Differential expression of allergens on the internal and external surfaces of latex surgical gloves

BackgroundDifferences in latex allergen sensitization profiles have been described between children undergoing repeated surgical interventions and health care workers. The purpose of this study was to determine whether such sensitization profiles are associated with differences in the expression of latex allergen between the internal and external surfaces of surgical gloves.MethodsExtracts were obtained from whole surgical gloves as well as from their external and internal surfaces. The extracts were centrifuged, filtered, concentrated, dialyzed and lyophilized. The protein profile of the extracts was analyzed using hydrophobic interaction chromatography (HIC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting was performed using era from two patients with confirmed latex allergy. Latex recombinant allergen-specific IgE in these two patients was determined using a fluorescence enzyme immunoassay (FEIA) method. Latex allergen quantification was determined on both glove surfaces using an ELISA method.ResultsHIC and SDS-PAGE showed qualitative and quantitative differences in proteins between the internal and external glove surfaces, with the former being much richer in proteins. Immunoblotting of glove extracts using sera from two latex-allergic health workers showed differences between glove surface extracts. ELISA quantification of latex allergens demonstrated that the internal glove surface had high amounts of Hev b 5 and Hev b 6.02 whereas the external surface showed Hev b 1, Hev b 3, and Hev b 6.02.ConclusionsOur results reveal substantial differences in the composition of latex allergen profiles between the internal and external surfaces of surgical latex gloves, which may suggest a relationship between latex allergen localization and sensitization routes in different risk groups.     

Natural rubber latex allergy and asthma

Allergic responses to natural rubber latex (NRL) continue to be reported. In adults, the major exposure is in the occupational setting, especially in relation to NRL glove use by health care workers. Issues addressed over the past year include improving diagnostic methods for NRL allergy and characterization of NRL allergens relevant to various exposure groups and evaluating strategies for prevention and early detection of NRL allergy. Assessment of in vitro tests show good intertest correlation but lower sensitivity compared with skin test responses. NRL allergens have been further characterized as reported in the past year. Development of recombinant Hev b 3, a major NRL allergen relevant to children with spina bifida, enhances the likelihood for improved diagnostic reagents. Preliminary reports of primary preventive strategies suggest that avoidance of high-protein, powdered gloves in health care facilities can be cost-effective and is associated with a decline in sensitized workers.     

Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens.

Six Hevea brasiliensis latex protein allergens, Hevb 1, Hev b 2, Hev b 3, Hev b 4, and two variants of Hev b 7 (7b and 7c), were purified from Hevea latex, while a seventh protein, Hev b 5, was prepared in recombinant form. The presence of these proteins in glove extracts was indicated by their respective antibodies in the serum of rabbits immunized against the extracts. The relative propensities of IgE binding to the individual latex allergens were compared using sera from latex-allergic patients. IgE recognition of Hev b 4, Hev b 7b, Hev b 5 and Hev b 2 was most frequently encountered, with 75, 61, 31 and 28%, respectively, of the patient sera reacting. Sensitivity to multiple latex proteins was common, and out of the 31 seropositive patients, 23 (74%/ ) had IgE against at least two latex allergens, while 12 (39%) had IgE specific for at least three allergens. Statistical analysis of the data suggested that many patients might have acquired sensitivity to Hev b 2, Hev b 4 and Hev b 7b from a common source. (e.g., from latex products). On the other hand, sensitivity to Hev b 5 and to Hev b 7c were interrelated. It is plausible that sensitivity to these two proteins might have been acquired from sources other than latex products (e.g., from certain foods).     

Latex-vegetable syndrome due to custard apple and aubergine: new variations of the hevein symphony.

An increasing number of vegetables with crossreactions to latex are being described in patients with latex-vegetable syndrome. We present two of these vegetables, custard apple linked in two previous cases with latex sensitisation, and aubergine, that had not been described up to now in patients with latex sensitisation. The diagnosis of both cases was based on the clinical history, positive skin prick test (SPT) and specific IgE to the offending vegetables, as well as to positive SPT and specific IgE levels to latex and the major fruits involved in the latex-fruit syndrome (avocado, banana, and chestnut). Further, crude extracts from latex, custard apple and aubergine, as well as the purified allergens Hev b 6.02 and Prs a 1 were used in in vitro and in vivo assays: IgE immunodetection, histamine release (HRT) and basophil activation (BAT) tests and skin prick tests. In case 1, both purified Hev b 6.02 and Prs a 1 induced positive responses in skin prick tests, high levels of basophil activation and histamine release. Specific IgE immunodetection uncovered a reactive band of 45 kd in the crude custard apple extract, which was also recognized by anti-chitinase monospecific antibodies. The serum from patient 1 also detected Prs a 1 in immunodetection. Hev b 6.02 produced positive skin responses and showed high biological activity in HRT and BAT in the case of patient 2. However, Prs a 1 was reactive neither in SPT nor in IgE immunodetection. In fact, no band was detected using the serum of patient 2 in avocado or aubergine extracts. By contrast, Prs a 1 reached high values of basophil activation and over 10% of histamine release in case 2.     

Follow-up study of latex-allergic health care workers in Japan.

BACKGROUND: While many cases of latex allergy have been reported in Japanese health care workers (HCWs) since 1992, there have been no follow-up studies after removing latex from the workplace. We had previously replaced all working environment latex gloves and latex products with low-allergen or non-latex products. The purpose of the investigation was to evaluate the benefits of the latex allergy countermeasures that were taken in our hospital, and the effects of life guidance education. METHODS: We investigated 16 latex-allergic HCWs in our hospital. We gave them a detailed questionnaire and tested them by a skin prick test (SPT) with latex extract and specific IgE antibodies against latex using the Pharmacia CAP RAST system, RAST FEIA. We compared these results with earlier results from the time of diagnosis. RESULTS: According to the questionnaire, none of the HCWs had changed their work habits, though all were avoiding the use of latex products as much as possible. Of the 16 patients, 81.2% were eating foods for which cross reactivity with latex has been reported. However, the foods had not induced severe allergic symptoms. In the SPT, 62.5% of scores decreased and 81.2% of patients had decreases in specific IgE antibody levels. CONCLUSIONS: After avoiding latex products and following our educational suggestions, the patients' allergy symptoms had generally improved. This indicates that our countermeasures against latex allergy were largely successful.     

In vitro diagnostic evaluation of patients with inhalant allergies: summary of probability outcomes comparing results of CLA- and CAP-specific immunoglobulin E test systems.

For the diagnosis of allergy, presence of allergen-specific immunoglobulin E (IgE) usually is established either by allergen skin tests or by in vitro allergen-specific IgE measurements. However, in vitro assays of specific IgE often are modified as manufacturers improve allergens or change reagents to optimize test performance, affecting the diagnostic performance of in vitro allergen-specific IgE assays. This investigation compares the diagnostic outcomes of the Hitachi Chemical Diagnostics chemiluminescent assay (CLA) and Pharmacia, capsulated hydrophilic carrier polymer (CAP) in vitro allergen-specific IgE test methods in patients with inhalant allergy to a panel of selected allergens. Sera were obtained from 60 consecutive patients who had a clinical history suggesting inhalant allergy and were evaluated by allergen skin-prick test (SPT). Only patients with clinical findings of allergic asthma or rhinoconjunctivitis were included. Sera from patients with at least one positive SPT, which clinically correlated with the case history, were used for specific IgE measurements. Sensitivity and specificity were defined as conditional probabilities describing performances of the CAP system and the CLA system in reference to a standard composed of a combination of allergen-specific symptoms and a positive SPT. A test concordance of 79% was found between the CLA and CAP test results with a correlation coefficient of 0.8. Allergen-specific IgE assay sensitivity of the CLA and CAP systems was similar and allergen dependent, ranging from 67 to 100%. Assay specificity ranged from 39 to 86% for the CLA system and from 36 to 81% for the CAP system. When comparing the specific IgE results with allergen SPTs, 75% (+/- 3%) of CLApositive patients had a positive SPT, and 92% (+/- 4%) of CAPpositive patients had a positive SPT. Eighty-four percent (+/- 4%) of CLAnegative patients had a negative SPT, whereas 69% (+/- 5%) of CAPnegative patients had a negative SPT. The overall concordance between skin tests and in vitro tests was 76% for CLA and 67% for CAP. CLA and CAP score values showed good correlation and both tests may be useful when skin tests cannot be performed to identify subjects with IgE-mediated allergy. The CLA and CAP assays for allergen-specific IgE may be useful as part of an initial allergy evaluation because of the high negative predictive value of negative test results. For the majority of allergens the sensitivity was high. However, the specificity of both in vitro tests was low, indicating that positive in vitro test results should be evaluated carefully in conjunction with clinical symptoms and allergen-specific skin tests to determine the clinical relevance of the allergen sensitization.     

IGE-mediated natural rubber latex allergy: an update

In the past 2 decades, IgE-mediated NRL allergy has become a well-defined condition with recognised risk groups, established diagnostic tools, and adequate prevention strategies (1-3). Furthermore, molecular biology and biochemical techniques have significantly improved our knowledge of the proteins responsible to cause the disease. Clinical manifestations will not be addressed in this review, nor will broad preventive strategies be proposed; these have been discussed elsewhere (4, 5). After a brief introduction this review will focus on specific issues: (1) How do we estimate the prevalence of NRL allergy and who is at risk for clinical sensitisation? (2) What specific allergens cause NRL allergy? How does sensitisation for these allergens occur? Are all patients sensitised for the same allergens? Threshold allergen exposure levels. (4) What is the latex-fruit syndrome? What is the clinical relevance of a positive plant food specific IgE quantification in patients with NRL allergy? (5) How do we diagnose NRL allergy? What are the strengths and weaknesses of currently available diagnostic tools? (7) How do we manage NRL allergy? What is the role of medication and immunotherapy in the treatment of NRL allergy? How do we select an appropriate non-NRL alternative for NRL gloves? Which regulatory provisions have been implemented?     

Prevalence of latex allergy and evaluation of some risk factors in a population of atopic children.

The aims of our study were to evaluate (1) the prevalence of natural rubber latex (NRL) allergy in an unselected population of atopic children; (2) the diagnostic efficacy of skin prick tests (SPTs) with latex extracts; (3) the correlation between positive SPTs to latex and risk factors such as atopy, fruit allergy, history of surgery cares or dental cares. We randomly enrolled 151 unselected atopic and 59 nonatopic children who underwent SPTs with common inhalant and food allergens, and SPTs with two different latex extracts. A clinical history concerning allergic history, symptoms after contact with latex objects or after ingestion of fruits or vegetables, dental and surgical treatments was obtained. Six of the 151 atopic children were positive to latex SPTs, but only one out of 59 nonatopic children was positive to latex SPTs. Concerning risk factors, 86% of children with SPT positive to latex were atopic, 71.4% had a clinical history of surgery, and none of them had undergone dental or orthodontic treatments. The prevalence of NRL sensitization in our unselected population of atopic children was 3.9%, but the prevalence of NRL allergy was 2.6%. Concerning NRL allergy, the sensitivity and the specificity of SPTs with latex extracts are high (1.00 and 0.98, respectively), as well as negative predicting value (1.00); the positive predictive value is low (0.70). We conclude that atopy, surgical treatments, and sensitization to foods cross-reacting with NRL are important risk factors for NRL sensitization. We have no data concerning dental or orthodontic cares.     

Characterization of a mouse model of allergy to a major occupational latex glove allergen Hev b 5

Allergen-specific immunotherapy is a clinically proven effective treatment for many allergic diseases, including asthma; however, it is not currently available for latex allergy because of the high risk of anaphylaxis. There is, therefore, a crucial need for an animal model of latex allergy in which to develop effective immunotherapy. Previous mouse models of latex allergy either did not characterize the allergic pulmonary immune response or used crude latex extracts, making it difficult to quantify the contribution of individual proteins and limiting their usefulness for developing specific immunotherapy. We immunized mice with recombinant Hev b 5, a defined major latex allergen, or latex glove protein extract, representing the range of occupationally encountered processed latex allergens. The immune response was compared with that seen in ovalbumin-immunized mice. Immunization with Hev b 5 or glove extract elicits hallmarks of allergic pulmonary Th2-type immune responses, comparable to those for ovalbumin, including (1) serum antigen-specific IgE, (2) an eosinophilic inflammatory infiltrate in the lung, (3) increased interleukin-5 in lung bronchoalveolar lavage fluid, and (4) mucus hypersecretion by epithelial cells in the lung airways. This mouse model will aid the development of potentially curative treatments for latex-sensitized individuals, including those with occupational asthma.     

Latex: a complex allergy

The authors review several of the most important aspects of latex allergy, an increasing problem in Public Health, which should be understood by all health professionals. After briefly presenting the history of the origin latex, from Hevea brasiliensis the authors describe the antigens of latex: Hev b1 to Hev b8, major allergens. They also note the crossed reactivity not only with foods, exotic fruits, but also with pneumoallergens and in particular the pollens. The groups at risk are essentially workers in the latex industry, health professionals and finally infants with spina bifida or other severe urological anomaly. The clinical signs are reactions of type 1 hypersensitivity, to urticaria and/or angio-oedema and anaphylactic shock. Diagnosis is based on a search for specific serum IgE, skin tests and provocation tests. Prophylaxis depends on removal of all substances that are based on latex, especially replacement of gloves with vinyl, but also on a food diet that excludes all foods that have a cross-reactivity with latex.     

Intraoperative anaphylactic shock in a child with no history of type I hypersensitivity

Natural rubber latex is the second most implicated agent in intraoperative anaphylactic reactions. This report describes a case of intraoperative anaphylaxis occurring in a non-atopic fourteen-year-old girl undergoing multiple surgical procedures, but without spina bifida, in which latex surgical gloves were the main culprit for the anaphylactic reactions. Clinical manifestations of an anaphylactic reaction were also experienced during the examination of the possible cause of intraoperative anaphylaxis by skin prick testing with a latex allergen extract. Skin tests with anesthetics were negative. Specific IgE to latex was positive at 92.9 kUA/L (class 5). The molecular basis for the reported intraoperative anaphylaxis was ascribed to three low-molecular mass latex allergens (10-15 kD) detected in the brand of latex surgical gloves used during the operation. Given the potential of a dramatic outcome, latex allergy testing as a regular preoperative measure may contribute to the reduction of anaphylactic reactions during surgical interventions.     

Addressing Molecular Diagnosis of Occupational Allergies

Purpose of Review

Numerous clinically relevant allergenic molecules enhance the performance of specific (s) IgE tests and improve the specificity of allergy diagnosis. This review aimed to summarize our current knowledge of the high-molecular-weight allergens involved in the development of occupational asthma and rhinitis and to critically analyze the contribution of component-resolved diagnosis in the management of these conditions.

Recent Findings

There is a lack of standardization and validation for most available extracts of occupational agents, and assessment of sIgE reactivity to occupational allergen components has been poorly investigated, with the notable exception of natural rubber latex (NRL) and wheat flour. In the case of NRL, the application of recombinant single allergens and amplification of natural extracts with stable recombinant allergens improved the test sensitivity. IgE-sensitization profile in patients with baker’s asthma showed great interindividual variation, and extract-based diagnostic is still recommended. For other occupational allergens, it remains necessary to evaluate the relevance of single allergen molecules for the sensitization induced by occupational exposure.

Summary

Progress has been made to characterize occupational allergens especially NRL and wheat, although there is still an unmet need to increase the knowledge of occupational allergens, to include standardized tools into routine diagnostic, and to evaluate their usefulness in clinical practice.

     

Overview of Serological-Specific IgE Antibody Testing in Children

Allergic diseases are among the most common chronic conditions in the pediatric population. Allergy diagnostic testing is an important part of the evaluation/management of allergic patients because the history may not be precise enough to identify the specific allergen sensitivity. In addition to providing information about specific sensitivities, allergy diagnostic tests have some predictive value in terms of future risk of developing an allergic condition and the severity/persistence of the allergic disease. The two most commonly used methods of confirming allergen sensitization are skin testing and measurement of serum-specific IgE. Both methods have similar diagnostic value in terms of sensitivity and specificity, with both parameters varying with the clinical scenario and allergen tested. Currently, there are three US Food and Drug Administration–cleared, serum-specific IgE assays used in the United States. The three assays report comparable analytic sensitivity, with the coefficients of variation of the precision, reproducibility, and linearity being less than 15%. However, comparative studies have demonstrated significant inter-assay variability, suggesting that they detect different populations of IgE antibody in human sera or do not measure the same antibodies with the same efficiency. Current specific IgE assays utilize allergen extract reagents. Testing with these reagents may identify sensitivity to clinically irrelevant allergens. This diagnostic limitation has spurred the development of molecular diagnostic tests, also referred to as component-resolved diagnostics, which utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules. These advancements in serum IgE testing may enhance the precision of allergy diagnostic testing, which may decrease the need for oral food challenges and improve the specificity of allergen immunotherapy.     

Patterns of skin prick test positivity in allergic patients: usefulness of a nationwide SPT chart review

BackgroundA previous survey on allergens used by Mexican allergists in their skin prick test (SPT) panel showed wide variation. Humidity varies in different zones of Mexico. This might lead to differences in natural exposure and allergic sensitisation throughout the country. We aim to describe the SPT sensitivity patterns in the different climatic zones in Mexico and to show the usefulness of a structured SPT chart-review including multiple clinics in obtaining these allergen sensitisation patterns.Methods: A retrospective, structured chart-review of SPT results was undertaken in allergy clinics throughout Mexico. Ratios of SPT positivity were calculated for individual allergens, per climatic zone and nation-wide. Per allergen group the most important allergens were identified. Statistically significant differences between zones and the nation-wide data were tested with Pearson's Chi-squares test.Results4169 skin test charts were recollected. The most important allergens causing sensitisation were very similar in different zones, despite climate variation. The allergen with highest ratio of SPT positivity was Dermatophagoides pteronyssinus (51%), with trees (Ash-27%, Alder-22%, Oak19%), and Bermuda grass (26%) as second and third. In the hot zones (humid and dry) Aspergillus was statistically significant more frequently than in more temperate zones. Cockroaches thrive in big cities and humid zones and Mesquite and Poplar in dry zones. Weeds are less important.ConclusionMexico has its own SPT sensitisation pattern, which is different from America and Europe. A structured chart-review of SPT results is able to show this and might be a tool for allergists in other countries.     

Prevalence of IgE antibodies to an extract from rubber tree (Hevea brasiliensis) latex and recombinant pollen allergens (Phl P 1, Phl P 2, Phl P 5, Bet v 1 and Bet v 2) in the sera of Italian atopic patients

BackgroundPrevious studies have reported cross-reactivity between latex and grass allergens. Inhibition studies have indicated cross-reactivity of IgE with latex and grass pollen proteins. A panel consisting of a few recombinant allergens, namely rPhI p 1, rPhl p 2, rPhl p 5 and profilin, was sufficient to diagnose grass pollen allergy in patients allergic to grass pollen.MethodsSerum samples from 528 consecutive outpatients with IgE antibodies towards at least one allergen (IgE level > 0.35 kAU/L) were selected for this retrospective study. Total and specific serum IgE to rPhl p 1, rPhl p 2, rPhl p 5, rBet v 1, rBet v 2, latex, birch, hazel, mugwort, wall pellitory, Dermatophagoides pteronissinus, Alternaria tenuis, cat and apple were measured by the immunoenzymatic capsulated hydrophilic carrier polymer (CAP) FEIA system (Pharmacia & Upjohn).ResultsOf 123 polysensitized patients with antilatex Ig1E, 12 (9.76%) had symptoms after latex exposure. Ten of 12 subjects monosensitized to latex had symptoms after latex exposure. Symptomatic patients had higher IgE levels to latex than symptomless patients (P = 0.046). A higher prevalence of antilatex IgE was seen in sera containing specific IgE to rPhl p 1, rPhl p 5 and rBet v 2. A good correlation (Spearman's r = 0.52; P = 0.001) between high levels of antilatex IgE and total serum IgE was found.ConclusionsThe findings of the present study may support the concept that a high proportion of sera containing IgE to rBet v 2, rPhl p 1 and rPhl p 5 simultaneously contain antilatex IgE. Therefore, patients with specific IgE to these recombinant allergens with no history of current latex exposure may need additional evaluation.     

Latex allergen sensitization and risk factors due to glove use by health care workers at public health units in Florianopolis, Brazil.

BACKGROUND: Natural rubber latex allergy is a "new" illness whose prevalence has reached epidemic proportions in highly exposed populations such as health care professionals. OBJECTIVE: The aim of the study was to evaluate the frequency of reactions to latex and risk factors due to glove use in health care workers (HCW) in Florianopolis, Santa Catarina, Brazil. METHODS: We evaluated latex-related allergy in 260 HCW by means of a questionnaire, skin prick tests (SPT) and serum latex specific IgE antibody levels. The subjects were divided into two groups depending on level of exposure to latex gloves. Comparisons were made between the different variables and a risk score was calculated using logistic regression analysis. RESULTS: Glove-related symptoms were observed in 57% of 140 HCW. Significant differences between HCW and control groups were found for the following symptoms: contact dermatitis (P < .0001), cutaneous rash (P < .0001), asthma or allergic rhinitis (P < .0001), symptoms associated with toy balloons (P < .0001), airborne glove powder causing latex allergen reaction (P < .0001), food allergy (P < .0001), fruit allergy (P < .0001) and multiple surgical interventions (P = .0052). Contact dermatitis and anaphylaxis were the main problems, with a high risk factor for the development of latex allergy. Logistic regression analysis showed a significant positive association between the risk of latex allergy and those subjects who reported more than 4 positive answers on the questionnaire (including SPT) (odds ratio 6.8; 95% confidence interval 0.7-60.3). No latex-related allergy symptoms were reported by the control group. Serological latex specific immunoglobulin (Ig) E antibody levels were negative for both groups. CONCLUSION: It is essential to recognize which professionals are sensitized to latex in order to provide appropriate treatment and to establish adequate prevention.     

Component-Resolved Diagnosis for Phleum Allergy: The Role of Recombinants

Background. Conventional diagnostic tests (such as radioallergosorbent test [RAST] and skin prick test [SPT]) use native raw pollen allergen extracts to establish allergy. However, recombinant allergens may offer important advantages compared with their natural counterparts. Objective. This study evaluated serum immunoglobulin E (IgE) in patients with grass-induced allergic rhinitis (AR) or AR with asthma (ARA), comparing assays with natural or recombinant grass allergens. Methods. Sixty patients (33 AR, 27 ARA) positive with SPT and serum IgE for Phleum pratense were enrolled in the study. Serum IgE specific for conventional and recombinant Phleum pratense: rPhl p 1, rPhl p 2, nPhl p 4, rPhl 5b, rPhl p 6, rPhl p 7, rPhl p 11, rPhl p 12, were measured by the IFMA procedure (ImmunoCAP, Phadia, Uppsala, Sweden). Data were expressed as the median (md) and percentiles. Recombinant allergen results were expressed also as the percentage of positive concentrations. The Wilcoxon test was used to compare samples. Because diagnosis is a binary variable (AR/ARA), logistic regression analysis was performed to identify possible correlates. Results. IgE concentrations assessed with recombinant allergens were significantly higher in ARA patients (p = .05) than in AR patients. A value >5.8 kU/L is the optimal cut-off to discriminate AR and ARA patients. Model specificity was 76%, sensitivity 78%, and efficiency 77%. Conclusion. This study shows that IgEs for natural and recombinant grass pollen allergens are significantly higher in patients with AR and asthma. Moreover, using recombinant allergens it is possible to define a prediction model for diagnosis with 77% efficiency. Therefore, this study may suggest that there are advantages of using recombinant or purified, native allergens over crude extracts.     

Latex allergy: Review of recent advances

Latex allergy is an IgE-dependent immediate hypersensitivity reaction to latex proteins. Risk factors for latex allergy are contact with latex products and atopy. Children who undergo multiple surgical procedures and healthcare workers are the major groups at risk. Powdered latex gloves are an important source of sensitization. Preventive measures are leading to reduction in latex sensitization and allergic reactions. The prevalence of latex allergy in the general population may be as low as 0.1%, whereas the frequency of latex sensitization is reported to be 7%; this may be due to cross-reacting antipollen IgE. The most important latex allergens have been purified, and some have been cloned and sequenced. Many latex-allergic patients are also allergic to common plant-derived aeroallergens and foods. The structural and biologic relationships among plant-derived food allergens, including latex, explain these clinically important cross-reactions.     

Wheat flour allergy: an entire diagnostic tool for complex allergy

Wheat proteins are involved in respiratory allergy, contact allergy and food allergy. Wheat allergens involve in these pathologies are well-known. However, establishment of wheat allergy diagnostic can be sometimes difficult on account of the complex allergenic composition of skin prick test (SPT) solutions of wheat flour. Therefore, we have studied specific IgE reactivity from patient sera with wheat food allergy, and characterized allergenic composition of wheat SPT solutions by specific antibodies directed to wheat allergens. The results showed that 20 of the 25 sera analyzed contained specific IgE to at least one wheat protein fraction. Among positive sera, 75% have specific IgE to water/salt soluble fraction, 85% to native gluten fractions and 65% to wheat isolate fraction. The results showed also that SPT solutions of wheat flour contained major food allergens from each allergenic fraction. These results highlighted the importance of using fractions, which constitute the whole wheat allergenic pattern, during specific IgE reactivity analyses. Moreover, we have observed that wheat isolate extract (results of food industrial process) contained not only modified allergens (neo-allergens) involve of specific food allergy to wheat isolate but also some native allergens involve in wheat food allergy. Thus, these results showed the importance to use, for wheat in vivo diagnosis together wheat SPT solutions (gluten extract and wheat isolate) in order to differentiate wheat food allergy to specific wheat isolate allergy.     

Prevalence of latex sensitization in health care workers of a general hospital in Palermo, Sicily.

STUDY OBJECTIVE: To assess the prevalence of latex sensitization in a group of hospital employees in a general hospital. DESIGN: Cross-sectional study on hypersensitivity to latex gloves among health-care workers. SETTING: A general hospital in Palermo, Sicily. PATIENTS: 196 health-care workers answered a questionnaire about their case history of allergic diseases (i. e., rhinitis and/or asthma) and about symptoms after wearing latex gloves. All subjects were tested by skin prick test (SPT) with commercial latex extract and aeroallergens and had blood draw for total serum IgE and latex-specific IgE testing and glove-use test. MAIN RESULTS: 42% of the subjects who answered the questionnaire reported at least one symptom after wearing latex gloves. All symptoms were local, and none of the subjects reported systemic reactions. The most common symptom was itching, but none of subjects with only itching presented a positive SPT or specific serum IgE to latex. The SPT to latex was positive in 19 of 196 subjects (9.7%). Specific IgE to latex were found in 15/196 subjects (7.6%). Glove-use test was positive in 14/196 (7.1%). CONCLUSIONS: The overall prevalence of latex sensitivity in health-care workers in our epidemiological setting is 7.1%. An accurate diagnosis must take in account the integration of in vivo and in vitro tests with previous history of allergic disease.