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Background: As 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., Objective: To examine variations in immunologic parameters, clinical efficacy, and safety of NRL sublingual immunotherapy (SLIT)., Methods: This 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., Results: Patients 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., Conclusion: NRL 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., (Copyright © 2012 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

It is a matter of debate whether single nucleotide polymorphisms (SNP) in the promoter region of interleukin (IL)-13, an IgE regulator, and IL-18, an inducer of immune responses, modulating the respective protein expression, are accompanied by an increased risk of atopy, allergic asthma, and total IgE levels. The suspected associations were noted in health care workers (HCW) with and without latex allergy. IL-13 (-1055C>T) and three IL-18 (-656T>G, -607C>A, -137G>C) SNP were studied in 523 HCW with natural rubber latex (NRL) exposure and diagnosis in the late 1990s. Three hundred and thirty-four HCW displayed NRL sensitization and allergic symptoms, 93 with latex-allergic asthma, and 189 HCW with neither symptoms nor NRL sensitization. SNP analyses were performed by real-time polymerase chain reaction (PCR) using newly developed LightCycler assays. Analysis of IL-13 -1055C>T by analysis of variance (ANOVA) revealed significantly elevated total IgE levels in HCW carrying the CT or TT variant compared with the CC variant. None of the studied SNP showed an association with NRL-specific IgE. The IL-18 variants -656GG and -607CC displayed 99.5% linkage disequilibrium. Frequencies of alleles -656GG and -607CC were elevated in HCW with NRL asthma (48.4%) compared with HCW without symptoms (37.6%). In contrast, IL-18 -137G>C variants displayed an overall homogenous distribution. The association between the IL-13 -1055T allele and elevated total IgE levels confirms the role of a genetic background for total IgE regulation. The studied IL-18 SNP demonstrated no significant association with the clinical outcome, total IgE, or specific IgE in HCW with natural rubber latex allergy.

Objectives: Powdered latex gloves or latex gloves with high allergen content are forbidden in Germany since 1998. It was the aim of this study to test the hypothesis that nationwide preventive measures enable health care workers with latex allergy to work without health risks about 10 years afterwards., Methods: Ninety-one health care workers who had been reported to the accident insurance between 1996 and 2004 for occupational latex allergy were examined in 2007. The survey included a questionnaire, a physical examination, spirometry, methacholine testing, skin prick testing and serum IgE measurements to latex and environmental allergens., Results: Recent work-related possibly allergic symptoms were reported by 32 subjects (35%), among them 18 subjects (20%) with symptoms of the eyes, nose or airways. Current sensitization to latex was detected in 61 subjects (67%), and 60 subjects (66%) were atopic. Eleven subjects (12%) showed mild airway obstruction, and 27 subjects (30%) were considered hyperresponsive to methacholine. Whereas overall recent symptoms of the eyes, nose or airways were associated with current latex sensitization (OR 4.5; 95% CI 1.3-16.2), this was not the case for objective outcome parameters (spirometry, bronchial hyperresponsiveness)., Conclusions: Although most subjects had only mild disease, ongoing work-related symptoms of the eyes, nose or airways in a substantial number of subjects with latex allergy suggest the need for further secondary preventive measures in German healthcare.

Background: Component-resolved diagnosis using microarray technology has recently been introduced in clinical allergology, but its applicability in patients with natural rubber latex (NRL) allergy has not been investigated., Objectives: To evaluate the utility of microarray-based immunoglobulin (Ig) E detection in the diagnostic workup of NRL allergy and to compare this new diagnostic tool with established methods of NRL-specific IgE detection., Methods: We investigated 52 adults with immediate-type NRL allergy and 50 control patients. Determination of specific serum IgE against 8 recombinant Hevea brasiliensis allergen components was performed using a customized allergen microarray and a conventional fluorescence enzyme immunoassay (FEIA)., Results: The panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant NRL proteins. NRL-specific IgE recognition patterns and sensitization rates determined by microarray analysis were similar to those obtained by conventional FEIA. The diagnostic sensitivity rates of combined single-component data were not significantly different for the respective recombinant test system, whereas the sensitivity level of extract-based FEIA analysis was markedly higher., Conclusion: The current study provides evidence that microarrays of recombinant NRL allergen components are a suitable new tool for the diagnosis of NRL-specific sensitization.They show performance characteristics comparable to those of current diagnostic tests and could be indicated in small children in whom only limited blood volumes are obtainable. Further large-scale studies in unselected patient populations and in high-risk groups are warranted before the microarray can be introduced into routine management of patients with NRL allergy.

Objective: The quality of life (QOL) and work ability of health care workers allergic to natural rubber latex (NRL) were assessed after implementation of regulations on powder-free NRL gloves in Germany., Methods: 196 HCW with reported NRL allergy answered a questionnaire (response rate 58%) containing the Work Ability Index (WAI), Mini Asthma Quality of Life Questionnaire (MiniAQLQ), and Dermatology Life Quality Index (DLQI)., Results: 63.2% still had NRL-related symptoms during the last 6 month. However on a scale from 0 to 10, the intensity of NRL-related symptoms decreased from 8.5 before to 2.3 after implementation of regulations on powder-free NRL gloves. A higher number of subjects were able to avoid NRL in the private than in the work environment (85% vs. 61%). NRL-related symptoms decreased and WAI increased with successful avoidance of NRL at workplace (b = 0.23, p = 0.003). QOL was only little affected by NRL allergy (mean: MiniAQLQ = 6.0; DLQI = 4.1)., Conclusions: Although there was improvement after implementation of powder-free NRL gloves, there is still a considerable number of HCW with NRL-related symptoms. Further investigations on latex avoidance and the cause of persisiting allergic symptoms in HCW with NRL allergy are therefore needed.

Background: Characterized native and recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergens are available to assess patient allergen sensitization profiles., Objective: Quantification of individual IgE responses to the spectrum of documented NRL allergens and evaluation of cross-reactive carbohydrate determinants (CCDs) for more definitive diagnosis., Methods: Sera of 104 healthcare workers (HCW; 51 German, 21 Portuguese, 32 American), 31 spina bifida patients (SB; 11 German, 20 Portuguese) and 10 Portuguese with multiple surgeries (MS) were analysed for allergen-specific IgE antibody (sIgE) to NRL, single Hev b allergens and CCDs with ImmunoCAP technology., Results: In all patient groups rHev b 5-sIgE concentrations were the most pronounced. Hev b 2, 5, 6.01 and 13 were identified as the major allergens in HCW and combined with Hev b 1 and Hev b 3 in SB. In MS Hev b 1 displayed an intermediate relevance. Different sIgE antibody levels to native Hevea brasiliensis (nHev b) 2 and rHev b 6.01 allowed discrimination of SB with clinical relevant latex allergy vs. those with latex sensitization. Sensitization profiles of German, Portuguese and American patients were equivalent. rHev b 5, 6.01 and nHev b 13 combined detected 100% of the latex-allergic HCW and 80.1% of the SB. Only 8.3% of the sera showed sIgE response to CCDs., Conclusions: Hev b 1, 2, 5, 6.01 and 13 were identified as the major Hev b allergens and they should be present in standardized latex extracts and in vitro allergosorbents. CCDs are only of minor relevance in patients with clinical relevant latex allergy. Component-resolved diagnostic analyses for latex allergy set the stage for an allergen-directed immunotherapy strategy.

Background: Chestnut and natural rubber latex (NRL) allergy are often associated in the latex-fruit syndrome., Aim of the Study: To establish whether the concurrent NRL and chestnut IgE antibody reactivity are the results of co-sensitization or cross-reactivity., Methods: Sera from 19 patients with chestnut- and NRL-specific IgE were selected and tested for reactivity with recombinant (r) latex allergens. Cross-reactivity was explored by IgE-inhibition experiments using chestnut or NRL allergens as solid phase on ImmunoCAP., Results: IgE-antibodies were detected to rHev b 6.01 (prohevein) in 58% of the sera, to rHev b 5 in 32%, to rHev b 12 in four of 13 sera, to rHev b 7.02 and rHev b 11 in four, and to rHev b 1 in two of 19 sera. rHev b 8-IgE antibodies were found in nine sera (47%), whereas six displayed mono-sensitization to rHev b 8 with regard to our test panel. Three of 16 sera showed IgE to cross-reactive carbohydrate determinants. In most sera recognizing rHev b 5 and/or rHev b 6.01 as major allergens the IgE-reactivity to NRL remained unaffected by chestnut extract and chestnut-IgE remained unaffected by NRL extract. Conversely, in sera with rHev b 8 as dominant allergen IgE-binding to NRL was nearly completely inhibited by chestnut and vice versa. IgE-binding to rHev b 8 was abolished by chestnut extract., Conclusions: Although patients have concomitant IgE antibody reactivity to chestnut and NRL, cross-reactivity could be demonstrated mainly in those patients with IgE to Hev b 8 (profilin) from NRL.

Background: Occupational allergy to latex is generally reported from occupational groups such as health care workers; however, few reports derive from other occupational settings., Methods: Two male subjects working as loom tuners in a textile manufacturing plant developed severe allergic reactions during the cutting and weaving of elastic bands, initially not suspected to contain latex constituents. Clinical evaluation and lung function tests were supplemented by skin prick testing, specific IgE evaluation and basophil activation assays with extracted elastic bands., Results: Both workers presented with rhinitis, episodes of tight chest and itchy eyes. Initial spirometry was normal with no significant reversibility; however, a histamine challenge test was positive in one worker. Skin prick testing to a battery of common inhalant allergens was negative; however, raised IgE levels were detected to latex using ImmunoCAP. On further testing, the specific IgE response was directed mainly to the major latex allergens rHev b 5, rHev b 6.01, rHev b 6.02 and nHev b 13. Basophils of the two workers, but not the unaffected control subjects, were strongly activated by extracts of the elastic and the cutting dust material., Conclusions: Workers are at high risk of becoming sensitised to latex allergens when exposed to excessive dust produced by loom tuning machines. Latex sensitisation should therefore be considered in workers developing unexplained work-related allergic reactions (including asthma) associated with unlabelled materials in the textile industry.

Background: Hevea brasiliensis latex serum is commonly used as the in vivo and in vitro reference antigen for latex allergy diagnosis as it contains the full complement of latex allergens., Objective: This study quantifies the concentrations of the significant allergens in latex serum and examines its suitability as an antigen source in latex allergy diagnosis and immunotherapy., Methods: The serum phase was extracted from centrifuged latex that was repeatedly freeze-thawed or glycerinated. Quantitation of latex allergens was performed by two-site immunoenzymetric assays. The abundance of RNA transcripts of the latex allergens was estimated from the number of their clones in an Expressed Sequence Tags library., Results: The latex allergens, Hev b 1, 2, 3, 4, 5, 6, 7 and 13, were detected in freeze-thawed and glycerinated latex serum at levels ranging from 75 (Hev b 6) to 0.06 nmol/mg total proteins (Hev b 4). Hev b 6 content in the latex was up to a thousand times higher than the other seven latex allergens, depending on source and/or preparation procedure. Allergen concentration was reflected in the abundance of mRNA transcripts. When used as the antigen, latex serum may bias the outcome of latex allergy diagnostic tests towards sensitization to Hev b 6. Tests that make use of latex serum may fail to detect latex-specific IgE reactivity in subjects who are sensitized only to allergens that are present at low concentrations., Conclusion: Latex allergy diagnostics and immunotherapy that use whole latex serum as the antigen source may not be optimal because of the marked imbalance of its constituent allergens.

There are no documented studies that describe natural rubber latex (NRL) sensitization in children with a history of surgical intervention but without any congenital malformation (urogenital anomalies, spina bifida, etc.), although some authors have studied NRL allergy in children without a history of surgical intervention. The aim of this work was to evaluate the sensitization profile to single NRL allergens in children without spina bifida and without repeated surgical interventions, by using different recombinant and natural latex allergens in two analytical techniques: specific serum immunoglobulin E (IgE) quantification and flow cytometry determination of activated basophils expressing CD63, after stimulating cells from patients with NRL allergens. A total of 23 patients and 10 healthy children were selected. Conjunctival and in-use NRL provocation tests were carried out, as well as specific IgE determination in all patients' and controls' sera with the recombinant NRL allergens: rHev b 1, rHev b 2, rHev b 3, rHev b 5, rHev b 6.01, rHev b 6.02, rHev b 8, rHev b 9 and rHev b 11 and with NRL (k82) using appropriate ImmunoCAPs. The Basophil Activation Test (BAT) was performed with whole latex extract and with the recombinant allergens rHev b 5 and rHev b 6.01, as well as with the natural allergen Hev b 6.02. The sensitivity and the specificity of NRL-specific IgE (k82) were 100%. Positive IgE responses to rHev b 5 were found in sera of 10 children, to rHev b 6.01 in 16 and for rHev b 6.02 in 15 children's sera. Specific IgE to rHev b 8 was found in four sera of the children. We only found significant differences in sensitization to rHev b 5 in children with two or more surgical interventions compared with the non-intervened group or those with only one intervention. Specific IgE in sera of children with latex-fruit syndrome recognized rHev b 6.02, but not to rHev b 11. The patients sensitized to Hev b 8, Hev b 9 and/or Hev b 11 were atopic. The four patients presenting a positive response to the NRL profilin Hev b 8 were allergic to pollen. The BAT against whole NRL extract was positive in 22 of 23 children; against rHev b 5 in 14 of the patients studied; against rHev b 6.01 in seven cases and against nHev b 6.02 in 19 children. In all the control subjects, the results using this technique were negative. If combined rHev b 5, rHev b 6.01 and nHev b 6.02 together, BAT could detect 20 of the 23 children with latex allergy. The combined use of ImmunoCAP with all the recombinant NRL allergens and BAT with rHev b 5, rHev b 6.01 and nHev b 6.02, enabled the identification of NRL allergy in 22 of 23 patients. There is a positive and significant correlation between sensitization to Hev b 5 and the number of interventions. BAT and allergen-specific IgE determination could be used as first-line in vitro diagnostic tests in patients with NRL allergy.

Background: New IgE sensitizations to proteins in allergen extracts have been shown to occur during allergen-specific immunotherapy (IT)., Methods: Twenty-four healthcare workers (HCWs) -- patients included in a latex IT study -- were analysed, 16 in active treatment and eight in placebo. Sera were obtained at baseline and after 6 months of IT and analysed with immunoblotting and CAP System with eight single recombinant latex allergens (rHev b 1, 3, 5, 6.01, 8, 9, 10, 11, and a mix of rHev b1, 5, 6.01 and 8)., Results: After IT with latex, three patients in the active treatment group had new IgE sensitizations, one to Hev b 5, one to Hev b 11 and another to Hev b 6.01. No other significant variation in mean of specific IgE to latex or recombinant allergens were observed in patients who received placebo or active treatment. A significant (P = 0.012) negative correlation (-0.72) was observed between maximal tolerated dose and specific IgE to Hev b 6.01 at baseline. After IT, immunoblot analysis demonstrated a significant increase in IgE binding in a band of approximately 22 kDa (P = 0.032) that may correspond to Hev b 6.01. New or more intense bands appeared in seven patients of the active group, while in three subjects a reduction was observed., Conclusions: Hev b 6.01 seems to be the most relevant latex allergen in HCWs. New or more intense IgE binding to latex allergenic components occurs during latex immunotherapy. However, the levels of specific IgE against these new components are low and do not seem to have clinical relevance.

Single recombinant latex allergens permit the study of the pattern of sensitization to individual allergens. We aimed to quantify the IgE-response to individual latex allergens in children sensitized to latex. The study group included 31 latex-sensitized children: 26 operated at least twice, 20 of them with spina bifida; two children with one operation and three atopic non-operated children. IgE antibodies to rHev b 1, rHev b 3, rHev b 5, rHev b 6.01, rHev b 7.02 and rHev b 8, coupled to ImmunoCAPs, were measured in each serum. IgE responses to rHev b 1, rHev b 5 and rHev b 6.01 were found in 17 children each, and their mean +/- s.d. levels were 5 +/- 7.4, 16.8 +/- 14 and 10 +/- 18 kU/l, respectively. IgE responses to rHev b 3 (4 +/- 5.4 kU/l) were found in eight children. Two children had IgE to rHev b 7 (1.7 and 3.2 kU/l), and none to rHev b 8. Four sera were negative to all tested recombinant allergens. We divided the patients in three groups: sensitized only to rHev b 1, sensitized only to rHev b 5 and/or rHev b 6.01, and sensitized to both rHev b 1 and to rHev b 5 and/or rHev b 6.01. The three groups had the same profile of clinical features. Hev b 5 induces the quantitatively higher IgE responses in children with multiple surgeries sensitized to latex. Responses to Hev b 6.01 equal those of Hev b 1.

Objectives: There is insufficient data on the prevalence of latex allergy in the general population in Poland. The aim of the study was to evaluate natural rubber latex (NRL) sensitization and its risk factors among Polish blood donors., Materials and Methods: The study group comprised 1000 consecutive blood donors attending the Regional Centre for Transfusion Medicine. Total IgE and allergen specific IgE to NRL (asNRL-IgE) were assayed using the EIA (enzyme immunoassay) test. In the subjects with asNRL-IgE equal to or above Class II further surveys were performed: questionnaire, skin prick tests (SPT) to common allergens, NRL and food allergens cross reactive to NRL, asNRL-IgE with FDA (Food and Drug Administration) approved FEIA (fluorescent enzyme immunoassay) test and antigen profile of asNRL-IgE., Results: asNRL-IgE (EIA) was observed in 17.9% of blood donors. Only 10% of positive results equal to or above Class II were confirmed with the FEIA test. The positive FEIA results were confirmed with SPT to NRL in 60% and the negative FEIA results in 5.4% of cases. The specific IgE to Hev b 3, 5, 6 and 13 were observed in the subjects with occupational exposure to NRL. The highest concentration of Hev b 8 was observed in the subjects not symptomatic to NRL with positive SPT to grass and tree pollens., Conclusion: The EIA test showed the high prevalence of antigen specific IgE to NRL among Polish blood donors. There was low concordance between EIA and FEIA tests. Therefore, the EIA test should be used only for screening purposes along with the establishment of sensitivity and specificity of the method. Elevated total IgE level, active tobacco smoking, and history of atopic disease symptoms were revealed to be risk factors for the presence of asNRL-IgE.

Background: Several studies have shown that allergy to natural rubber latex is associated with cross reactivity to other plants. We have investigated a possible cross reactivity with a tree belonging to the Sterculiaceae family, Tryplochiton scleroxylon, in a patient allergic to obeche wood, that began to suffer symptoms of allergy in contact with latex., Methods: Determinations of specific IgE by CAP to obeche, natural rubber latex (NRL) and recombinant allergens of latex were done. Immunoblotting was performed to study allergens detected by serum of our patient. CAP-inhibition methods were used to study cross-reactive between NRL and obeche wood., Results: In obeche extract, 4 bands were found of an apparent molecular weight of 18, 38, 75 and 199 kDa. In NRL extract the allergens have a molecular weight around 18, 21, 32, 38, 60, 70 and 199 kDa. IgE to latex was almost completely inhibited (96%) by the obeche extract in CAP-inhibition studies. Using obeche extract as inhibitor, IgE binding to native hevein (nHevb 6.02) was reduced by 25%., Conclusions: The results obtained in CAP-inhibition demonstrate the existence of cross-reactivity between proteins in NRL and obeche wood. In our patient, a band of apparent molecular weight of 38 kDa could be the most important allergen.

Background: Class I chitinase in natural rubber latex (NRL) has been assumed to be an important allergen, especially concerning its cross-reactivity with fruits like avocado and banana., Objectives: The present study aimed to produce a recombinant latex class I chitinase from Hevea brasiliensis leaves and to study its immunoglobulin (Ig)E-binding reactivity., Methods: A class I chitinase-specific complementary DNA from H. brasiliensis leaves was synthesized, subcloned, sequenced and overexpressed in fusion with the maltose-binding protein (MBP) in Escherichia coli. The IgE-binding reactivity of this protein was studied by the Pharmacia CAP System and by immunoblot experiments using sera from latex-allergic patients., Results: The rHev b 11.0102 was found to have a length of 295 amino acid residues and contains an N-terminal hevein-like domain with a 56% homology to hevein. Analysis by the CAP method revealed the presence of rHev b 11.0102-specific IgE antibodies in 17 of 58 sera (29%) of IgE-mediated latex-allergic subjects tested. Immunoblot analysis of the MBP-rHev b 11.0102 fusion protein and the MBP carrier protein as a negative control confirmed the IgE-reactivity of rHev b 11.0102., Conclusion: Due to its IgE-reactivity rHev b 11.0102 represents an allergen of intermediate prevalence in NRL. Its property to cross-react with certain fruits makes it an important supplement in the diagnostic panel of recombinant NRL allergens.

Background: Potential cross-reactions between natural rubber latex and fruit/vegetable specific immunoglobulin (Ig)E antibodies have been reported for many years. This study was designed to investigate the molecular basis of acquired food sensitization focusing on the storage protein patatin and the patatin-like latex protein Hev b 7., Objective: The amount of potato-specific IgE in the serum of latex-allergic health care workers and children with atopic dermatitis was determined to evaluate cross-reactivity between Hev b 7 and patatin. Additionally, the stability of potato patatin to digestion was investigated., Methods: Human serum was tested on its reactivity to latex and potato proteins by IgE immunoblotting after one-dimensional (1-D) and 2-D electrophoresis. Latex- and potato-specific IgE concentrations were measured in fluorescence enzyme immunoassays (CAP, Pharmacia, Uppsala, Sweden). Further, potato patatin was chromatographically isolated to perform auto-inhibition tests. Stability of patatin to degradation was determined by digestion in vitro., Results: Patatin was identified as major cross-reactive potato allergen by N-terminal sequencing. Seventy-five percent of the potato-sensitized people reacted with patatin in 1-D immunoblots, and 25% of the positive reactions to Hev b 7 could be blocked by preincubation of the patients' sera with purified potato patatin. Examination of children with atopic dermatitis showed that most sera contained patatin-specific IgE, whereas no Hev b 7-specific IgE was detected. Finally, patatin has been found partially stable to digestion in vitro., Conclusions: Patatin was identified as a major cross-reactive protein in latex-associated potato allergy and appears to be relevant for atopic dermatitis. Therefore, patatin could be a suitable marker for the determination of potato sensitization, and it may also constitute an important food allergen. Cross-reactivity between Hev b 7 and patatin was restricted to primarily latex-sensitized adults, suggesting a different mechanism of sensitization in children with atopic dermatitis.

Background: Hevein is one of the most important latex allergens affecting health care workers (HCWs)., Objective: Because the genetically determined susceptibility is one important factor regulating type I allergy, the association between the hevein-specific IgE immune response and HLA class II alleles of DQB1 and DRB1, DRB3, DRB4, and DRB5 was studied., Methods: The distribution of HLA-DQB1 and DRB1, DRB3, DRB4, and DRB5 in 269 HCWs with latex allergy, 56 latex-sensitized patients with spina bifida (SB), and 90 nonatopic control subjects under special consideration for hevein-specific IgE was examined., Results: Seventy percent (189/269) of the HCWs with latex allergy and 39% (22/56) of the latex-sensitized patients with SB had increased hevein-specific IgE antibody concentrations (>0.35 kU/L). HLA data analysis revealed significantly increased phenotype frequencies for DQB1*0302 (DQ8; 91/189 [48%]) and DRB1*04 (DR4; 102/189 [54%]) in hevein-positive HCWs with latex allergy compared with the 80 hevein-negative HCWs with latex allergy (DQB1*0302: 16/80 [20%], corrected P value [P (c)] = 7.1 x 10(-4); DRB1*04: 23/80 [29%], P (c) =.01) and with control subjects (DQB1*0302: 16/89 [18%], P (c) = 1 x 10(-4); DRB1*04: 22/90 [24%], P (c) = 3.2 x 10(-4)). The DQ8-DR4 haplotype frequency was significantly elevated in HCWs with hevein-specific IgE antibodies when compared with that in HCWs without hevein-specific IgE antibodies (47% vs 18%, P (c) = 5.3 x 10(-4)) or control subjects (47% vs 18%, P (c) = 9.6 x 10(-4)). In contrast, latex-sensitized patients with SB with hevein-specific IgE antibodies showed an increased but not significant DQB1*0302 frequency (7/22 [32%] vs 2/34 [6%], P =.02, P (c) = not significant) compared with that seen in those without hevein-specific IgE antibodies., Conclusion: The DQB1*0302 (DQ8) alone, the DQB1*0302 (DQ8)-DRB1*04 (DR4) haplotype, or both are significantly involved in the hevein-specific IgE immune response in HCWs with latex allergy.

Background/objective: Latex allergy is a type 1 hypersensitivity reaction that mainly affects high-risk populations such as health care workers, spina bifida-affected or multiply-operated children. Ten molecules have so far been identified and registered as latex allergens (Hev b 1 to Hev b 10). The aim of the present investigation was to identify the major latex allergens by an individual analysis of the IgE response of latex-allergic patients to latex proteins separated by two-dimensional (2-D) gel electrophoresis., Materials and Methods: Latex proteins from a sap or a glove extract were separated by 2-D electrophoresis and transferred to a nitrocellulose membrane. Each membrane was incubated with the serum of one latex-allergic patient. The most frequently recognized latex allergens were characterized in sap and glove extracts using monoclonal antibodies or amino acid microsequencing., Results: The one-dimensional screening of 54 patient sera revealed 4 major bands recognized by IgE. The 2-D analysis of the sensitization to latex allergens allows the identification of allergen isoforms and the characterization of an individual response diversity. Hev b 6.01 was recognized by 88.9% of the patients. Protein spots around 14 kD were recognized by 48.1% of the patients and corresponded to Hev b 6.03 as well as other proteins. A not yet characterized doublet of acidic proteins with molecular masses of 43 and 94 kD was recognized by 20.4% of the sera. Only 5.5% of the sera did not recognize any of these 4 major allergens. Hev b 1 is the main protein from the glove extract but was not constantly found in sap extracts., Conclusions: One-dimensional electrophoretic analysis of the allergen is usually not sufficient to characterize the individual specificity of the IgE response to latex allergens. Latex-glove proteins which are allergens can be absent from the sap extracts and the sensitization to these allergens could be underestimated. Individual 2-D analysis of the sensitization to latex allergens is useful to define the best allergen mixture required for diagnosis and needed for individual therapy monitoring., (Copyright 2002 S. Karger AG, Basel)

Background: An association between allergy to Ficus benjamina and natural rubber latex (NRL) has been suspected based on clinical and immunological observations. The responsible cross-reactive allergens have not been identified yet. This study was undertaken to investigate the cross-reactivity between hevein (Hev b 6.02, 4.7 kD), a major allergen of NRL, and F. benjamina and identify its counterpart in F. benjamina., Methods: 89 serum samples from subjects allergic to NRL were used in the study. Skin prick tests were performed with highly purified hevein and sap extract of F. benjamina. Specific IgE antibodies to NRL, F. benjamina and Hev b 6.02 were determined by the Pharmacia CAP method. Cross-reactivity among these allergens was investigated by means of CAP and immunoblot inhibition experiments. Two-dimensional gel electrophoresis separation and protein microsequencing were performed to identify the cross-reactive allergens in F. benjamina., Results: 67 out of 89 (75%) sera showed elevated IgE to hevein. Specific IgE to Ficus were found in 22 (24.7%) sera, and with 1 exception, all these sera also had IgE to Hev b 6.02. Results of CAP inhibition assays using 11 sera showing IgE to both Hev b 6.02 and Ficus demonstrated that the IgE to Ficus could be completely inhibited by Hev b 6.02 in 6 of 11 sera. Immunoblots and immunoblot inhibition assays revealed that a protein of about 45 kD in F. benjamina is strongly recognized by serum IgE. In addition, the IgE-binding reactivity to this 45-kD protein could be completely inhibited by preincubation of the sera with Hev b 6.02. N-terminal protein sequencing of 14 amino acids indicated that this 45-kD protein has a hevein-like domain at the N-terminal region and may belong to the endochitinase family., Conclusion: Latex-allergic patients are at higher risk of becoming sensitized to Ficus. Hev b 6.02 in latex is a major cross-reactive allergen and its counterpart in F. benjamina is an acidic protein with a molecular weight of about 45 kD and a hevein-like N-terminal domain., (Copyright 2000 S. Karger AG, Basel)

Background: Hev b 1 represents one of the most important allergens in Hevea brasiliensis latex. It is difficult to get an appropriate amount of native Hev b 1 (nHev b 1) for research purposes., Objective: The aim of this study was to produce sufficient amounts of Hev b 1 by recombinant methods to prove its suitability for latex allergy diagnostics., Methods: We isolated total RNA of Hevea brasiliensis leaves and synthesized cDNA by RT PCR. Recombinant Hev b 1 (rHev b 1) as well as three fragments (amino acid residues 29-137, 48-137, 78-137) were subcloned and expressed as fusion proteins with Maltose-binding protein (MBP) in Escherichia coli. The MBP-rHev b 1 fusion protein was examined by RAST with the CAP method, histamine release test and immunoblots with human sera from spina bifida patients as well as from health care workers with latex allergy and monoclonal antibodies., Results: Histamine release test and immunoblots revealed the high allergenicity of the MBP-rHev b 1 construct. By the CAP method, 54 out of 58 serum samples (93%) from latex-sensitized spina bifida patients previously showing immunoglobulin (Ig) E to nHev b 1 exhibited IgE-binding to rHev b 1. Among 71 latex-allergic health care workers tested, 16 (22.5%) had IgE antibodies to rHev b 1. The analysis of the fusion proteins carrying rHev b 1 fragments revealed that the loss of the N-terminal 28 amino acid residues did not affect IgE-binding. In contrast, the lack of the first 47 amino acid residues led to decreased IgE-binding reactivity in two out of four sera tested, whereas the absence of the N-terminal 77 residues abolished IgE-binding in these two sera., Conclusion: The MBP-rHev b 1 fusion protein exhibits a corresponding IgE-binding reactivity to nHev b 1 and may therefore substitute natural Hev b 1 for both in vitro diagnostics and research purposes.

Background: Recent studies have shown that airborne latex allergens cause allergic rhinitis and bronchial asthma., Objective: The aim of this study was to investigate the association between the development of rhinitis reactions during workplace-related inhalative challenge tests and nasal allergic inflammation., Methods: Thirty-two health care workers (HCWs) with suspected respiratory hypersensitivity to latex allergens underwent an inhalative workplace-related challenge test with powdered latex gloves. Nasal lavage fluid (NALF) and nasal brushing (NAB) material were collected before and after exposure (30 min, 2, 6 and 24 h) to determine mediator and cellular composition. In addition, lung function parameters and nasal flow were recorded. Furthermore, six healthy controls underwent nasal brushing and nasal lavage without latex allergen challenge at the same time intervals., Results: Twenty-six HCWs showed acute rhinitis by contact to airborne latex allergen exposure and 10 of them had an additional asthma response. Only in responders, significantly increased eosinophil levels were found 6 h (P < 0.00001) and 24 h (P < 0.0005) post-challenge when compared with the prechallenge values. The ECP levels measured 2, 6 and 24 h post-challenge in the responder group were significantly elevated when compared with the prechallenge values as well as with the non-responders (6 h: P < 0.05, 24 h: P < 0.00001 afterwards). Only in some concentrated NALF samples of responders collected 30 min post-challenge (seven out of 15) tryptase concentration above the detection limit were found. The NO derivative concentrations in NALF were significantly increased 6 h post-challenge compared with the prechallenge values (P < 0.05) and were significantly higher in responders than in non-responders and in controls (P < 0.002). IL-5 levels increased post-challenge in the responder group with a pronounced effect 6 h after challenge (P < 0.001). Overall, a variety of parameters was significantly correlated (e.g. ECP with NO derivatives, r = 0.792 P < 0.002)., Conclusions: Our data demonstrate for the first time that nasal and bronchial hyperreactivity to airborne latex allergens are associated with an increase of eosinophils and mediators (e.g. ECP, NO derivatives, IL-5, tryptase) in nasal mucosa. The combined use of NAB (for cells) and NALF (for mediators) appears to be a useful model to monitor nasal inflammation during workplace-related challenge tests.

Recent studies have demonstrated that allergy to natural rubber latex (NRL) is associated with cross-reactivity to certain foods. The aim of this study was to investigate the prevalence of NRL sensitization and allergy in children with atopic dermatitis (n=74). We also examined cross-reactions between latex and foods, and compared the frequency of suspected latex cross-reacting fruits in children with and without NRL-specific immunoglobulin E (IgE). Twelve of the 74 atopic children studied (16.2%; 95% confidence interval (CI), 8.7-26.6%) had circulating IgE antibodies to latex. These NRL-sensitized children were older and they showed significantly higher total IgE values (p<0.003) when compared with the group of children without NRL sensitization. Of the specific food IgE evaluations, 18.4% (93 out of 505) were positive, and 69.9% were observed in the group of children with latex-specific IgE, most frequently to potato, tomato, sweet pepper, and avocado. An isolated latex-specific IgE response without food-specific IgE was never observed. Exclusively in the latex-positive group, conformity with the report of allergic symptoms after ingestion of food and increased food-specific IgE was found. Twenty children without proven latex sensitization showed increased food-specific IgE, most frequently to potato, banana, and chestnut. Avocado-specific IgE was never determined in this patient group. No significant differences were detected concerning the sensitization to potato, banana, and kiwi between NRL-sensitized children and the group of 20 children without latex-specific IgE. The competitive CAP inhibition using sera from children with specific IgE to both latex and food showed different cross-reactivities between latex and the specific food. A close relationship existed between latex and avocado (median inhibition: 100%), whereas sensitization to latex and kiwi seemed to be independent in our study group (inhibition: <25%). In particular, for potato, cross-reactivity and co-sensitization existed. Our study demonstrated that children with atopic dermatitis are a high-risk group for latex sensitization. Increasing age, additional sensitization to ubiquitous inhaled allergens, and enhanced total serum IgE values seemed to be important variables for latex sensitization and further sensitization to the latex-associated foods. Cross-reactivity and, in some cases, co-sensitization to specific fruits and vegetables, were observed.

Background: In the medical literature immunoglobulin (Ig)E-mediated sensitization to avocado is rarely reported. On the other hand, more than 50% of subjects having IgE-mediated natural rubber latex allergy are sensitized to avocado fruit as demonstrated by skin-prick testing and/or specific IgE measurements and about 10-20% report hypersensitivity reactions after ingesting avocado., Objective: The underlying pathomechanism of latex-associated avocado allergy is still unknown. The conserved hevein domain of the major latex allergen prohevein (Hev b 6.01) is a ubiquitous chitin-binding protein structure that can be found in several plant proteins and may be responsible for the observed cross-reactivity between latex and avocado fruit., Methods: Chitin-binding avocado proteins (CBAPs) were isolated by affinity-chromatography and their IgE-binding characteristics were studied by immunoblotting using the sera from 15 avocado-sensitized latex patients. Inhibition experiments using isolated hevein and CBAPs as inhibitor solutions were performed to study the immunological cross-reactivity between both protein species and to assess the role of the CBAPs as mediators in latex-associated avocado allergy., Results: In 80% of avocado-sensitized subjects (n = 15), IgE antibodies directed against a 31-kDa allergen were detected by immunoblotting. This IgE-binding protein was identified by protein sequencing to be a class I endochitinase containing a hevein domain at the N-terminus. Purified native and digested (using simulated gastric fluid) endochitinase were able to completely block all avocado-specific IgE antibodies in six out of seven avocado patients., Conclusions: Sensitization to endochitinase class I containing a hevein domain is the main underlying pathomechanism in latex-mediated avocado allergy.

Background: Respiratory symptoms of natural rubber latex (NRL) allergy in health care workers (HCWs) have been reported in rooms with a detectable allergen load. Preventive measures have been proposed to reduce the risk of NRL sensitization., Objectives: Eliminating powdered NRL gloves from the workplace and giving NRL-free material to sensitized workers has been among proposed preventive measures. To appraise the success of such procedures among HCWs, a prospective study was carried out., Methods: Sensitization of HCWs to NRL was determined by skin prick tests and measurements of specific IgE antibodies. NRL allergen concentrations in room air were measured before and after substitution of powdered NRL gloves with powder-free or synthetic gloves in different departments of a hospital and determined by a competitive inhibition immunoassay., Results: The prevalence of HCWs with positive skin prick test responses and NRL-specific IgE-positive HCWs was 8% (n = 7) among the 90 examined staff members before the intervention started. All 7 reported glove-related allergic symptoms. Six of 7 sensitized subjects had a significant decrease of latex-specific IgE antibody concentrations during follow-up examinations in April and September 1997 (P <.003). Within 24 hours after substitution took place, NRL aeroallergen levels (up to 49.9 ng/m3) fell below the detection limit in areas with synthetic gloves or powder-free NRL gloves alike. Use of asthma medication and antiallergic drugs could be discontinued by 2 HCWs with NRL-related respiratory tract symptoms., Conclusions: Our results demonstrate that elimination of powdered NRL gloves is a useful device in reducing aerogen NRL allergen loads below the detection limit and permitting sensitized or allergic personnel to remain on the job.

Background: Recent studies demonstrated that allergy to natural rubber latex is frequently associated with hypersensitivity to avocado fruit. The responsible cross-sensitizing allergen has not been identified., Objective: The purpose of this study was to investigate the cross-reactivity of a latex major allergen, hevein, with avocado proteins., Methods: Serum samples from 118 health care workers (HCWs) allergic to latex (HCW group) and 78 patients with spina bifida (SB) allergic to latex (SB group) were included in this study. Anti-hevein and anti-avocado IgE antibodies were measured by enzyme-linked allergosorbent assay. Cross-reactivity of hevein to avocado proteins was assessed by inhibition of the IgE binding in individual patients' sera containing IgE antibodies to both hevein and avocado., Results: The prevalence of seropositive IgE antibodies to avocado was found to be strongly associated with the presence of hevein-specific IgE antibodies in subjects of both groups (P < .001). Sixty-seven of 91 (73%) subjects from the HCW group and all 19 subjects in the SB group with positive IgE antibodies to hevein also had elevated IgE values to avocado. Competitive RAST inhibition with 42 sera showed that IgE binding to avocado could be completely inhibited in 27 (64%) sera by preincubation with hevein. By contrast, the degrees of inhibition of IgE to hevein by avocado extract ranged from 0% to 36% (n = 16). These results indicate that sensitization to avocado in most patients allergic to latex is caused exclusively by IgE-binding epitopes present in hevein. Results of immunoblots and immunoblot inhibition with 11 serum samples confirmed that a 30-kd protein in avocado was the major IgE-binding component; the IgE-binding reactivity to this protein could be inhibited by hevein in all sera tested., Conclusion: Hevein is the major cross-reacting allergen with avocado in subjects with latex allergy.