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Biomedical subjects

R Asero

Publications and source records attributed to R Asero.

At least 19 recordsLinked to original sources
PubMed2001

A case of allergy to beer showing cross-reactivity between lipid transfer proteins.

BACKGROUND: Lipid transfer proteins (LTPs) are highly conserved proteins present in a broad spectrum of fruits and vegetables that might represent a novel plant panallergen. OBJECTIVE: To demonstrate that LTP is an important allergen in beer and that beer LTP cross-reacts with LTP from botanically unrelated plant-derived foods. METHODS: Serum from a patient with clinical allergy to both beer and Rosaceae was studied for IgE reactivity to LTP to several vegetable foods by RAST, ELISA, immunoblot, and inhibition studies. RESULTS: Patient's serum showed a strong IgE reactivity to LTP purified from peach peel, carrot, and broccoli, and to a 10 kD protein in both apple and peach immunoblots, whereas no reactivity to birch cross-reactive allergens such as Bet v 1, profilin, or carbohydrates was found. In inhibition studies, preabsorption of serum with apple, walnut, hazelnut, peanut, corn, and rice caused a fall of 97%, 20%, 66%, 91%, 94%, and 93%, respectively, of its reactivity to peach LTP. Beer RAST fell from 1.8 IU/mL to <0.1 IU/mL when a patient's serum was preabsorbed with recombinant carrot LTP. CONCLUSIONS: LTP is a relevant allergen in beer. Beer LTP may cross-react with LTP from several other plant-derived foods.

Adult↗
PubMed2001

Allergy to nonspecific lipid transfer proteins in Rosaceae: a comparative study of different in vivo diagnostic methods.

BACKGROUND: Lipid transfer proteins (LTPs) are the major allergens in patients sensitive to Rosaceae (apple, peach, apricot, cherry, plum, and pear) who are not allergic to birch pollen. OBJECTIVE: The purpose of this study was to find a sensitive, specific, and relatively easy method for detection of LTP-sensitive patients. METHODS: We studied 36 persons who experienced oral allergy syndrome after the ingestion of fruits in the family Rosaceae. This study cohort was divided into two groups: 18 without allergy to birch pollen (patients) and 18 with birch pollen allergy (control subjects). All were tested by skin prick tests (SPTs) with fresh Golden Delicious apple, fresh peach, and extracts of peel and pulp from both fruits. Their specific IgE reactivities against peach peel extract were further investigated by immunoblot analysis. RESULTS: All 18 subjects in the control group showed strongly positive skin reactions with both fresh apple and fresh peach, whereas no skin reactivity was found with extracts from peach peel, peach pulp, or apple pulp. Extract of apple peel produced positive skin reactions in 17 of 18 control subjects; however, the wheals were generally smaller than those induced by fresh fruits. Immunoblot analysis showed no reactivity for peach peel extract. In contrast, the SPTs with fresh fruits showed that some of the 18 patients had strongly positive reactions, but others had weak reactions or negative responses. Further, in a high proportion of the patients, consecutive SPT with fresh apple yielded inconsistent results. In all patients, SPTs with extracts from apple pulp and peach pulp were negative, whereas SPTs with peel extracts were strongly positive in all patients. In most patients, the wheal area induced by SPT with peel extracts was larger than that induced by SPTs with fresh fruits. Immunoblot analysis showed that serum specimens from all 18 patients reacted with a 10-kD protein in peach peel. This is the molecular mass of LTPs. CONCLUSIONS: In birch pollen-allergic patients, the SPTs with fresh foods still remains the most reliable method of diagnosing vegetable food hypersensitivity. In contrast, in patients not allergic to birch pollen, the most reliable strategy for detection of patients sensitive to LTPs is skin prick testing with properly prepared fruit peel extracts. The loss of Bet v 1- and Bet v 2-like structures, which probably occurs during extraction, may facilitate immediate identification of the relevant allergen.

Antigens, Plant↗
PubMed2001

Nasal polyposis: a study of its association with airborne allergen hypersensitivity.

BACKGROUND: Despite the frequent presence of clinical symptoms such as sneezing and itching, elevated histamine and IgE in extracellular polyp fluids, tissue eosinophilia, and degranulated mast cells, allergy is not considered an important cause of nasal polyposis. OBJECTIVE: To investigate the prevalence of immediate skin reactivity to airborne allergens in patients with nasal polyposis. METHODS: Sixty-eight patients with nasal polyposis and 36 controls with chronic sinusitis were submitted to skin prick tests (SPTs) with a large series of seasonal and perennial airborne allergens including: grass, mugwort, ragweed, pellitory, plantain, birch, hazel, olive, cypress, house dust mites, cat and dog dander, and thirteen molds (Alternaria, Aspergillus, Cladosporium, Penicillium, Candida, Trichophyton, Fusarium, Curvularia, Botrytis, Pullularia, Rhizopus, Mucor, Helminthosporium). RESULTS: Forty-three of 68 (63%) patients with nasal polyposis versus 6 of 35 (17%) controls were positive on SPT with airborne allergens (P < .001). A comparison with 1,128 subjects with respiratory allergy seen from 1996 to 1999 showed a markedly higher prevalence of sensitivity to Candida albicans (19 of 43 [44%] vs 8 of 1,128 [1%]; P < .001) and to house dust mites (12 of 43 [28%] vs 154 of 1,128 [14%]; P < .05) among allergic patients with polyps. Altogether, 30 of 43 (70%) patients versus 215 of 1,128 (19%) controls were sensitive to at least one perennial airborne allergen (ie, mold, mite, or animal dander) on SPT (P < .001); in contrast, 26 of 43 (60%) patients versus 942 of 1,128 (84%) controls were sensitive to seasonal airborne allergens (P < .005). A review of the clinical histories of SPT-positive patients revealed the presence of obstructive rhinitis and chronic rhinorrhea only in most cases, whereas acute symptoms, such as sneezing and itching, were reported only by a minority of subjects. CONCLUSIONS: A clinically slight respiratory allergy, particularly to perennial airborne allergens, might play a relevant role in the pathogenesis of nasal polyposis, probably through the induction of a long-lasting inflammation of the nasal mucosa.

Adolescent↗
PubMed2001

Chronic urticaria: novel clinical and serological aspects.

BACKGROUND: Recently, distinct studies have shown that: (a) chronic idiopathic urticaria (CIU) is autoimmune in 30-50% of cases; (b) in patients with CIU the autologous serum skin test is inhibited by heparin; and (c) basophil histamine release induced in vitro by CIU sera maybe complement-dependent. OBJECTIVE: To carry out a comprehensive clinical and serological study on CIU based upon these observations. METHODS: Three hundred and six adults with CIU underwent intradermal (ID) test with autologous serum; 57 of them with autologous heparinized plasma as well. Sera from 121 patients (plasmas from 17) were employed to induce in vitro histamine release from basophils of normal donors. The effects of heating (56 degrees C, 60 min), filtration through membrane, and preincubation with heparin were evaluated as well. RESULTS: Autologous serum and plasma induced a weal and flare reaction in 205 out of 306 (205/306; 67%) and in 8/57 (14%) patients, respectively. Positive plasma skin tests were observed only in patients showing strongly positive serum skin tests. Plasma did not elicit any skin reaction in 3/3 patients with dermatographism who showed a positive intradermal test with saline. Sera from 20/121 (16.5%) patients induced significant histamine release from basophils of normal donors. 19/20 sera were from patients with a positive intradermal test; thus, basophil histamine release assay was positive in 19/87 (21.8%) patients with a positive serum skin test. Heating at 56 degrees C x 1 h markedly reduced the histamine-releasing activity of both serum and plasma from in vitro reactors. Ultrafiltered fractions > 100 kDa of both sera tested retained the histamine-releasing activity, whereas fractions < 100 kDa were not able to induce any histamine release. Heparin dose-dependently inhibited histamine release induced by sera and plasma, and by basophil agonists such as anti-IgE, formyl-methionyl-leucyl-phenilalanine, and interleukin (IL)-3. CONCLUSIONS: 67% of our patients with CIU showed a positive autologous serum skin test. Sera from about 20% of those positive on autologous serum skin test induced histamine release from normal basophils in vitro probably as a consequence of the presence of functional autoantibodies. The marked difference between in vivo and in vitro findings could reflect the existence of a mast cell-specific histamine-releasing factor which does not release histamine from basophils of healthy blood donors. However, it might be also the result of in vivo priming of patients' cutaneous mast cells or of heterogeneity of basophil donors. At least in some cases complement seems essential for histamine-releasing activity of serum from patients with CIU. Heparin inhibits histamine release from both basophils (in vitro) and mast cells (in vivo), probably acting directly at a cellular level.

Adolescent↗
PubMed2000

Fennel, cucumber, and melon allergy successfully treated with pollen-specific injection immunotherapy.

BACKGROUND: In subjects with both pollinosis and vegetable food allergy, most allergenic epitopes of fruits and vegetables are present in pollen. A recent study showed a marked reduction or a total disappearance of apple-induced oral allergy syndrome in patients receiving injection immunotherapy with birch pollen extracts. OBJECTIVE: To assess whether vegetable food allergy following other kinds of primary pollinosis may be successfully treated with pollen-specific immunotherapy. METHODS: A 34-year-old woman with long-standing pollinosis and typical oral allergy syndrome (OAS) with the ingestion of both fennel and cucumber and whose OAS was associated with immediate laryngeal edema after the ingestion of melon, was treated with two commercial depot aluminum hydroxide-adsorbed extracts of 1 grass pollen and 2 mugwort pollen 50% + ragweed pollen 50%. RESULTS: After 36 months of injection specific immunotherapy, the patient was able to tolerate both fresh fennel and cucumber without consequence on open oral challenge tests. After 43 months of immunotherapy, the patient tolerated fresh melon as well on open oral challenge. She has re-introduced these vegetables in her normal diet. Skin tests showed no reactivity to fresh fennel and there was a reduction of the wheal induced by fresh cucumber. CONCLUSION: Vegetable food allergy following primary sensitization to pollens, other than birch, may also be effectively reduced by pollen-specific injection immunotherapy.

Adult↗
PubMed2000

Leukotriene receptor antagonists may prevent NSAID-induced exacerbations in patients with chronic urticaria.

BACKGROUND: About 30% of patients with chronic urticaria experience flares of hives and/or angioedema after ingesting either aspirin or nonsteroidal anti-inflammatory drugs. In such patients, cross-reactivity to all NSAIDs seems to occur suggesting a mechanism dependent on cyclooxygenase inhibition. OBJECTIVE: To evaluate the preventive effect of leukotriene receptor antagonists on urticaria exacerbations induced by NSAIDs in a patient with chronic urticaria. METHODS: A 59-year-old woman with a 2-year history of recurrent urticaria exacerbated by different NSAIDs including aspirin 500 mg (2 episodes), piroxicam 20 mg, and nimesulide 100 mg (1 episode each) was studied. Acetaminophen 375 mg and floctafenine 50 mg induced a marked flare of urticaria/angioedema in a single-blind, placebo-controlled challenge. RESULTS: The patient was totally urticaria free during a 3-week course of montelukast 10 mg once a day. After montelukast withdrawal, a gradual relapse of urticaria/angioedema occurred along with a further acute urticaria/angioedema episode after a single piroxicam, 20-mg tablet. Zafirlukast 20 mg twice daily was started. After some days the patient was urticaria-free again, and after 3 weeks she tolerated a 6-day course of injective piroxicam (20 mg once a day) without any problem. To date the patient is still urticaria-free. CONCLUSION: Leukotriene receptor antagonists may prevent the severe urticaria/angioedema exacerbations which follow the use of NSAIDs in some patients with chronic urticaria.

Angioedema↗
PubMed2000

Detection of allergens in plantain (Plantago lanceolata) pollen.

BACKGROUND: Allergens in Plantago lanceolata have not been characterized yet. The objective was to characterize some plantain-pollen allergens and to investigate the cross-reactivity between plantain and grass pollens. METHODS: Sera from four patients monosensitive to plantain pollen and from eight grass-pollen-allergic patients showing strong skin reactivity to plantain pollen in the skin prick test (SPT) underwent immunoblot analysis with both Plantago and grass mix extract. Moreover, immunoblot inhibition experiments were done with grass mix extract as inhibitor. RESULTS: All four sera from plantain-allergic patients reacted to two distinct bands at 17 and 19 kDa, and 2/4 sera showed further reactivity to a 40-kDa protein, which in one case represented the most prominent IgE-binding allergen. Plantain-monosensitive subjects did not show any reactivity to grass-pollen extract, and preabsorption of their sera with grass-pollen extract did not cause any loss of reactivity to plantain pollen. Sera from all eight grass-pollen-allergic controls reacted to a 30-kDa protein in plantain pollen, and some sera showed cross-reactivity to higher and lower molecular-weight structures as well. In all cases, plantain reactivity was totally abolished by preabsorption of sera with grass-pollen extract. A preliminary investigation by immunoblot showed that polyclonal IgG anti-Phl p 5 (but not polyclonal Phl p 1) from rabbit reacted to a 30-kDa protein in plantain pollen. CONCLUSIONS: Three specific allergens (of 17, 19, and 40 kDa, respectively) have been detected in plantain pollen. Further studies on a larger number of patients will determine whether these proteins may be considered major allergens. Cross-reactivity between grass and plantain pollen is mainly caused by a 30-kDa protein in plantain pollen. Group 5 grass-pollen allergen is probably responsible for most grass/plantain cross-reactivity.

Adult↗
PubMed2000

Lipid transfer protein: a pan-allergen in plant-derived foods that is highly resistant to pepsin digestion.

BACKGROUND: Lipid transfer proteins (LTPs) are small molecules of approximately 10 kD that demonstrate high stability. They have recently been identified as allergens in the Rosaceae subfamilies of the Prunoideae (peach, apricot, plum) and of the Pomoideae (apple). They belong to a family of structurally highly conserved proteins that are also present in non-Rosaceae vegetable foods. OBJECTIVE: The aim of this study was to investigate the cross-reactivity to non-Rosaceae LTPs, and to study the role of protein stability in allergenicity. METHODS: Thirty-eight patients with a positive SPT to Rosaceae fruit extracts enriched for LTP were characterized by interview and SPT. To investigate IgE cross-reactivity between Rosaceae and non-Rosaceae LTPs, RAST and RAST inhibition as well as ELISA and ELISA inhibition were performed, using whole food extracts and purified LTPs. Both purified natural LTPs (peach, carrot and broccoli) and Pichia pastoris recombinant LTPs (carrot and wheat) were included. Pepsin digestion was used to address the role of stability in the allergenicity of LTPs. RESULTS: IgE antibodies to Rosaceae LTPs reacted to a broad range of vegetable foods, including Gramineae (cereals), Leguminosae (peanut), Juglandaceae (walnut), Anacardiaceae (pistachio), Brassicaceae (broccoli), Umbelliferae (carrot, celery), Solanaceae (tomato), Cucurbitaceae (melon), and Actinidiaceae (kiwi). Binding and inhibition studies with purified natural and recombinant LTPs confirmed their role in this cross-reactivity. Many of these cross-reactivities were accompanied by clinical food allergy, frequently including systemic reactions. Antibody binding to LTP was shown to be resistant to pepsin treatment of whole extract or purified LTP. CONCLUSION: LTP is a pan-allergen with a degree of cross-reactivity comparable to profilin. Due to its extreme resistance to pepsin digestion, LTP is a potentially severe food allergen.

Adolescent↗
PubMed1999

Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts.

BACKGROUND: A minority of patients with oral allergy syndrome (OAS) induced by Rosaceae or nuts are positive on skin prick tests with commercial food extracts. This suggests reactivity against distinct stable allergens. OBJECTIVES: (1) To define the prevalence of subjects positive on skin prick tests with commercial extracts among patients with OAS caused by Rosaceae and/or nuts and (2) To investigate whether commercial extracts-positive subjects show some peculiar clinical feature and may represent a specific subset with food allergy. METHODS: Skin prick tests were carried out with a large panel of commercial extracts of airborne allergens (Allergopharma) and of vegetable foods (Dome/Hollister-Stier) in 298 adults with OAS caused by Rosaceae (n = 237) and or nuts (n = 161), positive on skin prick tests with fresh offending foods. RESULTS: 25/237 (11%) patients were positive on prick tests with commercial plum extract. This subgroup showed a higher incidence of systemic symptoms (64% versus 6%; P < .001) and a lower incidence of birch pollen allergy (12% versus 99%; P < .001) than commercial extract-negative patients; moreover, 36% versus 0%, respectively, did not have respiratory allergy (P < .001). Apple and peach were the main offending foods among commercial extract-negative and commercial extract-positive patients, respectively (87% versus 44% for apple, P < .001; and 52% versus 88% for peach, P < .005). Eight of one hundred sixty-one (5%) nuts-sensitive patients were positive on prick test with commercial walnut extract. This subgroup showed a higher proportion of patients who experienced systemic symptoms (63% versus 6%, P < .001), a lower prevalence of birch pollen allergy (13% versus 97%, P < .001), and a higher prevalence of grass pollen allergy (88% versus 41%, P < .05) than commercial extract-negative subjects. Further, reactivity against commercial walnut extract was associated with skin reactivity against commercial extracts of peanut (88% versus 37%, P < .005), tomato (75% versus 5%, P < .001), and plum (63% versus 8%, P < .001), and inversely related with skin reactivity against fresh apple (P < .001). In most cases, high levels of IgE specific for peach, apple, and hazelnut were associated with peanut reactivity rather than with clinical sensitivity to specific foods. In a preliminary investigation, most commercial extract-positive patients reacted against a 10-kDa protein characterized as a lipid transfer protein (LTP). CONCLUSIONS: Skin prick tests with commercial extracts of plum and walnut may be usefully employed to detect patients with OAS reacting against stable allergens. The high prevalence of systemic symptoms in these patients suggests that allergens' stability is associated with a higher resistance to the gastrointestinal environment and strongly influences the clinical expression of vegetable food allergy. At least some stable allergens, namely lipid transfer protein might be shared by botanically unrelated fruits such as nuts, peanuts, legumes, tomato, and Prunoideae.

Adult↗