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Interventions of latex allergen inhaled by health care workers through use of breathing masks or non-powdered gloves
J ALLERGY CLIN IMMUNOL VOLUME 109, NUMBER 1
Abstracts
783 Diagnostic Sensitivity of Puncture Skin Testing (PST)With Isolated Native and Recombinant Proteins From Hevea Brasilien-
sis (Hev b) for the Diagnosis of Latex Hypersensitivity in Healthcare Workers (HCWs)
Raymond Biagini*, David I Bernstein§, Ravi Karnani§, Karen Murphy§, Cheryl Bernstein§, Brian Berendts§, Jonathan A Bernstein§, I Leonard Bernstein§, Carol Abbott§, Hoong-Yeet Yeang~, Siti Arija~, Robert G Hamilton~ *NIOSH, Cincinnati, OH §University of Cincinnati, Cincinnati, OH ¥Rubber Research Institute of Malaysia, Kuala Lumpur, Malaysia ~Johns Hopkins University School of Medicine, Baltimore, MD BACKGROUND: Eleven natural rubber latex (NRL) Hev b allergens (Hev b 1 to Hey b 11) have been cloned and sequenced. Skin testing has been performed with recombinant forms of many of these Hev b allergens (Int. Arch. Allergy Immunol. 121:292-9, 2000) in latex sensitive individuals. However, skin testing of HCWs with native forms of the Hey b allergens has not been previously reported. OBJECTIVE: The aim of the present study was to evaluate puncture skin test (PST) reactivity to Hey b allergens 1, 2, 3, 4, 6, 7b, and 7c purified from non-ammoniated latex (NAL) and to recombinant Hey b 5, in HCWs. METHODS: Endpoint percutaneous threshold concentrations (EPC) were determined in 62 NAL sensitized atopic HCWs with latex allergy and in 20 atopic NAL negative HCWs without histories of latex allergy. Subjects were evaluated with 7 increasing 10-fold concentrations of NAL (0.000001 to 1 mg/ml of NRL protein) and all 8 individual Hey b proteins (0.00005 to 50 p.g protein/ml). RESULTS: Of the 62 latex allergic subjects, 5 (8.1%) had no skin test reactivity to any of the Hey b 1-7b/c. Because these 5 subjects had a positive PST to NAL, with endpoint titers from 0.000l to 0.01 mg/ml, at least one other potent Hey b allergen is critical to eliciting skin reactions in these subjects. The remaining 57 subjects displayed heterogeneous IgE reactivity to the Hey b allergens. Frequency of IgE reactivity to the 8 Hey b allergens was: 23% (Hey bl), 63% (Hev b2), 24% (Hev b3), 39% (Hev b4), 65% (Hev b5), 63% (Hev b6), 63% (Hev b7b) and 45% (Hev b7c). The EPCs for NAL and the Hev b proteins were significantly associated (P<0.05) for Hev b 1, 2, 4, 5, 6 and 7c with the largest correlation coefficient (0.482) being demonstrated for Hev b5. Importantly, 50 of the 62 individuals (81%) had simultaneous positive PSTs to Hev b 5, 6, and/or 7b, while 57 were positive to Hev b 2, 3, 4, 5, 6 and/or 7b (sensitivity=92%). Only 1 of 20 NAL negative non-allergic HCWs was PST positive to Hev b antigens (Hev 7b at 50 ~g/ml), indicating that Hev b PST reactivity was specific for HCWs with latex allergy (specificity=95%). The diagnostic sensitivity (92%) observed with PST using the Hev b protein combination 2, 3, 4, 5, 6 and/or 7b was significantly greater (chi square, P<0.001) than those observed when IgE was measured in serum from the same subjects using CAP (50%), AlaSTAT (67%) or EIA with purified Hev b allergens. CONCLUSION: While PSTs with purified Hev b 1-7b/c allergens are able to identify most latex allergic HCWs, diagnostic sensitivity and specificity achieved by PST with a combination of these allergens still does not match the performance of PST using NAL alone.
784
Binding Propensity of NRL Proteins to Glove Powder
Anne D Lucas, Vesna J Tomazic-Jezic Food & Drug Administration, Rockville, MD Cornstarch used as a donning powder on natural rubber latex (NRL) gloves adsorbs NRL proteins. During glove use, powder-bound proteins are aerosolized, causing allergic reactions in NRL sensitized individuals. The propensity of NRL proteins binding to glove powder relative to a total amount of protein on glove and the possible selectivity of binding has not been studied due to the difficulty of identifying powder-bound proteins.
S257
Using the ELISA Inhibition assay for NRL proteins (ASTM standard D6499), we have investigated possible modifications of the protocol in order to include measurement of protein amount bound to glove powder, as well as water-extractable glove proteins. The possible interference of the starch itself was evaluated by adding clean cornstarch to the assay. No interference was observed with powder concentrations below 5 mg/ml. We analyzed 21 extracts of powdered surgical and examination gloves before and after removal of particulate component. Comparison of NRL glove extracts with and without the comstarch powder fraction, indicated significant variations in the ratios of powder-bound protein and corresponding waterextractable protein. The ratios did not appear to correlate with either the total protein on the glove, the glove weight or the powder amount. However, when clean cross-linked cornstarch was exposed to NRL proteins, binding was proportional to the protein concentration in the suspension. The percentage of protein binding to starch was decreasing with the increasing concentration of protein, indicating a saturation point. These data indicate that the amount of protein that binds to glove powder does not depend only on the starting protein levels in NRL. Most likely, other physical or chemical factors introduced during manufacturing process, as well as the properties of the donning powder itself, may influence protein binding. We furthermore demonstrated that the ELISA Inhibition assay could be successfully modified for quantitation of proteins adsorbed on the glove powder, together with water-extractable proteins.
785
Interventions of Latex Allergen Inhaled by Health Care Workers Through Use of Breathing Masks or Non-Powdered Gloves
Teresa Z Mitakakis*, Euan R Tovey§, Deborah Yates~, Timothy John O'MearaC, Brett Toelle~, Anthony Johnson,, Michael Sutherland~,, Robyn E O'Hehir~, Guy Marks¥ *Cooperative Research Center for Asthma, Camperdown, NSW, Australia §University of Sydney, Sydney, NSW, Australia ¥C0operative Research Center for Asthma, Sydney, NSW, Australia ~Elnstitute of Respiratory Medicine, Sydney, NSW, Australia ~Monash University, Sydney, NSW, Australia Allergy to powdered latex gloves is a well characterised phenomenon, particularly amongst health care workers. Despite this, many hospitals still provide staff with powdered latex gloves. Aims: (1) To measure the dose of allergenic latex particles inhaled by hospital health care workers wearing standard latex gloves, provided by the hospital, while performing routine activities in a bronchoscopy suite. (2) To measure the extent to which exposure was reduced by the use of protective masks or by replacing powdered gloves with non-powered latex gloves. 20 health care workers wore nasal air samplers (NAS) and IOM filter pumps (IOM) on the lapel for 4 x 20-minute sampling periods. Each subject wore powdered gloves, non-powdered gloves and no gloves during three of the sampling periods. In the fourth sampiing period, each subject applied a face-mask while wearing the powdered gloves. Half the subjects used an aerosol barrier mask and the others wore a particulate mask (N95). All samples were stained for particles bearing Hev b 5 allergen by the Halogen assay. Haloed particles were counted and conditions were compared by paired sample T-tests. All subjects inhaled Hev b 5 bearing particles in all sampling periods. On average, the IOM sampler collected particles at 70% of the rate of the NAS. The number of particles inhaled while wearing standard, powdered gloves was 23.8 fold higher than when not wearing gloves and 9.7 fold higher than when wearing non-powdered latex gloves (P < .0001). The effectiveness of the masks was assessed by comparing the NAS to IOM ratio with and without a mask, to correct for between-sampling period variation in actual exposure. Wearing a mask reduced the NAS to IOM ratio by 7.5 fold (P = 0.01). There was no significant difference between the two types of masks examined (P = 0.2). The use of non-powdered gloves is the most effective method of reducing occupational exposure to latex arising from gloves. However, secondary protection using aerosol or particulate masks is an acceptable alternative.
Abstracts
783 Diagnostic Sensitivity of Puncture Skin Testing (PST)With Isolated Native and Recombinant Proteins From Hevea Brasilien-
sis (Hev b) for the Diagnosis of Latex Hypersensitivity in Healthcare Workers (HCWs)
Raymond Biagini*, David I Bernstein§, Ravi Karnani§, Karen Murphy§, Cheryl Bernstein§, Brian Berendts§, Jonathan A Bernstein§, I Leonard Bernstein§, Carol Abbott§, Hoong-Yeet Yeang~, Siti Arija~, Robert G Hamilton~ *NIOSH, Cincinnati, OH §University of Cincinnati, Cincinnati, OH ¥Rubber Research Institute of Malaysia, Kuala Lumpur, Malaysia ~Johns Hopkins University School of Medicine, Baltimore, MD BACKGROUND: Eleven natural rubber latex (NRL) Hev b allergens (Hev b 1 to Hey b 11) have been cloned and sequenced. Skin testing has been performed with recombinant forms of many of these Hev b allergens (Int. Arch. Allergy Immunol. 121:292-9, 2000) in latex sensitive individuals. However, skin testing of HCWs with native forms of the Hey b allergens has not been previously reported. OBJECTIVE: The aim of the present study was to evaluate puncture skin test (PST) reactivity to Hey b allergens 1, 2, 3, 4, 6, 7b, and 7c purified from non-ammoniated latex (NAL) and to recombinant Hey b 5, in HCWs. METHODS: Endpoint percutaneous threshold concentrations (EPC) were determined in 62 NAL sensitized atopic HCWs with latex allergy and in 20 atopic NAL negative HCWs without histories of latex allergy. Subjects were evaluated with 7 increasing 10-fold concentrations of NAL (0.000001 to 1 mg/ml of NRL protein) and all 8 individual Hey b proteins (0.00005 to 50 p.g protein/ml). RESULTS: Of the 62 latex allergic subjects, 5 (8.1%) had no skin test reactivity to any of the Hey b 1-7b/c. Because these 5 subjects had a positive PST to NAL, with endpoint titers from 0.000l to 0.01 mg/ml, at least one other potent Hey b allergen is critical to eliciting skin reactions in these subjects. The remaining 57 subjects displayed heterogeneous IgE reactivity to the Hey b allergens. Frequency of IgE reactivity to the 8 Hey b allergens was: 23% (Hey bl), 63% (Hev b2), 24% (Hev b3), 39% (Hev b4), 65% (Hev b5), 63% (Hev b6), 63% (Hev b7b) and 45% (Hev b7c). The EPCs for NAL and the Hev b proteins were significantly associated (P<0.05) for Hev b 1, 2, 4, 5, 6 and 7c with the largest correlation coefficient (0.482) being demonstrated for Hev b5. Importantly, 50 of the 62 individuals (81%) had simultaneous positive PSTs to Hev b 5, 6, and/or 7b, while 57 were positive to Hev b 2, 3, 4, 5, 6 and/or 7b (sensitivity=92%). Only 1 of 20 NAL negative non-allergic HCWs was PST positive to Hev b antigens (Hev 7b at 50 ~g/ml), indicating that Hev b PST reactivity was specific for HCWs with latex allergy (specificity=95%). The diagnostic sensitivity (92%) observed with PST using the Hev b protein combination 2, 3, 4, 5, 6 and/or 7b was significantly greater (chi square, P<0.001) than those observed when IgE was measured in serum from the same subjects using CAP (50%), AlaSTAT (67%) or EIA with purified Hev b allergens. CONCLUSION: While PSTs with purified Hev b 1-7b/c allergens are able to identify most latex allergic HCWs, diagnostic sensitivity and specificity achieved by PST with a combination of these allergens still does not match the performance of PST using NAL alone.
784
Binding Propensity of NRL Proteins to Glove Powder
Anne D Lucas, Vesna J Tomazic-Jezic Food & Drug Administration, Rockville, MD Cornstarch used as a donning powder on natural rubber latex (NRL) gloves adsorbs NRL proteins. During glove use, powder-bound proteins are aerosolized, causing allergic reactions in NRL sensitized individuals. The propensity of NRL proteins binding to glove powder relative to a total amount of protein on glove and the possible selectivity of binding has not been studied due to the difficulty of identifying powder-bound proteins.
S257
Using the ELISA Inhibition assay for NRL proteins (ASTM standard D6499), we have investigated possible modifications of the protocol in order to include measurement of protein amount bound to glove powder, as well as water-extractable glove proteins. The possible interference of the starch itself was evaluated by adding clean cornstarch to the assay. No interference was observed with powder concentrations below 5 mg/ml. We analyzed 21 extracts of powdered surgical and examination gloves before and after removal of particulate component. Comparison of NRL glove extracts with and without the comstarch powder fraction, indicated significant variations in the ratios of powder-bound protein and corresponding waterextractable protein. The ratios did not appear to correlate with either the total protein on the glove, the glove weight or the powder amount. However, when clean cross-linked cornstarch was exposed to NRL proteins, binding was proportional to the protein concentration in the suspension. The percentage of protein binding to starch was decreasing with the increasing concentration of protein, indicating a saturation point. These data indicate that the amount of protein that binds to glove powder does not depend only on the starting protein levels in NRL. Most likely, other physical or chemical factors introduced during manufacturing process, as well as the properties of the donning powder itself, may influence protein binding. We furthermore demonstrated that the ELISA Inhibition assay could be successfully modified for quantitation of proteins adsorbed on the glove powder, together with water-extractable proteins.
785
Interventions of Latex Allergen Inhaled by Health Care Workers Through Use of Breathing Masks or Non-Powdered Gloves
Teresa Z Mitakakis*, Euan R Tovey§, Deborah Yates~, Timothy John O'MearaC, Brett Toelle~, Anthony Johnson,, Michael Sutherland~,, Robyn E O'Hehir~, Guy Marks¥ *Cooperative Research Center for Asthma, Camperdown, NSW, Australia §University of Sydney, Sydney, NSW, Australia ¥C0operative Research Center for Asthma, Sydney, NSW, Australia ~Elnstitute of Respiratory Medicine, Sydney, NSW, Australia ~Monash University, Sydney, NSW, Australia Allergy to powdered latex gloves is a well characterised phenomenon, particularly amongst health care workers. Despite this, many hospitals still provide staff with powdered latex gloves. Aims: (1) To measure the dose of allergenic latex particles inhaled by hospital health care workers wearing standard latex gloves, provided by the hospital, while performing routine activities in a bronchoscopy suite. (2) To measure the extent to which exposure was reduced by the use of protective masks or by replacing powdered gloves with non-powered latex gloves. 20 health care workers wore nasal air samplers (NAS) and IOM filter pumps (IOM) on the lapel for 4 x 20-minute sampling periods. Each subject wore powdered gloves, non-powdered gloves and no gloves during three of the sampling periods. In the fourth sampiing period, each subject applied a face-mask while wearing the powdered gloves. Half the subjects used an aerosol barrier mask and the others wore a particulate mask (N95). All samples were stained for particles bearing Hev b 5 allergen by the Halogen assay. Haloed particles were counted and conditions were compared by paired sample T-tests. All subjects inhaled Hev b 5 bearing particles in all sampling periods. On average, the IOM sampler collected particles at 70% of the rate of the NAS. The number of particles inhaled while wearing standard, powdered gloves was 23.8 fold higher than when not wearing gloves and 9.7 fold higher than when wearing non-powdered latex gloves (P < .0001). The effectiveness of the masks was assessed by comparing the NAS to IOM ratio with and without a mask, to correct for between-sampling period variation in actual exposure. Wearing a mask reduced the NAS to IOM ratio by 7.5 fold (P = 0.01). There was no significant difference between the two types of masks examined (P = 0.2). The use of non-powdered gloves is the most effective method of reducing occupational exposure to latex arising from gloves. However, secondary protection using aerosol or particulate masks is an acceptable alternative.