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Biomedical subjects

V Pravettoni

Publications and source records attributed to V Pravettoni.

At least 37 records · Page 2Linked to original sources
PubMed1998

Atopy and intolerance of antimicrobial drugs increase the risk of reactions to acetaminophen and nimesulide in patients allergic to nonsteroidal anti-inflammatory drugs.

This study evaluated the risk factors for developing allergic reactions to alternative drugs such as acetaminophen and nimesulide in 367 patients intolerant of nonsteroidal anti-inflammatory drugs (NSAID) compared to 243 healthy controls. All subjects were given test doses (TD) of acetaminophen and nimesulide, and age, sex, atopy, and history of reactions also to unrelated drugs were compared in those who reacted and those who were tolerant of the challenge. TD was positive in 49 of 367 (14%) NSAID-allergic patients and in one (0.4%) of the controls (P<0.001). No difference was found in age and sex between the TD-positive and TD-negative subjects, although a significantly larger number of females were NSAID allergic (P<0.01). Of the 367 patients, 208 had a history of reactions only to NSAID, and 148 to NSAID and antimicrobial drugs (AMD). TD with acetaminophen or nimesulide was positive in 6% of patients intolerant only of NSAID and in 24% of those intolerant of both NSAID and AMD, with an odds ratio of 4.82. Atopy was more frequent among patients (36%) than controls (23%) (P=0.004), among TD-positive (51%) than TD-negative patients (33.5%) (P<0.02), and among patients intolerant of NSAID and AMD (48%) than those intolerant only of NSAID (P=0.006). The odds ratios were, respectively, 1.87, 2.57, and 3.16. This study provides evidence that atopy and history of allergic reactions to AMD increase the likelihood of intolerance of usually well-tolerated alternative drugs such as acetaminophen and nimesulide in subjects allergic to NSAID.

Acetaminophen↗
PubMed1996

Identification of the allergenic components of kiwi fruit and evaluation of their cross-reactivity with timothy and birch pollens.

BACKGROUND: Only a few food allergens have as yet been identified, mainly because of the difficulty of obtaining a sufficient number of patients who are clinically sensitized to a given food. This is more feasible in the case of the oral allergy syndrome (OAS), a common form of food allergy, which is especially prevalent in patients with pollinosis. OBJECTIVE: We designed a study to identify the allergens of kiwi fruit (Actinidia chinensis) by analyzing the sera of patients with OAS for kiwi and to examine the cross-reactivity of these allergens with timothy and birch pollen allergens. METHODS: Twenty-seven patients with OAS for kiwi, a positive skin prick test response and serum IgE antibody to kiwi, and a positive open kiwi challenge test result and three patients who had OAS with severe systemic symptoms, which excluded a challenge test, were included in this study. The different polypeptide components of an extract of fresh kiwi were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis and analyzed by IgE immunoblotting with sera from these patients. Cross-reactivity with the two pollen extracts was assessed by inhibition of the immunoblots with pooled and individual patients' sera. RESULTS: Twelve IgE-binding components with molecular weights ranging from 12 to 64 kd were identified in the kiwi extract, but only a 30 kd component acted as major allergen, being recognized by sera of 100% of these patients. Inhibition of kiwi immunoblots with timothy and birch pollen extracts demonstrated strong cross-reactivity with some of the kiwi allergens, suggesting complete identity between certain food and pollen allergens; whereas others, particularly the 30 kd allergen, were only partially inhibited, suggesting much weaker cross-reactivity. CONCLUSIONS: Kiwi fruit contains a large number of allergens widely cross-reacting with allergens in grass and birch pollen extracts. Nevertheless, the major allergen at 30 kd appears to be specific for kiwi.

Allergens↗
PubMed1994

Allergenic cross-reactivity among peach, apricot, plum, and cherry in patients with oral allergy syndrome: an in vivo and in vitro study.

BACKGROUND: Oral allergy syndrome in response to fruits and vegetables frequently occurs as clusters of hypersensitivity to members of the same botanical family, for which the immunologic basis lies in a number of common allergens, most of them still unidentified. OBJECTIVE: This study was designed to assess the in vivo and in vitro cross-reactivity between fruits of the Prunoideae subfamily (i.e., peach, cherry, apricot, and plum) and to identify their major allergens and the cross-reactivity of the peach extract with grass and birch pollen. METHODS: The in vivo study was conducted by skin prick tests and open food challenges with fresh fruits in 23 patients with oral allergy syndrome for peach and positive skin prick test and RAST results for the other Prunoideae. In vitro sodium dodecylsulfate-polyacrylamide gel electrophoresis was followed by immunoblotting and immunoblotting-inhibition. RESULTS: A 13 kd component was identified as the only major allergen common to all the Prunoideae, the other major allergens were found at 14 kd in peach and at 30 kd in cherry. Immunoblotting inhibition showed wide cross-reactivity within the Prunoideae, whereas grass and birch pollen partially inhibited the peach blotting. CONCLUSIONS: Clinical cross-reactivity to Prunoideae is essentially due to a common 13 kd IgE-binding component, which seems to be the most important major allergen of this subfamily, not shared with grass and birch pollen.

Allergens↗
PubMed1994

A double-blind, placebo-controlled study of immunotherapy with an alginate-conjugated extract of Parietaria judaica in patients with Parietaria hay fever.

A double-blind, placebo-controlled study was conducted to evaluate the efficacy and safety of immunotherapy (IT) with a partially purified alginate-conjugated extract of Parietaria judaica (Conjuvac Parietaria, Dome/Hollister-Stier) in patients suffering from rhinoconjunctivitis caused by Parietaria pollen. Eighteen patients (10 women, 8 men, mean age 35 years) received active treatment and 17 (10 women, 7 men, mean age 42.5 years) received placebo. Actively treated patients had significantly lower nasal symptom/medication scores (running nose P = 0.0087 and sneezing P = 0.048) during the Parietaria pollen season. Significant decreases in specific skin (P < 0.01), nasal (P < 0.05), and conjunctival (P < 0.01) reactivity to the Parietaria extract and significant increases of specific IgG (P < 0.001), IgG1 (P < 0.001), and IgG4 (P < 0.001) in actively treated patients, but not in placebo, were found. IT was well tolerated, the active extract inducing five mild systemic reactions (four rhinitis and one urticaria) and placebo two (rhinitis). A significant correlation was found between low skin reactivity and high specific IgG (P = 0.0002) and IgG4 (P = 0.036). These findings indicate that IT with a partially purified P. judaica extract is an effective and safe treatment for Parietaria pollen allergy. The correlation between low immediate skin reactivity and high specific IgG and IgG4 suggests that, at least in the studied cutaneous model, these antibodies may exert a blocking effect.

Adjuvants, Immunologic↗
PubMed1993

IgE-mediated allergy from vegetable allergens.

Allergy to fresh fruits and vegetables is IgE-mediated. Its main clinical features are local, such as oral pruritus and swelling of lips and tongue but systemic symptoms such as urticaria, asthma, or anaphylactic shock may occur. Clinical associations with allergic rhinitis due to cross-reactive antigens of pollens and foods are frequent.

Adolescent↗
PubMed1992

Clinical evaluation of CAP System and RAST in the measurement of specific IgE.

We investigated the diagnostic value of a new in vitro test, Pharmacia CAP System (Pharmacia Diagnostics AB, Uppsala, Sweden), for the quantitative measurement of allergen-specific IgE antibodies by comparison with RAST in 2 groups of patients, 71 atopic and 48 non-atopic. In the last 20 years RAST has supplied a good diagnostic tool, but this test presents some problems, the main one being sensitivity. The new test has a solid phase able to bind even very small amounts of specific IgE and an anti-IgE tracer with very low cross-reactivity with other immunoglobulins, thus presenting more favourable conditions. From the analysis of our results, Pharmacia CAP System gave higher sensitivity (94% compared to 88% of RAST) with no loss of specificity (96% for both tests). The reliability of these results is ensured by the proper selection of patients who were all suffering from pollinosis and were clinically diagnosed as certainly hypersensitive to a single pollen. A positive trend was found between severity of asthma and levels of specific IgE for timothy. Pharmacia CAP System appears to identify a larger number of atopic patients than RAST.

Adolescent↗
PubMed1992

Clinical and immunological effects of immunotherapy with alum-absorbed grass allergoid in grass-pollen-induced hay fever.

A double-blind, placebo-controlled study of immunotherapy was conducted in 19 patients with grass-pollen hay fever to evaluate the efficacy and safety of a formalinized depot grass allergoid. The patients were assessed before and during IT by clinical (symptom-medication scores during the grass- pollen season, specific nasal and skin reactivity) and immunological (specific IgE, IgG, IgG1 and IgG4 antibodies) parameters. High doses of grass allergoid, corresponding to a cumulative pre-seasonal dosage of 46,050 PNU, were administered, with only one systemic reaction. The actively treated patients had significantly lower symptom-medication scores than placebo (p less than 0.01) during the month of May and showed a significant decrease in specific skin (p less than 0.01) and nasal (p less than 0.05) reactivity, and a significant early increase in specific IgE (p less than 0.01), IgG (p less than 0.0005), IgG1 (p less than 0.001) and IgG4 (p less than 0.05), with a subsequent decrease of IgE and IgG1. No differences were detected in any of these parameters in the placebo group. A correlation was found between high IgG4/IgG1 ratio and the specific skin reactivity decrease (r = 0.691, p less than 0.05), whereas a high IgG4/IgG1 ratio was associated with higher symptom-medication scores (r = 0.654, p less than 0.05). Possible explanations of these apparent discrepancies are proposed.

Adolescent↗
PubMed1990

A double-blind study of hyposensitization with an alginate-conjugated extract of Dermatophagoides pteronyssinus (Conjuvac) in patients with perennial rhinitis. II. Immunological aspects.

In a 2-year double-blind placebo controlled study an immunological evaluation was carried out on 33 patients (15 males, 18 females, mean age 29.2 years) with mite-induced perennial rhinitis who were submitted to specific immunotherapy (IT) with an alginate-conjugated extract of D. pteronyssinus. The behaviour of IgE, IgG, IgG1 and IgG4 antibodies specific to D. pteronyssinus and its major allergen Der p1 was characterized by assessment of their changes in serum, and changes in IgG in nasal secretions during the treatment. The placebo-treated patients did not show any significant variation in the levels of specific antibodies, while in the actively treated patients we found: a statistically significant decrease (P less than 0.005) of specific IgE, a statistically significant increase of specific IgG (P less than 0.005), IgG1 (P less than 0.005) and IgG4 (P less than 0.005) in serum and a statistically significant increase (P less than 0.001) of specific IgG in nasal secretions. The IgG response showed an early relative predominance of the IgG1 subclass and a late absolute predominance of IgG4 subclass, that confirmed the model of IgG4 restriction in prolonged allergen stimulation. No correlation was found between immunological and clinical data.

Adjuvants, Immunologic↗
PubMed1989

Role of the elimination diet in adults with food allergy.

The aim of the study was to check whether, after a period of complete exclusion of the offending foods in adult subjects suffering from food allergy, these foods could subsequently be safely reintroduced into the diet. Patients with chronic urticaria and/or perennial rhinitis negative for secondary pathology or other allergies were subjected to a strict diagnostic protocol for food allergy. Briefly, out of a case list of 207 patients, we found 23 patients whose symptoms were clearly related, on open reintroduction, to at least one food. The really offending foods in these patients were subsequently identified by double-blind, placebo-controlled food challenges. Only 10 of the 23 patients had positive challenges for 13 foods. Double-blind challenges were repeated after 1 year or more of avoidance of the offending foods to evaluate the persistence or disappearance of sensitivity. We found that five (38%) of the 13 previously offending foods were well tolerated. Thus, in adults, as previously proved in children, dietary avoidance of the offending foods appears to be an effective measure for dealing with food allergy. The kind of foods involved and the completeness of their avoidance appeared to be important factors favoring the reestablishment of tolerance in adults.

Adolescent↗
PubMed1988

Clinical reliability of diagnostic tests in allergic rhinoconjunctivitis.

To determine the diagnostic value and precision of the quantitative skin test (QST), RAST, specific nasal (NPT) and conjunctival (CPT) provocation tests, we studied 91 patients, suffering from allergic rhinoconjunctivitis with positive skin prick tests (SPT) to common allergens, among whom sixty-nine of them had symptoms related to the positive SPT, and 22 had no clinical correspondence. In these two groups, by comparing the threshold of positivity, we investigated whether there was any parallelism between responses to the tests considered. We also compared the level of specific IgE (RAST) to the wheal-areas evoked by preliminary SPT for the corresponding allergen in order to detect any quantitative relationship between these investigations. Increasing concentrations of standardized allergen extracts (from 10 to 100,000 BU/ml) were used in all in vivo tests. NPT was evaluated on the basis of multiple recordings of nasal resistances by anterior passive rhinomanometry. QST proved to correlate well with RAST and its easier method ensures it a major role in assessing the levels of allergic sensitization. SPT wheal-areas and RAST vales correlated well only for grass and birch, presumably because of better standardization of these allergen extracts. When provocation tests, especially NPT, were positive, patients were almost always symptomatic for the allergen tested (high positive predictive value). Likewise, 21 out of the 22 asymptomatic subjects had negative NPT (high specificity). These results suggested the utility of standardized provocation tests in order to restrict diagnosis to the truly causative allergens in patients with multiple positive SPT results.

Adolescent↗
PubMed1987

IgE-mediated food allergy.

The behaviour of some immunologic parameters was studied in order to explain the presence or the lack of symptomatology in subjects with IgE specific to foods. In particular, we compared the levels of serum and salivary IgA and IgE antibody specific to apple in 33 patients allergic to birch and with anti-apple IgE, of whom 24 had oral allergy syndrome after eating apple and nine were apple tolerants. We found no differences in the IgE-related parameters such as levels of anti-apple IgE antibody in serum and secretions, mean size of apple skin prick test, and number of patients with a positive histamine release from peripheral basophils stimulated by apple. Similarly, we detected no statistically significant differences in serum and salivary total IgG and total anti-apple IgA antibody of the two groups. We could, however, observe a significantly higher anti-apple salivary IgA/anti-apple serum IgE and anti-apple salivary IgA/anti-apple serum IgA ratios and a significant correlation between the same parameters in tolerant patients when compared with the intolerants. These results seem to suggest that the presence of appropriate levels of secretory anti-apple IgA associated to anti-apple IgE might be one of the factors playing a key role in the prevention of clinical symptoms in atopic subjects.

Food Hypersensitivity↗
PubMed1987

Antihistaminic treatment of allergic rhinitis: a double-blind study with terfenadine versus dexchlorpheniramine.

A double-blind study was carried out in 65 patients with seasonal rhinitis to compare the effectiveness and tolerance of terfenadine and dexchlorpheniramine. Patients were allocated at random to receive treatment for 1 week with either 60 mg terfenadine twice daily or 2 mg dexchlorpheniramine maleate 3-times daily. Before and after treatment, patients underwent RAST and skin prick tests for reactivity to pollen and those who were positive also had rhinomanometric measurements made of nasal resistance. Diary cards were used by patients to record the severity of nasal obstruction, rhinorrhoea, sneezing, watery, irritated and red eyes, itching of the nose, throat and eyes, and cough. Details were also kept of the frequency and severity of any side-effects. Pollen counts were taken daily during the treatment period. The results showed that both terfenadine and dexchlorpheniramine produced good or excellent relief of the main symptoms in 78% and 73% of the patients, respectively. There was no significant correlation between the pollen count and reduced symptom severity. Both drugs produced a reduction in total nasal resistance but this was not significantly different from initial values, neither was there a significant difference between treatment. Terfenadine was well tolerated and side-effects incidence was significantly lower (p less than 0.01) than in patients treated with dexchlorpheniramine, particularly so with reference to drowsiness.

Adolescent↗