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Biomedical subjects

R Asero

Publications and source records attributed to R Asero.

At least 37 records · Page 2Linked to original sources
PubMed2005

The effect of thermal processing on the IgE reactivity of the non-specific lipid transfer protein from apple, Mal d 3.

BACKGROUND: Non-specific lipid transfer proteins (LTPs) are involved in allergy to fresh and processed fruits. We have investigated the effect of thermal treatment and glycation on the physico-chemical and IgE-binding properties of the LTP from apple (Mal d 3). METHODS: Mal d 3 was purified from apple peel and the effect of heating in the absence and presence of glucose investigated by CD spectroscopy, electrospray and MALDI-TOF mass spectrometry. IgE reactivity was determined by RAST and immunoblot inhibition, SPT and basophil histamine release test. RESULTS: The identity and IgE reactivity of purified Mal d 3 was confirmed. Mild heat treatment (90 degrees C, 20 min) in the absence or presence of glucose did not alter its IgE reactivity. More severe heat treatment (100 degrees C, 2 h) induced minor changes in protein structure, but a significant decrease in IgE-binding (30-fold) and biological activity (100- to 1000-fold). Addition of glucose resulted in up to four glucose residues attached to Mal d 3 and only a 2- and 10-fold decrease of IgE-binding and biological activity, respectively. CONCLUSIONS: Only severe heat treatment caused a significant decrease in the allergenicity of Mal d 3 but glycation had a protective effect. The presence of sugars in fruits may contribute to the thermostability of the allergenic activity of LTP in heat-processed foods.

Allergens↗
PubMed2004

Assessment of histamine-releasing activity of sera from patients with chronic urticaria showing positive autologous skin test on human basophils and mast cells.

BACKGROUND: All previous studies agree that only a proportion of sera from patients with chronic urticaria (CU) positive on the autologous serum skin test (ASST) are able to induce histamine release in vitro. A non-specific release of bradykinins during clotting of blood samples has been suggested; however, ASST seems rather specific and some data point to the existence of a mast cell-specific histamine-releasing factor. OBJECTIVE: To assess whether, and to what extent, the use of both human basophils and mast cells increases the sensitivity of in vitro histamine release assays (HRAs) in ASST-positive patients with CU. METHODS: The histamine-releasing activity of sera from 93 patients with CU selected on the basis of strong skin reactivity on ASST was assessed in vitro on basophils from 1 (n=86), 2 (n=31), or 3 (n=20) normal donors, and on mast cells from 1 (n=3), 2 (n=3), or 3 (n=87) normal donors. RESULTS: Sera from 88/93 (95%) patients induced significant histamine release from mast cells or basophils on at least one HRA. 76/93 (82%), 45/90 (50%), 22/80 (28%), and 6/12 (50%) sera were able to induce significant histamine release from cells of 2/5, 3/5, 4/5 and 5/5 donors, respectively. CONCLUSION: Sera from nearly all ASST-positive patients with CU are able to induce histamine release in vitro. However, the serum from each single patient seems to show its maximal activity on autologous mast cells in vivo, and functional in vitro tests show much variability and seem less sensitive than ASST in the detection of patients with histamine-releasing factors in their blood.

Adult↗
PubMed2004

Analysis of new respiratory allergies in patients monosensitized to airborne allergens in the area north of Milan.

BACKGROUND: A recent study carried out in North of Milan, an area that was recently colonized both by birch and ragweed pollen, showed that subjects developing allergies to these "new" allergens were much older than those becoming allergic to "traditional" airborne allergens, which suggests that predisposition to develop respiratory allergies is probably allergen-specific, persists throughout life, and does not occur until the patient encounters the appropriate allergen for a sufficiently long period. OBJECTIVE: The present study aimed to test this hypothesis by following-up a large cohort of patients monosensitized to airborne allergens. METHODS: The prevalence and characteristics of new sensitizations to airborne allergens after >2 years of follow-up were retrospectively assessed in 726 patients monosensitized to grass, pellitory, mite, birch, ragweed, Alternaria, mugwort, or plantain living North of Milan. RESULTS: The overall prevalence of new sensitizations was 35% (256/726), with marked differences between the subgroups ranging from 11% in Alternaria-allergic subjects to 46% in grass-allergic subjects. Patients allergic to grass, birch, or pellitory pollen showed a significantly higher propensity to become sensitized to a second airborne allergen than subjects allergic to ragweed, Alternaria, and mite. Overall, the "new" allergens (birch and ragweed) caused 228/256 (89%) new sensitizations detected in the whole study group. Ragweed pollen induced 90% (38/42) of new sensitizations in birch pollen allergic patients, and birch pollen induced 80% (8/10) of new sensitizations in ragweed allergic patients. No difference in age at the first visit or in duration of the follow-up between patients developing and not developing new respiratory allergies was observed. CONCLUSION: This study shows that: 1) predisposition to develop respiratory allergies is allergen-specific and persists throughout life; 2) proneness to become allergic to certain airborne allergens might be associated with primary sensitization to specific airborne allergens; 3) in monosensitized adults, sensitization to another airborne allergen that has been always present in that particular geographical area is unlikely.

Adolescent↗
PubMed2004

Airborne allergy to sunflower seed.

BACKGROUND: There is increasing evidence that bird fanciers may develop airborne allergies to unusual allergens. OBJECTIVE: To detect the allergen source in a bird fancier with a history of asthma associated with bird cage cleaning activities and with contact with a Brazil parrot. METHODS: SPT with a large series of both airborne and food allergens were carried out. IgE reactivity to allergens causing wheal and flare reactions was confirmed by in-vitro investigations including ELISA/ELISA inhibition and immunoblot analysis. RESULTS: Strong skin reactivity to sunflower seed was observed. Immunoblot analysis showed IgE reactivity to low m.w. proteins, most probably 2S albumin, and ELISA inhibition studies showed the absence of cross-reactivity to mustard. CONCLUSION: Sunflower seed dust may sensitize patients via the respiratory tract. Differently from previously reported cases of sunflower seed allergy, no cross-reactivity to 2S albumin from botanically unrelated seeds was found.

Allergens↗
PubMed2004

Prevalence of allergic reactions to Hymenoptera stings in northern Italy.

The epidemiology of Hymenoptera venom allergy in Europe showed prevalence of systemic reactions of about 3%, but is scantly investigated in Italy. We studied two samples of the general and an at risk population, i.e. the foresters, in northern Italy. A standardized questionnaire dealing with allergic reactions to Hymenoptera stings was submitted to the subjects included in the study, who were factory workers in Milan and Verona and foresters in Lombardy. An overall number of 574 subjects participated to the study, 462 (299 males and 163 females, mean age 40.1 yrs, range 20-63 yrs) were factory workers and 112 (all males, mean age 38.8 yrs, range 24-59 yrs) were foresters. Among factory workers, 302 (65.4%) were stung by Hymenoptera, 49 (10.6%) had had large local reactions, and 13 (2.8%) systemic reactions. Among foresters, 76 (67.8%) were stung, 11 (9.8%) had had large local reactions, and 5 (4.5%) systemic reactions. The systemic reactions were life-threatening in 3 (0.6%) industrial workers and 2 (1.8%) foresters. The prevalence of systemic reaction of 2.8% in the general population agrees with the data reported from a number of countries with temperate climate. The prevalence of 4.5% in foresters attributed to this population a risk only slightly increased.

Adult↗
PubMed2004

Clinical features of patients showing Candida hypersensitivity: an observational study.

BACKGROUND: The significance of Candida albicans as an allergen is still unclear. This study aimed at investigating the clinical features of patients monosensitized to Candida. METHODS: Thirty-four adult patients monosensitized to the yeast Candida albicans selected from a population of >7000 subjects and referred for suspect respiratory allergy were studied. Ninety subjects monosensitized to different airborne allergens served as controls. Both patients and controls underwent a clinical examination at the ENT department to detect possible nasal polyps. RESULTS: Male and female patients were equally distributed (17/17). The mean age of the patients was 58.4 years (range 23-75 years; median 59 years) vs 29.9 years (range 9-62 years) in controls (p <0.001). At baseline examination, 15 (44%) patients vs 5/90 (6%) controls were diagnosed as having nasal polyposis (p< 0.001). Polyposis was bilateral in 13/15 (87%) patients; 3 had "massive" polyps, and 4 had a clinical history of prior surgical intervention to remove nasal polyps. Eight patients (24%) had asthma, previously diagnosed as intrinsic in six cases. No patient had a history of aspirin-induced asthma (i.e. ASA triad). After one year 1/11 (9%) patients without polyps at the baseline examination had developed bilateral nasal polyposis. CONCLUSION: Candida-hypersensitivity is uncommon, occurs in older ages, and is strongly associated with nasal polyposis.

Adolescent↗
PubMed2004

Chronic autoreactive urticaria at six years of age.

A case of chronic urticaria in a child 6 years old is described. The strong skin reactivity upon intradermal injection of autologous serum suggested an autoreactive pathogenesis; however, patient's serum was unable to induce histamine release from basophils in-vitro, indicating the presence of a histamine-releasing factor specific for mast cells, and possibly other than an anti-FcepsilonRI or anti-IgE antibody. Intradermal test with autologous serum may be useful in revealing the autoreactive nature of chronic urticaria and can avoid a frustrating search for other causes of the disease. In children presenting with chronic or recurrent urticaria the diagnostic workup should include the autologous serum skin test.

Child↗
PubMed2003

How long does the effect of birch pollen injection SIT on apple allergy last?

BACKGROUND: Recent studies showed that injection specific immunotherapy (SIT) with birch pollen extract greatly reduces or cures the associated apple allergy in a large proportion of birch pollen-allergic patients. However, the long-term efficacy of SIT for apple allergy has not been assessed. OBJECTIVE: To evaluate the duration of the effect of injection SIT with birch pollen extract on apple allergy in birch pollen-allergic patients. METHODS: Thirty birch pollen-allergic patients showing both the clinical disappearance of apple allergy and a negative SPT with fresh apple at the end of their injection SIT course were followed-up at 12-month intervals from 6 months after SIT was stopped. Apple tolerance as well as SPT was assessed on all occasions. Fifty-seven birch pollen-allergic subjects without apple allergy and not submitted to SIT regularly followed-up for the onset of oral allergy syndrome (OAS) were used as controls. RESULTS: The overall prevalence of OAS after 30 months of follow-up did not differ between patients and controls. Although most patients became re-sensitized to apple by SPT over time, >50% of them were still able to tolerate eating the fruit at the 30-month follow-up visit. CONCLUSION: Although most patients show a 'natural', gradual propensity to apple re-sensitization (a consequence of prolonged and repeated inhalation of birch pollen responsible for primary sensitization?), the clinical effects of injection SIT on food allergy seem rather long lasting.

Adolescent↗
PubMed2002

Birch and ragweed pollinosis north of Milan: a model to investigate the effects of exposure to "new" airborne allergens.

BACKGROUND: The effects of sudden and massive exposure of the general population to novel airborne allergens are not known. This study aimed to investigate the clinical effects of two "new" allergens, ragweed and birch, in an area north of Milan during the last 15 years. METHODS: We reviewed the records of 2571 monosensitized patients seen during the last 10 years in two allergy units north of Milan. Data included age at onset of allergic symptoms, and family history of allergic diseases. In this sample, 500 were allergic to grass, mite, birch, and ragweed; 293 to pellitory; 167 to mugwort; 100 to Alternaria; and 11 to plantain. RESULTS: Birch pollen-allergic patients and ragweed pollen-allergic patients showed a similar mean age at onset (35.3 years vs. 35.1 years; P = NS), but were significantly older than all other groups of patients (P < 0.001). Patients allergic to ragweed and birch pollen, 304 and 323 respectively, were >30 years at the onset of allergic symptoms. A family history of allergic disorders among first degree relatives was far less frequent among patients allergic to birch pollen (29%) or ragweed pollen (27%) than among patients sensitive to all other airborne allergens, except those allergic to mugwort pollen (P < 0.001). In both ragweed and birch groups, a positive family history was significantly more common among subjects < 30 years than in those > 30 years at onset of respiratory allergy (81/196 (41%) vs. 54/304 (18%), P < 0.001 for the ragweed group; 80/177 [45%]vs. 65/323 (20%), P < 0.001 for the birch group). CONCLUSION: Exposure of the general population of this area to two new airborne allergens resulted in the onset of respiratory allergy in many older people who lacked any relevant predisposing factor. Although we cannot exclude the possibility that those who became allergic had been exposed to birch or ragweed pollen elsewhere, a more likely explanation is a specific susceptibility that remains viable until the subject encounters the "right" allergen.

Adolescent↗
PubMed2002

Immunological cross-reactivity between lipid transfer proteins from botanically unrelated plant-derived foods: a clinical study.

BACKGROUND: Lipid transfer proteins (LTP) are highly conserved and widely distributed throughout the plant kingdom. Recent studies demonstrated immunological cross-reactivity between LTP from many botanically unrelated fruits and vegetables and concluded that LTP are pan-allergens. This study aimed to evaluate the clinical relevance of such cross-reactivity in a group of subjects monosensitized to LTP. METHODS: Twenty LTP-hypersensitive patients were selected from a population of about 600 subjects with history of Rosaceae allergy by means of: 1) negative skin prick test (SPT) with a commercial birch pollen extract; 2) positive SPT with a commercial plum extract, rich in LTP but virtually lacking both Bet v 1-like proteins and profilin; 3) in-vitro IgE reactivity to the 9-10 kDa fraction of peach peel or immunoblot with peach peel showing a single band at 10 kDa; and 4) total inhibition of reactivity to whole peach extract (containing Bet v 1-related allergen, profilin, and LTP) by purified peach LTP on enzyme-linked immunoassay (ELISA). Allergy to foods other than Rosaceae was ascertained by careful interview and analysis of medical recordings. SPT with a large series of plant-derived foods were carried out as well. The cross reactivity between LTPs from botanically unrelated plant-derived foods was assessed by ELISA inhibition tests using walnut and peanut extracts as substrate, and peach LTP as inhibitor. RESULTS: All patients reported allergic reactions after the ingestion of at least one from a large number of vegetable foods other than Rosaceae, and in several cases clinical reactions were very severe (anaphylaxis, asthma, urticaria/angioedema). Nuts and peanuts were the most frequently reported causes of allergic reactions (80% and 40% of patients, respectively). All patients showed positive SPT to several non-Rosaceae food extracts. SPT with nuts, peanut, legumes, celery, rice, and corn were positive in the majority of patients. In ELISA inhibition studies, absorption of sera with peach LTP caused complete inhibition of IgE reactivity to walnut and peanut in all cases. CONCLUSION: LTP is a clinically relevant pan-allergen. Most Rosaceae-allergic, LTP-hypersensitive patients experience adverse reactions after ingestion of botanically unrelated plant-derived foods as well. In view of the high prevalence and severity of the allergic reactions induced, hazelnut, walnut, and peanut should be regarded as potentially hazardous for these patients.

Allergens↗
PubMed2001

Multiple drug allergy syndrome: a distinct clinical entity.

Multiple drug allergy syndrome is a clinical condition characterized by a propensity to react against different, chemically unrelated antibiotic or nonantibiotic drugs. The origin of this syndrome is still elusive. This article critically examines the medical literature on multiple drug allergy syndrome, compares and discusses recent personal observations obtained in patients with intolerance to multiple antibiotic or anti-inflammatory drugs, suggests possible pathogenic mechanisms for this type of drug allergy, and reports on current personal research in this field.

Drug Hypersensitivity↗