Identification of a polygalacturonase (Cup s 2) as the major CCD-bearing allergen in Cupressus sempervirens pollen.

As IgE glyco-epitopes, also referred to as cross-reactive carbohydrate determinants (CCDs), can share significant structural homologies between different plants, they are prone to extensive cross-reactivity among allergen pollen extracts. Here, cypress pollen allergens, especially a polygalacturonase (PG), were further characterized using double one-dimensional electrophoresis (D1-DE). The presence of specific IgE directed against CCDs was investigated by bromelain IgE inhibition and concanavalin A binding assays using sera of cypress pollen-sensitized patients. Our results showed that IgE reactivity to CCDs in Cupressus sempervirens pollen extracts is mainly related to bromelain-type epitopes of a newly identified cypress PG. This glycoprotein has been further characterized through an immunoproteomic approach and officially indexed as Cup s 2 by the WHO/IUIS allergen nomenclature. Cup s 2 could thus be associated with the increased prevalence of IgE reactivity to cypress pollen extracts because of CCD interference.

Asthma among workers in healthcare settings: role of disinfection with quaternary ammonium compounds.

INTRODUCTION: An increased incidence of asthma has been reported among healthcare workers. The role of quaternary ammonium compounds (QACs), commonly used in cleaning/disinfection products, has not been clearly defined. The aim of this study was to analyse associations between asthma and occupational exposure to disinfectants, especially QACs. METHODS: The study was performed on a stratified random sample of the various healthcare departments of 7 healthcare settings. The study included: questionnaire, physical examination and specific IgE assays. Occupational exposure assessment was performed by means of a work questionnaire, workplace studies and a review of products ingredients. Data were analysed by logistic regression. RESULTS: Response rate was 77%; 543 workers (89% female) participated; 37.1% were registered nurses (RNs), 16.4% auxiliary nurses (ANs), 17.3% cleaners; 32.8% were atopic. 335 participants were exposed to QACs. Nursing professionals reported a significantly higher risk of reported physician-diagnosed asthma and, for RNs, of nasal symptoms at work than administrative staff working in healthcare sector. This risk was particularly marked during disinfection tasks and when exposure to QACs. Exposure to QACs increased significantly the risk of reported physician-diagnosed asthma and nasal symptoms at work (adjusted OR = 7.5 and 3.2, respectively). No significant association was found with other exposures such as latex glove use, chlorinated products/bleach or glutaraldehyde. CONCLUSION: RNs and ANs presented a higher risk of reported asthma than administrative staff. The highest risk was associated with tasks involving dilution of disinfection products by manual mixing, suggesting possible exposure to repeated peaks of concentrated products known to be strong respiratory irritants. Workplace interventions should be conducted to more clearly determine QAC exposure and improve disinfection procedures.

Ragweed pollen in France: origin, diffusion, exposure.

PURPOSE OF THE STUDY: To detect the origin of ragweed pollen and to measure the impact of this pollen exposure on allergic patients, so their sensitivity can be noted (using specific IgE production: sIgEw1) in order to inform the population about an "allergy" against those ragweed pollen grains. MATERIAL AND METHODS: To measure population exposure to ragweed pollen, the R.N.S.A (National Aerobiological Monitoring Network, a French association) has a pollen trap network located in urban areas. These traps allow continuous recording of airborne pollen, the light microscope analysis (with a bi-hourly time step) allows one to know the daily concentrations of ragweed grains and the circadian rhythm of grains impaction. It is thus possible to follow the evolution of pollination during each day ofeach season and to compare seasons and years at each station. Biomnis is a biological laboratory which performs more than 85% of ragweed specific IgE assay in France. It seems to be clear that when allergists ask ragweed IgE for a patient, it is because they think that this patient seems to be allergic to this specific pollen. The statistical analysis of results about specific IgE (for ragweed) from the Allergology laboratories Biomnis (located in Lyon and Paris) can determine the number ofpatients sensitized to ragweed in French departments. RESULTS: The distribution ofsensitized patients to ragweed is compared to ragweed pollen distribution studied by the R.N.S.A from the year 2005 to 2008 in France, whatever the ragweed plant' origin: local (closed topollen trap) or imported (by wind). CONCLUSION: The biological database (Health impact) allows a correlation between the geographical distribution ofragweed pollen and the number ofpatients with specific IgE against ragweed (sIgEw1), i.e., whose sensitization is due to local plants. That also permits one to estimate the expected number of allergy cases in the next years, because the sensitivity precedes the allergy.

Peanut allergy diagnosis in the context of grass pollen sensitization for 125 patients: roles of peanut and cross-reactive carbohydrate determinants specific IgE.

BACKGROUND: In vitro testing for food allergy may yield clinically irrelevant results due to cross-reactive carbohydrate determinants (CCD) specific immunoglobulin E (sIgE) induced by pollen exposure. The performances of 2 in vitro methods were evaluated for peanut sIgE measurement in patients allergic to grass pollen with or without subsequent allergy to peanuts. The correlation between clinically irrelevant peanut sIgE and the presence of CCD sIgE was investigated. METHODS: In vitro measurement of peanut sIgE was performed using the Pharmacia ImmunoCap system Radio Immuno Assay (RIA) and the Immulite 2000 3gAllergy system. Discrepancies between in vitro results and peanut allergy diagnosis were evaluated by measurement of CCD sIgE using bromelain and ascorbic acid oxydase (AAO). RESULTS: The sensitivity was 100% with both systems for the diagnosis of allergy to peanut (58 patients), nevertheless the specificity obtained with Immulite (73%) was better than that obtained using ImmunoCap (46%) in patients who were not allergic to peanuts, but who had a grass pollen allergy (n = 41). In 22 out of 41 patients who presented clinically irrelevant peanut sIgE results using ImmunoCAP, CCD sIgE was detected in 72% of the cases by bromelain and in 86% by AAO. In 11 patients out of 41 who presented irrelevant peanut sIgE results using Immulite, CCD sIgE was detected in 81% of the cases by bromelain and in 100% by AAO. CONCLUSION: The Immulite 2000 system had better specificity than the ImmunoCap system for accurate diagnosis of peanut allergy in patients allergic to grass pollen. CCD sIgE was identified in most of the false-positive peanut sIgE results.

Systematic follow-up increases incidence of anaphylaxis during adverse reactions in anesthetized patients.

BACKGROUND: The incidence of hypersensitivity reactions during anesthesia is underestimated because clinical symptoms may vary and diagnosis is not obvious. Our aim was to investigate the consequences of a systematic follow-up of patients on the estimated incidence of allergic reactions during anesthesia. METHODS: We conducted a prospective study over a 2-year period (70,000 anesthesias). When patients were suspected with hypersensitivity reactions or with unexplained adverse reactions during anesthesia, blood was sampled to measure histamine and tryptase, and then skin tests were performed 4-6 weeks later. RESULTS: During the studied period, 39 patients were enrolled in the database. Eight were excluded because of lack of skin tests. Twenty-two patients had clinical features compatible with immediate hypersensitivity reaction, and nine had reactions rated as 'unexplained' by the attending physician. Following systematic investigation, we found 22 hypersensitivity reactions (15 patients with obvious and seven with unexplained reactions) during anesthesia. This increases the estimated incidence of hypersensitivity reactions from 1 : 4667 to 1 : 3180 anesthesias. Tryptase concentrations were increased in only 50% of these patients. In our series, positive and negative predictive values of tryptase at T(0) for the diagnosis of anaphylaxis were 100% and 60%, respectively. Latex was the major causative agent, followed by neuromuscular blocking agents and antibiotics. CONCLUSIONS: Systematic follow-up of patients with unexplained reactions during anesthesia increases the estimated incidence of IgE-mediated hypersensitivity reactions during anesthesia by 50%.

Human serum IgE-mediated mast cell degranulation shows poor correlation to allergen-specific IgE content.

BACKGROUND: Although allergen-specific IgE content in serum can be determined immunochemically, little is known about the relationship between this parameter and the strength of the degranulation response upon allergen triggering. OBJECTIVES: Analyse the degranulation capacity of immunochemically defined purified and serum IgE after challenge with anti-IgE or allergen using a rat mast cell line (RBL) transfected with the alpha-chain of the human high-affinity IgE receptor (FcepsilonRI). METHODS: Purified IgE specific for 4-hydroxy-3nitrophenylacetyl, purified IgE of unknown specificity, and sera from allergic patients sensitive to Dermatophagoides pteronyssinus and Dactylis glomerata were assessed. Degranulation was measured by a beta-hexosaminidase release assay after anti-IgE or allergen-specific challenge. RESULTS: For purified monoclonal IgE a significant correlation (r = 0.97) was found between the proportion of bound allergen-specific IgE and the strength of the degranulation response. In contrast, no correlation (r = 0.27) was detected after sensitization with serum IgE. CONCLUSION: Our studies demonstrate that mast cell activation mediated through IgE from allergic patients is a result of complex relationships that are not only dependent on allergen-specific IgE content but also relate to the capacity to efficiently sensitize and trigger the signalling responses that lead to degranulation.

Flow cytometry versus histamine release analysis of in vitro basophil degranulation in allergy to Hymenoptera venom.

BACKGROUND: Flow cytometry (FCM) has been proposed for specific allergy in vitro testing. We investigated its biological significance for allergy to Hymenoptera venoms and compared it with the routinely performed basophil histamine release test (HRT). METHODS: Blood samples from 26 allergic and 8 nonallergic donors were incubated with venom at serial concentrations. Basophils were analyzed with anti-CD45-PE-Cyanin 5, Anti-IgE-FITC, and Anti-CD63-Phycoerythrine. HRT was measured by radioimmunoassay. RESULTS: FCM was as convenient as HRT for measuring basophil reactivity in at least 87% of allergic and 75% of nonallergic subjects. CD63 outer expression was specifically induced in 91% of releaser subjects (86% on HRT) and in 1 of 10 tests in nonallergic donors, or one of six tests (16% on HRT) in allergic patients tested with an irrelevant allergen. Both methods were concordant in 85.7% of the tests. The three discordant patients had low-grade reactions and borderline biological responses on FCM (n = 2) or HRT (n = 1). CONCLUSIONS: The dynamic, physiologic significance of CD63, the dose-response curve, and dependency on ethylene-diaminetetra acetic acid suggested that both tests reflect the same mechanism.

Anaphylactic shock induced by gadoterate meglumine (DOTAREM).

The use of contrast agent for magnetic resonance imaging improves the effectiveness of this diagnostic examination. Complexes of godolinium, which appear to be well tolerated, are used for this purpose. A few cases of anaphylactic shock have been attributed to these agents. We report a case of anaphylactic shock due to gadoterate meglumine (DOTAREM). While undergoing a magnetic resonance imaging examination, a 33-year-old nonatopic female patient became severely hypotensive, lost consciousness, and had generalized erythema immediately after the intravenous injection of this product. She recovered rapidly after she was given injection of epinephrine and her blood volume was restored with intravenous fluids. That DOTAREM had caused this immediate hypersensitivity reaction was proven by the positivity of prick-test and intradermal test at 10-3 (0.37 mg/ml) and in vitro leukocyte histamine release test. The results of these tests indicated that it was the gadoteric acid rather than the meglumine component of DOTAREM that was responsible: positivity of IDR at 10 mg/ml. Skin tests and leukocyte histamine release test to gadopentetate dimeglumine (MAGNEVIST) were negative. In addition of the exceptional character, this observation provides evidence for an immediate hypersensitivity without cross reactivity with gadopentetate dimeglumine.

Prevalence of muscle relaxant sensitivity in a general population: implications for a preoperative screening.

BACKGROUND: Muscle relaxants (MR) are responsible for 59% of peroperative anaphylactic reactions. A major issue would be to determine whether a systematic preoperative screening in the general population should be recommended. OBJECTIVE: The purpose of the study was to evaluate the prevalence of muscle relaxant sensitivity in a sample of the general population and to assess the role of possible risk factors. METHODS: Two hundred and fifty-eight subjects, aged 20-40 years, visiting a health care centre for a check-up were evaluated. Protocol included a questionnaire (occupation, symptoms of atopy, previous surgery, history of drug allergy), skin-prick tests to four commercial muscle relaxants and measurement of specific IgE against quaternary ammonium ions. Atopy was evaluated by skin-prick tests to common inhalant allergens and by a Phadiatop test. RESULTS: Of the study group, 9.3% had either a positive skin test to one or more muscle relaxant or a presence of specific IgE to quaternary ammonium ions. No risk factor was identified in the studied group. CONCLUSION: Since the rate of MR sensitivity is much higher than the anticipated rate of peroperative reactions due to allergy, a systematic preoperative screening for MR allergy should not be recommended for adults in a general population.

Cross-reactivity between terrestrial snails (Helix species) and house-dust mite (Dermatophagoides pteronyssinus). II. In vitro study.

Epidemiologic and in vitro data have shown that the association of house-dust mite (HDM) allergy and snail allergy in the same patients was due to cross-reactivity between HDM and snail allergenic components. However, the cross-reacting allergen(s) have not yet been identified. In vitro reactivity of seven patients' sera to the various extracts and hemolymph of four different Helix snail species was analyzed by IgE detection and immunodots and Western blots. Cross-reactivity between snails and Dermatophagoides pteronyssinus was assessed by immunodot and ELISA inhibition in two patients. Heterologous inhibition of the snail immunodot and ELISA was observed in one serum. Western blotting showed a specific binding on all four snail species extracts; molecular weights of snail allergens ranged from < 21 to 200 kDa. Marked individual differences were observed in the seven sera under study; most sera demonstrated IgE recognition of multiple bands, illustrating that no single allergen is responsible for cross-reactivity between snail and mite. These results confirm that cross-reactivity exists between snails of the Helix genus and HDM. This cross-reactivity, involving more than a single allergen, may be of clinical significance in atopic patients allergic to D. pteronyssinus. The identity of the cross-reacting allergens remains to be determined. Potential candidates include the thermostable minor allergens of D. pteronyssinus, tropomyosin and hemocyanin.

Prevalence of latex sensitization in subjects attending health screening: implications for a perioperative screening.

BACKGROUND: Because latex is a common allergen, the rate of latex sensitization may be high in the general population. A major issue would then be to determine whether a systematic preoperative screening in the general population should be recommended. OBJECTIVE: The purpose of the study was to evaluate the prevalence of latex sensitization in a sample of the general population and to assess the role of possible risk factors. METHODS: The subjects were 258 people, aged from 20 to 40 yr, visiting a health care centre for a check-up. The protocol included: a questionnaire (occupation, symptoms of atopy, use of latex goods and possible reactions, history of previous surgery), a skin-prick test, and a CAP RAST to latex. Atopy was evaluated by a skin-prick test to common allergens and a Phadiatop test. RESULTS: Some 6.6% of the study group had either a positive skin test or a positive RAST to latex. These subjects had a four-fold higher prevalence of symptoms when wearing gloves. The rate of latex sensitization was higher by fivefold in subjects with a history of reactions to latex goods and by fourfold in atopic subjects. CONCLUSIONS: Because the rate of latex sensitization is much higher than the anticipated rate of perioperative reactions due to latex allergy, a systematic preoperative screening for latex allergy should not be recommended for adults.

Hypersensitivity to banana in latex-allergic patients. Identification of two major banana allergens of 33 and 37 kD.

BACKGROUND: Allergy to banana often occurs in patients sensitized to latex. The spectrum of IgE-mediated responses to latex allergens is more and more documented but banana allergens and epitopes shared by these two allergens have not yet been characterized, even though the existence of cross-reacting IgE antibodies has been demonstrated. OBJECTIVE: The purpose of this study was to assess the relationship between banana hypersensitivity and latex allergy in a population of 19 latex-allergic patients and to identify allergenic components in banana and the common structures shared with latex. METHODS: The in vivo study was conducted in our outpatient department in patients with well-documented latex allergy. Clinical histories were evaluated and skin prick tests were performed with banana and latex extracts. IgE responses from 19 patients were investigated by means of CAP RAST assay and SDS PAGE immunoblotting. Epitopes shared by banana and latex were investigated by means of immunoblotting experiments. RESULTS: Eight of 16 patients (50%) reported symptoms after eating bananas and banana skin prick tests were positive in 5 of 14 patients (36%). Banana RAST results were positive in 12 of the 19 patients (63%). In immunoblot experiments, 17 of the 19 patients (89%) exhibited specific banana IgE antibodies and 16 allergenic components were identified with molecular weights ranging from 17 to 128 kD. Two were considered as major allergens: 33 kD was detectable in 15 of 19 sera (88%) and 37 kD in 13 of 19 sera (76%). Inhibition studies by preincubation of two individual sera with banana or latex extract demonstrated the complete disappearance of IgE binding on banana blotted allergens. CONCLUSION: This study confirms the "latex-fruit syndrome" already described by Blanco et al. Two major allergens were revealed in banana at 33 and 37 kD and the presence of more than ten common components with latex was observed.

Hypersensitivity to latex and Ficus benjamina allergens.

BACKGROUND: Association between allergy to Ficus benjamina and Hevea brasiliensis, two botanically unrelated plants, was suspected in consequence of two clinical observations. Symptoms were rhinitis and asthma. This study was undertaken to assess the in vivo and in vitro cross-reactivity between Ficus benjamina and Hevea brasiliensis allergens. METHODS: The two patients were asked about use and contact with latex devices and relationship between symptoms and Ficus benjamina exposure. Skin prick tests were performed with Ficus benjamina, Hevea brasiliensis extracts and common allergens. Double-blind nasal and bronchial challenge tests were done using the rinse fluid from a brand of latex gloves. Total and specific IgE antibodies to Ficus benjamina and Hevea brasiliensis were determined. In vitro cross-reactivity was investigated by means of CAP RAST and immunodot inhibition experiments. RESULTS: We observed that for the first patient the primary phenomenon is probably allergy to latex followed by allergy to Ficus benjamina. For the second patient, allergy to Ficus benjamina was diagnosed (improvement related to the avoidance of exposure to Ficus benjamina allergens) and positivity to latex skin prick tests may be due to the cross-reacting allergens. In vitro assays showed specific IgE antibodies to both allergens and cross-reactivity was confirmed in the two cases by reciprocal inhibition of the two extracts. CONCLUSION: The increasing risk of sensitization to widely used latex devices and extensive exposure to Ficus species in households and offices indicates increased allergenic risk from this newly recognized cross-reactivity.

Histamine release assay and radioimmunoassay for the detection of IgE antibodies against neuromuscular blocking drugs.

It is well established that muscle-relaxant drugs may be responsible for anaphylactoid reactions during anaesthesia. In the present work we evaluated in 41 patients who had experienced anaphylactoid reactions during general anesthesia, the value of different radioimmunoassays (RIAs) and of an histamine release assay (HRA). The RIA was performed with different solid phases as PAPPC (para amino phenyl phosphoryl choline), morphine, TMA (trimethylamine) and TEA (triethylamine). The results were expressed as the percentage of 125I anti-human IgE adsorbed onto the solid phase. The sensitivity was estimated respectively at 95, 82, 93 and 64%. The results were significantly in accordance with those obtained with QAS-RIA (from Guéant) but a weak correlation was seen with Phadebas Rast succinylcholine (r = 0.85 and 0.53 respectively). The HRA gave with the NMBD incriminated a sensitivity of 88%. The correlation between HRA and IDR for the drug involved was 89% and 43% for the other NMBDs. The PAPPC RIA was apparently the most efficient test to screen sera for the presence of IgE antibodies whatever the NMBDs involved in anaphylaxis. An advantage is that this solid phase is commercially available and therefore this RIA can be used routinely with a high sensitivity, allowing the comparison of the results obtained by different laboratories.