oropharyngeal symptoms. CONCLUSIONS AND CLINICAL RELEVANCE: Orange GRP may be involved in orange allergy and may be a cross-reactive allergen between citrus fruits and the Rosaceae family of fruits.

Surfing as a risk factor for sensitization to poly(γ-glutamic acid) in fermented soybeans, natto, allergy.

BACKGROUND: Poly(γ-glutamic acid) (PGA) is an allergen in natto, fermented soybeans, which causes late-onset anaphylaxis. We hypothesized that jellyfish stings sensitize adults to PGA because a surfer had allergies to both natto and jellyfish, whose sting contains PGA. The aim of the study was to identify behavioral factors, such as marine sports, associated with PGA sensitization. METHODS: Outpatients diagnosed with food allergies based on relevant clinical history, positive skin test and/or food challenge test answered a questionnaire during a regular visit in 2016. RESULTS: Questionnaire data from 140 outpatients were analyzed. These patients were divided into two groups: natto allergy group (13 patients, M:F = 10:3, mean age 40.6 years) and non-natto allergy group (127 patients, M:F = 46:81, mean age 44.5 years). All patients with natto allergy had positive results in skin prick test and basophil activation test with PGA. Of these, 92.3% had a marine sport hobby, especially surfing (84.6%). PGA sensitization was independently associated with marine sports (odds ratio, 278.0, 95 percent confidence interval, 36.9-6315.9, p < 0.001) adjusted for male sex and sea bathing, but not with male sex or sea bathing. In addition, although there was no significant difference in the experience of marine sports between natto and non-natto allergy groups, the natto allergy group participated significantly more frequently in marine sports than the non-natto allergy group (p < 0.001). There was no significant difference between natto consumption amount and PGA sensitization. CONCLUSIONS: Surfing is a risk factor for PGA sensitization in those with allergy to natto.

Gibberellin-regulated protein in Japanese apricot is an allergen cross-reactive to Pru p 7.

BACKGROUND: Gibberellin-regulated protein (GRP, also known as peamaclein) was recently identified as a new marker allergen related to systemic reactions in peach allergy; however, its role in other fruit allergies is unknown. OBJECTIVE: To investigate the allergenicity of Japanese apricot (JA) GRP and clarify the clinical characteristics of JA allergy patients with GRP sensitization. METHODS: Seven patients (two males, five females, mean age 28.0 years) diagnosed with JA allergy based on relevant clinical history, positive skin test and/or challenge test were enrolled. JA GRP with a molecular weight of 6896.5 Da was purified by ion-exchange column chromatography. We performed enzyme-linked immunosorbent assay (ELISA), IgE-immunoblotting, basophil activating tests (BATs), and skin prick tests (SPTs) with purified JA GRP. To investigate the cross-reactivity between JA GRP and native Pru p 7 (nPru p 7), we performed ELISA inhibition tests. We measured specific IgE levels against apricot, peach, rPru p 1, rPru p 3, and rPru p 4 using ImmunoCAP. RESULTS: ELISA and IgE-immunoblotting using JA GRP showed positive reactions in six (85.7%) and seven (100%) patients, respectively. Five patients who provided informed consent for BATs and SPTs using JA GRP had positive results. In four patients who underwent ELISA inhibition tests using JA GRP and nPru p 7, IgE binding to one GRP inhibited binding to the other. The positivity for specific IgE against apricot, peach, rPru p 1, rPru p 3, and rPru p 4 was 14.3%, 57.1%, 0%, 0%, and 0%, respectively. Patients developed allergic reactions that were frequently accompanied with facial swelling, especially of the eyelids, which was dependent on cofactors, such as exercise. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicated that GRP might be a causative allergen of JA allergy, whose onset frequently requires a cofactor, such as exercise, and might be cross-reactive between JAs and peaches.

High prevalence of sensitization to gibberellin-regulated protein (peamaclein) in fruit allergies with negative immunoglobulin E reactivity to Bet v 1 homologs and profilin: Clinical pattern, causative fruits and cofactor effect of gibberellin-regulated protein allergy.

Gibberellin-regulated protein (GRP) is a new allergen in peach allergy, with an amino acid sequence very well conserved through several botanical species. We investigated the allergenicity of GRP in fruit allergies other than peaches and identified the clinical characteristics of fruit allergy patients with GRP sensitization. One hundred consecutive Japanese patients with fruit allergies were enrolled in the present study. To identify the features of GRP sensitization, we selected patients with negative ImmunoCAP results for Bet v 1 homologs and profilin, which are marker allergens for pollen-food allergy syndrome (PFAS), or lipid transfer protein. These patients underwent specific immunoglobulin E measurements by enzyme-linked immunosorbent assay (ELISA) and skin prick tests (SPT) using purified nPru p 7. Twenty of 100 consecutive patients with fruit allergies had negative ImmunoCAP results for Bet v 1 homologs and profilin. Thirteen (65.0%) of the 20 patients had positive ELISA and/or SPT results using nPru p 7, whereas one of the 20 patients had positive ImmunoCAP results for Pru p 3. In 13 nPru p 7-sensitized patients, the causative foods were peaches (92.3%), apricots (61.5%), oranges (46.2%) and apples (30.8%). Ten patients (76.9%) had multiple causative fruits. Frequent symptoms included facial edema (92.3%) and laryngeal tightness (66.7%). In eight patients (61.5%), exercise or aspirin intake enhanced the allergic reaction onset as cofactors. The prevalence of GRP sensitization was high in Japanese fruit allergy patients except for PFAS patients. In conclusion, GRP-sensitized patients may have allergies to multiple fruits and may show peculiar characteristics such as facial swelling and cofactor dependence.

Eyelid edema as a predictive factor for sensitization to Pru p 7 in peach allergy.

The clinical and laboratory factors related to Pru p 7 sensitization in peach allergy, compared with those associated with sensitization to Pru p 1, which is related to pollen-food allergy syndrome (PFAS), have still not been clarified. The aim of the present study was to identify the clinical and laboratory features associated with sensitization to Pru p 7. Fifty patients (male : female, 14:36; mean age, 31.8 years) with peach allergy were enrolled in this study. Specific immunoglobulin E (sIgE) against the purified nPru p 7 was measured by enzyme-linked immunoassay, whereas using ImmunoCAP, sIgE levels against peach, rPru p 1, rPru p 3 and rPru p 4 were measured. Correlations between the clinical characteristics of peach allergy and sensitization to the allergens were statistically analyzed. In 50 patients with peach allergy, 13 and 33 patients were sensitized with nPru p 7 and rPru p 1, respectively. Laryngeal tightness, conjunctival injection, facial edema, eyelid edema and urticaria were significantly associated with Pru p 7 sensitization. In contrast, oropharyngeal symptoms were strongly related to Pru p 1 sensitization but were significantly less common in the Pru p 7-positive group. Co-sensitization to the representative pollens related to PFAS, such as alder pollens, was significantly related to Pru p 1 sensitization, but not Pru p 7 sensitization. Along with the absence of co-sensitization to pollens related to PFAS, facial edema and especially eyelid edema after the ingestion of peaches could be a predictive factor for sensitization to Pru p 7.