Natural Rubber Latex Allergens Research Articles

Latex Allergens in the Ear Straps of Face Coverings and Masks in the UK: Initial Findings

The SARS-CoV-2 pandemic led to an unprecedented demand for PPE and generated a small-scale industry making personalised face coverings. Concerns had been raised about the use of natural rubber latex (NRL) as an elastomeric material, with its health risks. We have investigated the levels of four NRL allergens and total protein in elastomeric ear-straps in manufactured face coverings and the material sold for their production, and a number of imported N95/KN95 PPE masks. None of the samples identified whether NRL was involved or not. NRL allergens levels in manufactured masks were low or not detectable; 3/10 of the N95/KN95 masks showed levels above the limit of detection, probably reflecting low-level cross-contamination during manufacture. Three batches of material sold for “the manufacture of ear straps for face coverings” had significant but variable levels of allergen (250–2526 ng/g of material). Historically, extractable protein measurements have been used as an indicator of possible NRL proteins. This study showed significant levels of apparent protein in sample extracts without measurable NRL allergens or confirmation by electrophoresis. Therefore, the immunochemical measurement of NRL allergens remains key to rule out elastomeric material with the potential to cause latex-related health problems.

Evaluation of proteins in natural rubber latex gloves and pulmonary function amongst female nurses in two tertiary hospitals in southern, Thailand.

Inhaled natural rubber latex (NRL) allergens in a healthcare environment can cause NRL sensitization and reduce pulmonary functions. To determine the amount of proteins and the effects of NRL gloves on the pulmonary functions of female nurses in two hospitals in the southern Thailand. The study included 340 female nurses from two hospitals in which self-reported information and a blood sample were collected. NRL sensitization was determined by using a solid-phase enzyme-labeled fluoroenzyme-immunoassay for anti-NRLIgE antibodies. Proteins in NRL gloves were measured by a modified Lowry method. Pulmonary function was measured by a spirometer. The prevalences of respiratory effects self-attributed to NRL glove use and of NRL sensitization were 6.5 and 4.7%, respectively. Four of the 16 sensitized nurses reported respiratory symptoms. NRL sensitized nurses had lower forced expiratory flow (FEF25-75% predicted value) than those who were non-sensitized (Adj. difference = -12.56, 95% CI = -24.41 to -0.70). Furthermore, examination gloves contained protein levels in the range of 111-250 mg/dm2. Difference types of NRL glove contained with different amount of proteins.NRL sensitization was more prevalent in nurses with high concentrations of proteins in NRL gloves (p = 0.04). Sensitization to NRL was associated with a decrease in FEF25-75% predicted value, indicating narrowing of the small airways of the lung. Use of gloves with low proteins can reducing NRL allergen exposure in these hospitals, which may reduce the risk of developing respiratory problems and NRL sensitization.

Characteristics of hand eczema in final-year apprentice nurses during the COVID-19 pandemic.

BackgroundApprentice nurses are considered at high risk to developing occupational skin diseases.ObjectivesThis study assessed the frequency and origin of hand eczema, and work‐related risk factors in apprentice nurses.MethodsThe study involved 240 final‐year apprentice nurses (females 75%, median age 19 years) from vocational schools in Zagreb, Croatia. The study was performed in 2020/2021 and included a questionnaire and clinical examination by means of the Osnabrück Hand Eczema Severity Index (OHSI). Skin prick test (SPT) with natural rubber latex (NRL) allergen, and patch test with the basic series of allergens, and disinfectants, were performed in 42 apprentice nurses with hand eczema that lasted more than 3 months.ResultsClinically observed and self‐reported hand eczema were found in 49% and 46% of apprentice nurses, respectively. Those with observed changes were older and reported more days per month spent on practical work than those with healthy skin (P = .001). Median OHSI was 4 (interquartile range 2‐6). There were no positive SPTs to latex, and 11 (26%) apprentice nurses had positive patch test reactions to one or more tested allergens, mostly nickel.ConclusionsHand eczema was common in final‐year apprentice nurses during the COVID‐19 pandemic. It was mostly of irritative origin, associated with the duration of practical training, confirming cumulative effect of hazards on skin barrier.

Evaluation of proteins in natural rubber latex gloves and pulmonary function amongst female nurses in two tertiary hospitals in southern, Thailand.

BACKGROUND Inhaled natural rubber latex (NRL) allergens in a healthcare environment can cause NRL sensitization and reduce pulmonary functions. OBJECTIVES To determine the amount of proteins and the effects of NRL gloves on the pulmonary functions of female nurses in two hospitals in the southern Thailand. METHODS The study included 340 female nurses from two hospitals in which self-reported information and a blood sample were collected. NRL sensitization was determined by using a solid-phase enzyme-labeled fluoroenzyme-immunoassay for anti-NRLIgE antibodies. Proteins in NRL gloves were measured by a modified Lowry method. Pulmonary function was measured by a spirometer. RESULTS The prevalences of respiratory effects self-attributed to NRL glove use and of NRL sensitization were 6.5 and 4.7%, respectively. Four of the 16 sensitized nurses reported respiratory symptoms. NRL sensitized nurses had lower forced expiratory flow (FEF25-75% predicted value) than those who were non-sensitized (Adj. difference = -12.56, 95% CI = -24.41 to -0.70). Furthermore, examination gloves contained protein levels in the range of 111-250 mg/dm2. Difference types of NRL glove contained with different amount of proteins.NRL sensitization was more prevalent in nurses with high concentrations of proteins in NRL gloves (p = 0.04). CONCLUSION Sensitization to NRL was associated with a decrease in FEF25-75% predicted value, indicating narrowing of the small airways of the lung. Use of gloves with low proteins can reducing NRL allergen exposure in these hospitals, which may reduce the risk of developing respiratory problems and NRL sensitization.

The Clinical Relevance of Natural Rubber Latex-Specific IgE in Patients Sensitized to Timothy Grass Pollen

Background: In pollen-allergic patients, cross-reacting allergens including cross-reactive carbohydrate determinants (CCDs) and profilins may result in positive natural rubber latex (NRL)-specific IgE (sIgE) antibody tests but the relationship between this sensitization and clinical NRL type 1 allergy is poorly described. Objective: The aims of this study were to determine the frequency and clinical relevance of NRL sIgE in grass pollen-sensitized individuals and to investigate which NRL allergen components these individuals were sensitized to. Methods: A total of 383 grass-sensitized patients answered questions about NRL allergy symptoms and their stored sera from previous investigations were analyzed for NRL sIgE. Patients with NRL sIgE (n = 32) underwent further investigations comprising medical history, skin prick test with NRL and inhalational allergens, and an additional blood sample. The additional blood samples were analyzed for total IgE and sIgE against NRL, timothy grass, birch, rHev b 1, 3, 5, 6.01, 6.02, 8, 9, 11, rPhl p 12, and MUXF3, which was used as a marker of CCD sensitization. Results: Overall, 9.4% of all grass pollen-sensitized individuals showed IgE sensitization to NRL but only 1.6% had a confirmed type I NRL allergy. CCD and Hev b 8 explained the clinically irrelevant NRL IgE sensitization in 65% of the cases. We found a highly significant correlation between NRL profilin (Hev b 8) sensitization and grass profilin (Phl p 12) sensitization (p < 0.0001). Conclusions: Data from this study support the hypothesis that in patients with grass pollen sensitization, Hev b 8 mono-sensitization has little or no clinical relevance and is caused by cross sensitization from grass profilin (Phl p 12).

Allergen component analysis as a tool in the diagnosis and management of occupational allergy

We are now in the epoch of “molecular allergology” and numerous clinically relevant allergenic molecules are available improving the performance of in vitro allergen tests and allergen detection methods. This review is focusing on characterized occupational allergens and their implementation into the in vitro diagnosis for occupational allergy and in allergen detection methods.More than 400 occupational agents are identified and documented as being ‘respiratory sensitizers’, but currently only a limited number of them are characterized on the molecular level and available for routine diagnosis as native or recombinant allergens. One exception, however, is natural rubber latex (NRL) from Hevea brasiliensis still remaining an important occupational allergen source. Characterization of 15 NRL allergens led to the development of assays for the determination of allergen content of NRL materials and the implementation of component-resolved diagnosis (CRD) for specific IgE antibody measurement. Microarray or singleplex using recombinant or native allergens are reliable tools for NRL allergy diagnosis. In addition, NRL allergy is an excellent model for improving extract-based specific IgE measurement by amplification of NRL extract preparation with stable recombinant major allergen rHev b 5. Despite the many efforts to characterize the occupationally relevant wheat allergens for baker’s asthma, the most frequently occurring forms of occupational asthma, the results are highly diverse. Wheat sensitization profiles of bakers showed great interindividual variability and no wheat allergen could be classified as the major allergen. For diagnosis of baker’s asthma, a whole wheat extract is still the best option for specific IgE determination. But single wheat allergens might help to discriminate between wheat-induced food allergy, grass pollen allergy and baker’s asthma. For workplace-related allergens like coffee, wood, soybean, seafood and moulds allergens are characterized and few of them are available, but their relevance for occupational sensitization routes should be verified in the further studies.

Quantification of protein and latex allergen content of various natural rubber latex products.

Introduction: The use of natural rubber latex (NRL) products can cause IgE-mediated allergic reactions in exposed people. The aim of this study was to quantify the content of protein and latex allergens of currently available NRL products to estimate the allergenic potential of these products. Methods: 14 household articles (pacifiers, baby bottle nipples, condoms, household and disposable gloves, toy balloons, and Band-Aids) as well as 18 NRL examination gloves currently used by healthcare workers were investigated. Extracts of the examination gloves were prepared according to the standard method DIN EN 455-3, which contains requirements and testing for biological evaluation of single use medical gloves. The protein content was determined with a modified Lowry method. Latex allergen content was measured using an IgE-inhibition immunoassay with a mix of serum-sensitized patients as detection antibody sources and the latex ImmunoCAP as solid phase. The allergens Hev b 1, 3, 5, and 6.02 were determined using available immunoassays. Results: In 5 out of 18 examination gloves, the protein content was under the detection limit. The other 13 gloves contained protein between 7.1 and 92.3 µg protein/g material. Five glove brands contained protein concentrations above the recommended reference value of 30 µg protein/g material. Latex allergen could be measured in 12 out of 18 NRL gloves. In only 3 gloves could none of the allergens Hev b 1, 3, 5, and 6.02 be detected. Protein and Hev b 1 could be measured in the examined childcare products, while the concentrations of the latex allergens Hev b 3, 5, and 6.02 were mostly under the detection limit. Boiling of childcare products led to a reduction of protein and allergen content. In some of the other daily-used NRL articles, the protein and allergen contents were even higher than in gloves. Conclusion: Our study demonstrated that protein, and particularly latex allergens, were detectable in currently available examination gloves as well as in household articles whereby a risk for sensitization and/or induction of allergic symptoms could not be excluded.

Occupational Latex Allergy: the Current State of Affairs.

Allergy to natural rubber latex (NRL) reached epidemic proportions during the nineties and led to intense preventive efforts. The aim of this review was to provide a comprehensive compilation of the current status of occupational NRL allergy. Recent advances led to the characterization of 15 NRL allergens and the development of assays for measuring the allergen content of NRL materials and specific IgE antibodies against NRL allergen components. Preventive measures aimed at reducing workplace exposure to NRL allergens were associated with decreasing incidence rates of NRL allergy. However, a pooled analysis of epidemiological surveys published during the last 10years provided prevalence estimates of NRL sensitization and allergy similar to those derived from studies conducted before 2003. Substantial progress has been made in the understanding and prevention of NRL allergy, although the disease may still remain a worldwide cause of concern.

The role of allergen components for the diagnosis of latex-induced occupational asthma.

Recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergen components have been developed to assess the patients' allergen sensitization profile and to improve the diagnosis of NRL allergy. To examine whether the determination of specific IgE (sIgE) reactivity to a panel of recombinant allergen components would be helpful for diagnosing NRL-induced occupational asthma (OA) in predicting the outcome of a specific inhalation test. sIgE levels to NRL extract and 12 recombinant NRL allergen components were assessed in 82 subjects with OA ascertained by a positive specific inhalation challenge (SIC) with NRL gloves and in 25 symptomatic subjects with a negative challenge. The sensitivity, specificity, positive predictive value, and negative predictive value of a NRL-sIgE level ≥0.35 kUA /l as compared to the result of SICs were 94%, 48%, 86%, and 71%, respectively. The positive predictive value increased above 95% when increasing the cutoff value to 5.41 kUA /l. Subjects with a positive SIC showed a significantly higher rate of sIgE reactivity to rHev b 5, 6.01, 6.02, and 11 than those with a negative SIC. A sIgE sum score against rHev b 5 plus 6.01/6.02 ≥ 1.46 kUA /l provided a positive predictive value >95% with a higher sensitivity (79%) and diagnostic efficiency (Youden index: 0.67) as compared with a NRL-sIgE ≥5.41 kUA /l (49% and 0.41, respectively). In suspected OA, high levels of sIgE against rHev b 5 combined with rHev b 6.01 or 6.02 are the most efficient predictors of a bronchial response to NRL.

How should occupational anaphylaxis be investigated and managed?

Anaphylaxis is a systemic allergic reaction that can be life-threatening or fatal and can result from work-related exposures. This review study focuses on the assessment, main triggers, and management of occupational anaphylaxis. Exposed workers can be sensitized through inhalation and skin contact, and the risks increase with penetration of the allergen through the skin. The main eliciting agents of occupational anaphylaxis include stinging insects and animal bites, natural rubber latex and other vegetable allergens, food products, and drugs. Workers sensitized to occupational allergens may also develop anaphylaxis outside the work environment from exposure to the same or to cross-reacting allergens. Cofactors at work such as exercise may increase the risk. The relevant medical records and laboratory tests (e.g. tryptase) performed during the episode should be reviewed. It is very important to confirm the diagnosis and to identify the specific trigger of anaphylaxis. Component-resolved diagnosis may help in the identification of primary sensitizers or cross-reactive allergens. Adrenaline must be administered to all patients experiencing anaphylaxis. Removal from exposure is mandatory to prevent further episodes. A written emergency management plan, health and safety education, and training and surveillance should be enforced in occupations at greater risk.

Content of Asthmagen Natural Rubber Latex Allergens in Commercial Disposable Gloves.

The use of natural rubber latex (NRL) gloves in many occupations may lead to latex sensitization, allergic asthma, and skin reactions. Due to their good properties and environmental safety NRL gloves are still being used in the healthcare setting, but also in the food industry, by hairdressers, cleaners, etc. The aim of our study was to assess the protein and NRL allergen content in commercial gloves by different methods, including a new assay. Twenty commercially available NRL gloves were analyzed. Protein extraction was performed according to the international standard ASTM D-5712. Total protein content was measured with a modified Lowry method, NRL content with the CAP Inhibition Assay, the Beezhold ELISA Inhibition Assay, and an innovative ELISA with IgY-antibodies extracted from eggs of NRL-immunized hens (IgY Inhibition Assay). We found a high protein content in a range of 215.0-1304.7μg/g in 8 out of the 20 NRL gloves. Seven of the 20 gloves were powdered, four of them with a high protein content. In gloves with high protein content, the immunological tests detected congruently high levels of NRL allergen. We conclude that a high percentage of commercially available NRL gloves still represent a risk for NRL allergy, including asthma. The modified Lowry Method allows to infer on the latex allergen content.

Content of Asthmagen Natural Rubber Latex Allergens in Commercial Disposable Gloves.

The use of natural rubber latex (NRL) gloves in many occupations may lead to latex sensitization, allergic asthma, and skin reactions. Due to their good properties and environmental safety NRL gloves are still being used in the healthcare setting, but also in the food industry, by hairdressers, cleaners, etc. The aim of our study was to assess the protein and NRL allergen content in commercial gloves by different methods, including a new assay. Twenty commercially available NRL gloves were analyzed. Protein extraction was performed according to the international standard ASTM D-5712. Total protein content was measured with a modified Lowry method, NRL content with the CAP Inhibition Assay, the Beezhold ELISA Inhibition Assay, and an innovative ELISA with IgY-antibodies extracted from eggs of NRL-immunized hens (IgY Inhibition Assay). We found a high protein content in a range of 215.0-1304.7μg/g in 8 out of the 20 NRL gloves. Seven of the 20 gloves were powdered, four of them with a high protein content. In gloves with high protein content, the immunological tests detected congruently high levels of NRL allergen. We conclude that a high percentage of commercially available NRL gloves still represent a risk for NRL allergy, including asthma. The modified Lowry Method allows to infer on the latex allergen content.

High concentrations of natural rubber latex allergens in gloves used by laboratory health personnel in South Africa

Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported. Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a large laboratory service in South Africa. Methods. NRL gloves as well as non-latex gloves supplied by various suppliers that were used by the laboratory personnel during the period June 2009 - May 2010 were obtained from various suppliers on the vendor list. Proteins were extracted from the gloves and Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens were quantified using the FITkit assay. Results. Twenty NRL gloves from 13 different brands were analysed. Only four (20%) of the 20 NRL gloves analysed had a total allergen content <0.15 µg/g, the suggested threshold limit for low allergenicity for the sum of these four allergens. Conclusion. This study demonstrated that a very low proportion of gloves tested had a total allergen content below the threshold for low allergenicity.

Diagnostic value of the ISAC® allergy chip in detecting latex sensitizations

Latex allergy can be diagnosed by different test methods such as IgE quantification, Western blot, cellular antigen stimulation test (CAST), and in vivo methods [e.g. skin prick test (SPT)]. Phadia provides two modern methods using recombinant latex allergens: ImmunoCAP(®) and the Immuno Solid-phase Allergen Chip (ISAC(®)), which enables simultaneous determination of specific IgE against five latex allergens. We compared the diagnostic sensitivity of the ISAC(®) test kit and the conventional Hev b 5-spiked ImmunoCAP(®) latex extract. Forty sera were sampled from subjects with suspected natural rubber latex (NRL) allergy. These patients had positive SPT to NRL extract, positive NRL Western blots, and positive results in the CAST. All sera were analysed using the ISAC(®) and recombinant NRL ImmunoCAP(®) allergens and compared to the results of 20 negative control sera. Only 22 of the 40 subjects (55%) showed positivity to at least one latex allergen on the ISAC(®) (sensitivity ISAC(®) 55%). The sensitivity of the ImmunoCAP(®) latex extract was 70%. The most frequently detected sensitization was against Hev b 6.01 (n=12). When the serum samples were tested with all recombinant ImmunoCAP(®) allergens, three additional sensitizations against latex could be detected compared to the ISAC(®). Microarrays do offer many potential benefits such as elegant simultaneous determination of sensitizations against different NRL allergens with minimal amounts of serum. However, a negative NRL test result should be regarded with caution and at least be confirmed by other in vitro methods.

Component-resolved immunologic modifications, efficacy, and tolerance of latex sublingual immunotherapy in children

BackgroundAs the frequency of natural rubber latex (NRL) allergy has increased, attempts have been made to diminish exposure in high-risk patients. Despite some good results, complete NRL avoidance was not possible, so latex immunotherapy was developed. ObjectiveTo examine variations in immunologic parameters, clinical efficacy, and safety of NRL sublingual immunotherapy (SLIT). MethodsThis prospective, observational, open, case-control study included 23 patients (18 patients receiving NRL SLIT and 5 controls). Skin prick, conjunctival provocation, and in-use tests with NRL, specific IgE and specific IgG4 to NRL, specific IgE to recombinant NRL allergens, and basophil activation test (BAT) with whole latex, natural, and recombinant allergens were performed before immunotherapy (T0) and at 6 (T1) and 12 months (T2) of treatment. ResultsPatients were sensitized to Hev b 5, Hev b 6.01, and Hev b 6.02 proteins, optimal for SLIT. Changes in specific IgE were not significant. Increases in specific IgG4 between T1 and T2 were larger in the active group. BAT determinations showed significant decreases in recombinant Hev b 6.01 and natural Hev b 6.02 in the active group at T1 but not at T2. Both groups had new sensitizations at T1 but not at T2. The active group had significant increases in the response threshold in the in vivo tests at T1 and T2. Adverse effects were limited to local reactions. ConclusionNRL SLIT is effective and safe in children with latex allergy. Our results suggest that specific IgE determinations and BAT measurements to natural and recombinant latex allergens may allow obtaining an allergen-based diagnosis to help determine specific immunotherapy.

Allergy to natural rubber latex in asthma patients

Natural rubber latex (NRL) allergy has become an important occupational health problem in recent years. However, the prevalence of sensitization to NRL among allergic asthmatic patients is unknown. This study was undertaken evaluate the levels specific IgE in sera of 70 adult asthmatic patients (27 male and 43 female) with mild (32 patients) and moderate (38 patients) asthma, whose diagnosis was confirmed by case history, skin test results and RAST 20% of the asthmatics (14 patients) had latex-specific IgE in sera detected by Pharmacia UniCAP. Among the 14 latex sensitized asthmatics 6 patients had mild asthma and 8 had moderate asthma, 10 being male and 4 female. No latex-specific IgE was found in sera of 10 healthy donors. Among the 14 latex-sensitized asthmatics, 12 (86%) had sensitization to house dust; 13 (93%) sensitization to trees; 11 (79%) sensitization to grasses; 11 (79%) sensitization to weeds; 4 (29%) sensitization to cat/dog. There are no correlation between sensitivity to latex determined by latex specific IgE in sera and occupation of these asthma patients. 12 patients among the latex-sensitized asthmatics (86%0 had banana-specific IgE. 50 (72%) of the asthma patients had high levels of total IgE and all latex-sensitized asthmatics had high levels of total IgE. Using a one point RAST inhibition assay employing 10mg/ml of Greer latex extract 50% RAST inhibition was obtained, confirming specificity of the anti-latex IgE in these asthmatics. This study demonstrated a relatively high prevalence (20%) of in vitro reactivity to NRL allergens among patients with asthma. The source of sensitization to latex in these patients remains to be determined.

Genetic Predisposition to Natural Rubber Latex Allergy Differs Between Health Care Workers and High-Risk Patients

In health care workers, the natural rubber latex (NRL) allergy phenotype has been shown to be associated with promoter polymorphisms in interleukins 13 and 18 (IL13 and IL18) when compared with nonatopic controls. However, it is not known whether high-risk patient populations, such as those born with neural tube defects or genitourinary abnormalities, demonstrate a heightened propensity toward the same genetic/immunologic risk factors that have been reported for health care workers. In this study, we tested the hypothesis that single-nucleotide polymorphisms in genes encoding IL13 and IL18 occur at an increased frequency in NRL allergic patients with spina bifida (SB) or bladder exstrophy (BE). One hundred twenty subjects (40 SB, 40 BE, and 40 control) were screened using a clinical history questionnaire and NRL-specific immunoglobulin E (IgE) antibody measurements in the blood. Genomic DNA was extracted from peripheral blood lymphocytes and analyzed for single-nucleotide polymorphisms in candidate genes of interest. Univariate and multivariate analyses were performed to identify significant variables with significance defined as P < 0.05. Sensitization (IgE antibody positivity) to NRL allergens was associated with atopic history and number of prior operations and was prevented by the avoidance of NRL beginning at birth. However, unlike health care workers, the NRL allergy phenotype was not significantly associated with promoter polymorphisms in IL13 or IL18 when comparing NRL allergic SB and BE patients with nonsensitized patients and with atopic and nonatopic controls. In patients born with SB or BE, environmental factors seem to play a greater role in the development of NRL sensitization and overt allergic symptoms than the IL polymorphisms in IL13 and IL18 previously shown to be associated with NRL allergy in health care workers.

Allergenicity of latex rubber products used in South African dental schools.

Latex sensitisation is recognised as a health problem among health care workers (HCWs) using latex products. The aim of this study was to quantify specific latex allergens in latex devices used in South African academic dental schools. The current study also compared the total protein content and the levels of specific allergens in these products. Fourteen latex examination gloves (powdered and non-powdered) and five dental rubber dams, representing 6 brands, from five dental academic institutions were analysed for latex allergens and total protein. Total protein content was determined using the BioRad DC protein assay kit and natural rubber allergen levels using a capture enyme-linked immunosorbent assay (ELISA) specific for Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02. Hev b 6.02 was found in higher concentrations than other natural rubber latex (NRL) allergens in the products analysed. Hev b 5 content ranged from 0 to 9.2 microg/g and Hev b 6.02 from 0.09 to 61.5 microg/g of sample. Hev b 1 levels were below the detection limit (DL) for 79% of the samples (15/19). Dental dams showed higher allergen levels (median 80.91 microg/g) than latex gloves (median 11.34 microg/g). Powdered rubber samples also showed higher allergen levels (median 40.54 microg/g) than non-powdered samples (median 5.31 microg/g). A statistically significant correlation was observed between total protein and total allergen (r=0.74, p<0.001) concentrations. NRL allergen concentrations differ significantly by product and brand. This study has demonstrated that NRL allergens in latex-containing products used in South African dental institutions are present at sufficiently high levels to pose an allergic health risk.

The importance of nasal provocation test in the diagnosis of natural rubber latex allergy

Most studies regarding natural rubber latex (NRL) allergy have concentrated on the prevalence using skin prick test (SPT) and specific IgE assay. The objective of this study is to examine the target organ (skin, nasal mucosa) responses in patients with positive SPT to NRL using the nasal provocation test (NPT) and glove use test (GUT). Four thousand four hundred and twenty patients presented to our polyclinic between July 2003 and January 2007 were evaluated. One thousand six hundred and ninety-nine patients had positive SPT to one or more allergens (NRL and other inhaler allergens). Twenty-nine patients with positive SPT to NRL comprised the NRL sensitive group (group 1). Thirty-five randomized patients with positive SPT to an inhaler allergen other than NRL and negative NRL-specific IgE comprised atopic control group (group 2). Thirty healthy individuals who had no allergic diseases and had negative SPT and NRL-specific IgE comprised the healthy control group (group 3). The lowest NRL allergen concentration leading to NPT positiveness was 0.05 microg/mL. NPT was negative in groups 2 and 3. NPT was found to have a sensitivity of 96%, specificity of 100%, negative predictive value of 98% and positive predictive value of 100%. GUT was found to have a sensitivity of 81%, specificity of 90%, negative predictive value of 75% and positive predictive value of 93%. Nasal provocation test was successfully used for the first time in the diagnosis of NRL allergy. NPT is a more sensitive method as compared to GUT.

Hev b 6.02 Is the Most Important Allergen in Health Care Workers Sensitized Occupationally by Natural Rubber Latex Gloves

Natural rubber latex (NRL) allergy is a common occupational disease in health care workers (HCW). However, few reports have compared the major allergen of HCWs to those in gloves that are routinely used in the hospital. The aim of this study was to evaluate the major NRL allergens in gloves used by HCWs. We studied 20 HCWs who were suspected to have latex allergy (LA). We performed a skin prick test (SPT) using NRL allergens. Serological testing was performed using the ImmunoCAPTM. The total amount of protein and the antigenic protein concentrations extracted from NRL gloves were measured. Four different types of FITkitTM were used to measure the concentrations of Hev b 1, 3, 5, and 6.02 in the gloves. A SPT using NRL extract identified 14 cases with positive reactions. The sensitivity and specificity of the SPT scores to the NRL glove extract were 100%. The sensitivity of latex specific IgE was 100% but the specificity was 14.2%. The sensitivity and specificity of rHev b 6.02 specific IgE were 100% in the LA group. The total amounts of protein from the medical gloves for surgery and examination were 265 microg/g and 95 microg/g, respectively. The antigenic protein concentrations in the gloves were 24.9 microg/g and 1.0 microg/g, respectively. The total amounts of the specific four allergens in the NRL gloves were 2.18 microg/g and 0.45 microg/g, respectively. We concluded that the main allergen of HCWs who have been sensitized occupationally by NRL gloves was Hev b 6.02.