Javier Cuesta-Herranz

Peanut allergy: Clinical and immunologic differences among patients from 3 different geographic regions

BACKGROUND Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens. OBJECTIVE We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach. METHODS Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed. RESULTS American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age. CONCLUSIONS Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.

Monoclonal antibody–standardized cat extract immunotherapy: Risk-benefit effects from a double-blind placebo study

Twenty-eight patients (14 in an active treatment group and 14 in a placebo group) with rhinoconjunctivitis and asthma caused by cat hypersensitivity took part in a placebo-controlled, randomized, double-blind study to evaluate the risk-benefit quotient of the maintenance dose corresponding to 13.2 micrograms Fel d I antigen. The cat extract was biologically standardized and quantified with monoclonal antibodies (100 biological units: 33 microgram of Fel d I antigen, 650 micrograms of albumin, and 99 micrograms of Fel d Bd/K30 antigen). After 1 year of treatment, the systemic reactions to cat extract immunotherapy were mild and infrequent. Improvement was observed in the active treatment group in comparison with the placebo group in the medication-symptoms score (p < 0.001); in skin prick test (p < 0.001), conjunctival provocation test (p < 0.001), and allergen bronchoprovocation test (p < 0.05) results, and in nonspecific bronchial hyperreactivity measured with methacholine, which was not statistically significant. This study demonstrates the favorable risk-benefit quotient of the dose of 13.2 micrograms of Fel d I antigen, which may serve as a future reference in defining the optimum dose and appropriate proportion of antigens that should be administered in cat extract immunotherapy.

Allergy to plant-derived fresh foods in a birch- and ragweed-free area.

Allergy to plant‐derived fresh foods has often been reported in geographical areas where birch or ragweed pollens are frequent and has been attributed to cross‐reactivity to pollens.

Differences among Pollen-Allergic Patients with and without Plant Food Allergy

Background: A considerable number of pollen-allergic patients develops allergy to plant foods, which has been attributed to cross-reactivity between food and pollen allergens. The aim of this study was to analyze the differences among pollen-allergic patients with and without plant food allergy. Methods: Eight hundred and six patients were recruited from 8 different hospitals. Each clinical research group included 100 patients (50 plant food-allergic patients and 50 pollen-allergic patients). Diagnosis of pollen allergy was based on typical case history of pollen allergy and positive skin prick tests. Diagnosis of plant-food allergy was based on clear history of plant-food allergy, skin prick tests and/or plant-food challenge tests. A panel of 28 purified allergens from pollens and/or plant foods was used to quantify specific IgE (ADVIA-Centaur® platform). Results: Six hundred and sixty eight patients (83%) of the 806 evaluated had pollen allergy: 396 patients with pollen allergy alone and 272 patients with associated food and pollen allergies. A comparison of both groups showed a statistically significant increase in the food and pollen allergy subgroup in frequency of: (1) asthma (47 vs. 59%; p < 0.001); (2) positive skin test results to several pollens: Plantago,Platanus,Artemisia,Betula,Parietaria and Salsola (p < 0.001); (3) sensitization to purified allergens: Pru p 3, profilin, Pla a 1 – Pla a 2, Sal k 1, PR-10 proteins and Len c 1. Conclusion: Results showed relevant and significant differences between both groups of pollen-allergic patients depending on whether or not they suffered from plant-derived food allergy.

Characterization of peach thaumatin‐like proteins and their identification as major peach allergens

Background Peach is the most important fruit related to food allergy in the Mediterranean area. Pru p 3, its lipid transfer protein, has been described as the principal allergen responsible for cross‐reactivities with other foods and pollen and the severity of clinical symptoms. However, the involvement of other allergenic families cannot be ruled out. Thaumatin‐like proteins (TLPs) have been described as food allergen in several fruits, such as apple, cherry, kiwi and banana, and pollen.

Identification of major allergens in watermelon.

Background: Watermelon is a worldwide consumed Cucurbitaceae fruit that can elicit allergic reactions. However, the major allergens of watermelon are not known. The aim of this study is to identify and characterize major allergens in watermelon. Methods: Twenty-three patients allergic to watermelon took part in the study. The diagnosis was based on a history of symptoms and positive skin prick-prick tests to watermelon, confirmed by positive open oral challenge testing to watermelon pulp. Allergenic components were detected by SDS-PAGE and immunoblotting. Molecular characterization of IgE-binding bands was performed by N-terminal amino acid sequencing and mass spectrometry. Allergens were purified combining several chromatographic steps. Results: Several IgE binding bands (8–120 kDa) were detected in watermelon extract. Three major allergens were identified as malate dehydrogenase (36 kDa), triose phosphate isomerase (28 kDa) and profilin (13 kDa). Purified allergens individually inhibited IgE binding to the whole watermelon extract. Conclusions: All in all these results indicate that malate dehydrogenase, triose phosphate isomerase and profilin are major allergens involved in watermelon allergy.

Pru p 3 (LTP) content in peach extracts

Background: Lipid transfer proteins are molecules widely distributed in fruits. Sensitization to LTP is frequent in fruit sensitive patients. The aims of this study were to purify LTP and to assess the content of LTP in ripe peach peel and pulp extracts by ELISA inhibition using polyclonal antibodies.

Isolation and identification of an 11S globulin as a new major allergen in mustard seeds

BACKGROUND Although mustard seed allergy has been largely reported during the preceding 20 years, currently only 2 allergens, Sin a 1 and Bra j 1, have been identified. OBJECTIVE To improve the characterization of the allergenic profile of yellow mustard seeds by reporting the identification and biochemical characterization of an 11S globulin as a new major allergen. METHODS Mustard seed proteins were separated using size exclusion and ion-exchange chromatographic columns, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 2-dimensional polyacrylamide gel electrophoresis. Separation of different polypeptide chains was achieved by reverse-phase high-performance liquid chromatography. Mass spectrometry after tryptic digestion and Edman degradation were used to determine amino acid sequences of peptides. IgE binding assays were performed with 13 serum samples from mustard allergic patients in immunoblotting and enzyme-linked immunosorbent inhibition assays. RESULTS A protein of 51 kDa was recognized as a major allergen by patients allergic to mustard and called Sin a 2. The allergen was dissociated in 2 chains of 36 and 23 kDa, which also bound IgE. N-terminal end and internal amino acid sequences allowed identification of the new allergen as a seed storage 11S globulin belonging to the Cupin super family. Purified allergen was able to inhibit the IgE binding of sera from allergic patients to mustard seeds extract in up to 55% of the responses. CONCLUSIONS An 11S globulin storage protein has been isolated and identified as a novel major allergen of mustard seeds.

The Involvement of Thaumatin-Like Proteins in Plant Food Cross-Reactivity: A Multicenter Study Using a Specific Protein Microarray

Cross-reactivity of plant foods is an important phenomenon in allergy, with geographical variations with respect to the number and prevalence of the allergens involved in this process, whose complexity requires detailed studies. We have addressed the role of thaumatin-like proteins (TLPs) in cross-reactivity between fruit and pollen allergies. A representative panel of 16 purified TLPs was printed onto an allergen microarray. The proteins selected belonged to the sources most frequently associated with peach allergy in representative regions of Spain. Sera from two groups of well characterized patients, one with allergy to Rosaceae fruit (FAG) and another against pollens but tolerant to food-plant allergens (PAG), were obtained from seven geographical areas with different environmental pollen profiles. Cross-reactivity between members of this family was demonstrated by inhibition assays. Only 6 out of 16 purified TLPs showed noticeable allergenic activity in the studied populations. Pru p 2.0201, the peach TLP (41%), chestnut TLP (24%) and plane pollen TLP (22%) proved to be allergens of probable relevance to fruit allergy, being mainly associated with pollen sensitization, and strongly linked to specific geographical areas such as Barcelona, Bilbao, the Canary Islands and Madrid. The patients exhibited >50% positive response to Pru p 2.0201 and to chestnut TLP in these specific areas. Therefore, their recognition patterns were associated with the geographical area, suggesting a role for pollen in the sensitization of these allergens. Finally, the co-sensitizations of patients considering pairs of TLP allergens were analyzed by using the co-sensitization graph associated with an allergen microarray immunoassay. Our data indicate that TLPs are significant allergens in plant food allergy and should be considered when diagnosing and treating pollen-food allergy.

Pollen allergy in peach-allergic patients : Sensitization and cross-reactivity to taxonomically unrelated pollens

BACKGROUND Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization. OBJECTIVE The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them. METHODS One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin. RESULTS The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients. CONCLUSION The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.