Elena Figueredo

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.

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.

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.

Identification of Cucumisin (Cuc m 1), a subtilisin‐like endopeptidase, as the major allergen of melon fruit

Background Allergenic components in melon extracts have not been described in spite of the fact that melon (Cucumis melo) is a frequent allergy‐eliciting fruit. The aim of this study was to evaluate allergenic components in melon extract and to report the identification of cucumisin as a major melon allergen.

Successful desensitization of a fixed drug eruption caused by allopurinol

acquired sensitization and desensitization also differed between the human and the rabbit, with the rabbit requiring a shorter time to develop desensitization (14 weeks) than the human (21 weeks). This could represent a true difference. It could also have occurred because the human had less frequent mosquito bites than the rabbit and received a relatively low dose of mosquito salivary antigen (100 bites every 2 weeks in a 70 kg human vs 140 bites every week in a 2 kg rabbit). We demonstrate prospectively for the first time that regular, continuous, high-dose, natural allergen exposure eventually leads to desensitization (defined as complete loss of delayed and immediate responsiveness) and that both IgE and IgG are involved in the sensitization process. This model offers an excellent opportunity for further in-depth study of immediate and delayed hypersensitivity responses in humans. The immunologic mechanisms involved may be different in humans than in animals (at least in rabbits) in which IgG acts as a blocking antibody. We thank Dr. Reinhart Brust and Mr. Ben Yang Ding for their contributions to this work.

Clinical characteristics of melon (Cucumis melo) allergy.

Background Although melon is a frequent allergy-eliciting fruit, allergic reactions to melon have rarely been reported. Objective To evaluate and describe the clinical characteristics of melon allergy in melon-allergic patients. Materials and Methods We evaluated patients allergic to melon and a control group of patients allergic to pollen. The diagnosis of melon allergy was based on a convincing clinical history, positive skin test results (prick-by-prick test), and positive results on oral challenge tests to melon. Results A total of 161 patients were included in the study: 66 in the melon allergy group and 95 in the pollen control group. The melon allergy group included 35 female and 31 male patients with a mean age of 26.6 ± 2.7 years (range, 5-61 years). Although all patients had oral symptoms, 13 (19.7%) of the patients had extraoral symptoms and none experienced generalized urticaria or anaphylaxis. Excluding other Cucurbitaceae fruits, peach, fig, and kiwi most frequently elicited positive skin test results and symptoms. Up to 23% of melon-allergic patients had a concomitant latex sensitization. Melon allergy was especially linked to pollen allergy, since all the melon-allergic patients were also allergic to pollen. Some differential features with respect to the pollen allergy control group were a higher prevalence of asthma (odds ratio [OR], 2.13; P Ulmus (OR, 42.8) and Ambrosia (OR, 22.4). Conclusion The most important conditions linked to melon allergy are pollen allergy (100%), allergy to other nonrelated fruits, mainly peach (up to 62%), and latex sensitivity (up to 23%). Some differential features of the pollinosis in melon allergy were a higher prevalence of asthma and a higher frequency of sensitization to several weed and tree pollens.

A method for quantitation of food biologic activity : Results with peach allergen extracts

OBJECTIVE The aim of this study was to develop a quantitative skin test assay for measurement of the biologic activity of food allergen extracts, as well as to report the results obtained with a peach extract labeled in food biological units (FBUs). METHODS We prepared a biologically quantified peach extract. The biologic activity was measured in FBUs by assigning 100 FBU/ml to the biologic activity of the extract that elicited a wheal area with a geometric mean equal to that produced by the prick-prick method by using the food itself in a population of 30 patients allergic to food. We evaluated 265 patients, including 70 patients allergic to peach and 195 control subjects (100 nonatopic subjects and 95 subjects allergic to pollen). The biologically quantified peach extract was used during the study and was compared with four commercial peach extracts, which were labeled in weight per volume. RESULTS The sensitivity of the nonstandardized commercial peach extracts varied from 4.3% to 74%, with biologic activity being very low in all of them. The sensitivity of the biologically quantified peach extract was 100%, with a 100% concordance between the prick-prick and the skin prick test results. CONCLUSION These data demonstrate that if peach allergen preparations were biologically standardized in FBUs, the quality of these food extracts used for diagnosis would be improved.

Anaphylactic reaction to methotrexate

rophages, platelets, and B cells are also involved in this process. Transient, increased production of IgE could activate these cells; IgE may be part of the mechanism of the acute-phase response. This would corroborate recent results pointing to higher serum IgE levels during exacerbation of rheumatoid arthritis (12) and chrotiic obstructive pulmonary disease (13). The discovery of IgE gave an insight into the fundamental mechanism of allergy. Atopy, one of the most commoti genetically determined traits, characterized by overproduction of IgE, became well defined. The observations here briefly discussed point to still another role of IgE, a role in the acute-phase response, which should be carefully examined.

Generalized dermatitis due to pseudoephedrine

. PSEUDOEPHEDRINE is a sympathomimetic drug (SD), a widely used as a nasal decongestant that seldom causes an allergic reaction. We report a patient who complained of a generalized eczematous dermatitis after oral intake of a drug containing pseudoephedrine. A 77-year-old woman presented a generalized, itchy erythematous eruption after starting oral treatment with Clamoxyl (amoxycillin) and Rinoebastel (ebastine 10 mg plus pseudoephedrine 120 mg). The lesions cleared without further desquamation within one week of stopping this medication. The same symptoms had occurred in this patient twice previously with other drugs taken for a common cold. Skin tests with penicilloyl polylysine (PPL), minor determinant mixture (MDM), penicillin G and amoxycillin, and oral challenge with amoxycillin, were negative. Patch tests were carried out with Rinoebastel (0.1 and 1% in petrolatum (pet.)) and elicited a negative reaction at 48 and 96 h. A single-blind, placebo-controlled oral challenge with Rinoebastel was also performed. Within five hours, the patient developed an itchy erythematous generalized micropapular rash, which disappeared after treatment. Oral administration of ebastine produced no reaction. A posterior oral challenge with pseudoephedrine hydrochloride (60 mg) was also followed by similar lesions. Two months later the patient agreed to be patch tested again with pseudoephedrine (10% pet. and aqueous solution (aq.)), phenylephrine (10% pet. and aq.), epinephrine (1 : 1000), terbutaline (1% aq.) and albuterol (0.5% aq.). These tests revealed a positive reaction (++), in both petrolatum and aqueous solution, to pseudoephedrine, ephedrine, and phenylephrine at day 2, persisting to day 4. The remaining tests were negative. Ten healthy controls did not react to the same patch tests. Subsequent separated challenges were carried out with epinephrine 1 : 1000 (0.3 ml), terbutaline (2.5 mg), albuterol (2 mg), ephedrine (40 mg) and phenylephrine (20 mg). All were negative, except for ephedrine, which provoked the same symptoms. Despite extensive oral use of pseudoephedrine, allergic reactions seem to be unusual3/4a nonpigmenting fixed drug eruption being the most common cutaneous reaction (1,2). Also reported have been eczematous dermatitis (3,4), an unspecified rash with joint swelling (5), scarlatiniform eruptions (6), a recurrent toxic shock syndrome (7) and a vacuolar interface dermatitis (4). In order to verify the cause of a suspected drug eruption, a challenge test is usually required. Patch tests are not usually a reliable diagnostic method; a literature search revealed only four cases of positive patch tests to pseudoephedrine (1,3,4). Positive results have been obtained at 1% concentration and with the use of petrolatum as a vehicle. However, in our patient, the patch tests were positive for both types of vehicles, but only when a higher concentration (10%) was used. Cross-sensitivity among SDs has been rarely reported. We have found crossreactivity between pseudoephedrine and ephedrine, which have a closely related chemical structure derived from the phenylpropanolamine skeleton. On the contrary, no cross-reaction has been observed in provocation tests with other SDs (phenylephrine, epinephrine/ adrenaline) which are phenylethanolamine-derived. Although our patient’s patch test with phenylephrine was positive, she tolerated it well. Thus (with the exception of ephedrine) all SDs should not be routinely prohibited in cases of sensitization to pseudoephedrine. In summary, the challenge and patch-testing results suggest a delayed hypersensitivity mechanism to pseudoephedrine in our patient’s dermatitis. In our study, pseudoephedrine 10% was a suitable concentration with which to perform the patch test.

Clinical characteristics of melon (Cucumis melo) allergy

BACKGROUND Although melon is a frequent allergy-eliciting fruit, allergic reactions to melon have rarely been reported. OBJECTIVE To evaluate and describe the clinical characteristics of melon allergy in melon-allergic patients. MATERIALS AND METHODS We evaluated patients allergic to melon and a control group of patients allergic to pollen. The diagnosis of melon allergy was based on a convincing clinical history, positive skin test results (prick-by-prick test), and positive results on oral challenge tests to melon. RESULTS A total of 161 patients were included in the study: 66 in the melon allergy group and 95 in the pollen control group. The melon allergy group included 35 female and 31 male patients with a mean age of 26.6 +/- 2.7 years (range, 5-61 years). Although all patients had oral symptoms, 13 (19.7%) of the patients had extraoral symptoms and none experienced generalized urticaria or anaphylaxis. Excluding other Cucurbitaceae fruits, peach, fig, and kiwi most frequently elicited positive skin test results and symptoms. Up to 23% of melon-allergic patients had a concomitant latex sensitization. Melon allergy was especially linked to pollen allergy, since all the melon-allergic patients were also allergic to pollen. Some differential features with respect to the pollen allergy control group were a higher prevalence of asthma (odds ratio [OR], 2.13; P < 0.05) and a statistical increase in the frequency of sensitization to several tree and weed pollens, including Ulmus (OR, 42.8) and Ambrosia (OR, 22.4). CONCLUSION The most important conditions linked to melon allergy are pollen allergy (100%), allergy to other nonrelated fruits, mainly peach (up to 62%), and latex sensitivity (up to 23%). Some differential features of the pollinosis in melon allergy were a higher prevalence of asthma and a higher frequency of sensitization to several weed and tree pollens.