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

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

The new latex allergen hev b 15: IgE-binding properties of a recombinant serine protease inhibitor

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Multiple wheat flour allergens and cross-reactive carbohydrate determinants bind IgE in baker's asthma.

BACKGROUND: Several wheat flour allergens relevant to baker's asthma have been identified in the last 25 years. The aim of this study was to determine the frequency of sensitization to these allergens in German bakers. METHODS: Using recombinant DNA technology, the following wheat flour allergens were cloned, expressed in Escherichia coli and purified: five subunits of the wheat α-amylase inhibitors (WTAI-CM1, WTAI-CM2, WTAI-CM3, WDAI-0.19 and WMAI-0.28), thioredoxin, thiol reductase or 1-cys-peroxiredoxin homologues, triosephosphate-isomerase, αß-gliadin, serpin, glyceraldehyde-3-phosphate-dehydrogenase, a nonspecific lipid transfer protein (nsLTP), dehydrin, profilin and peroxidase. In addition, ImmunoCAPs with the recombinant allergen ω-5-gliadin and two cross-reactive carbohydrate determinants (CCDs), horse radish peroxidase (HRP) and the N-glycan of bromelain (MUXF), were used. Specific IgE was measured in wheat flour-positive sera from 40 German bakers with work-related asthma/rhinitis and 10 controls with pollinosis. RESULTS: Thirty bakers (75%) had IgE to at least one of the 19 single allergens. Most frequent was IgE to WDAI-0.19, HRP and MUXF (25% each), followed by WTAI-CM1 (20%), thiol reductase (16%), WTAI-CM3 (15%), WTAI-CM2 and thioredoxin (12.5%), WMAI-28, triosephosphate-isomerase, αß-gliadin (10%), 1-cys-peroxiredoxin (7.5%), dehydrin, serpin, glyceraldehyde-3-phosphate-dehydrogenase (5%), ω-5-gliadin, nsLTP and profilin (2.5%). Fifteen bakers (38%) had IgE to any α-amylase inhibitor and 12 (30%) to at least one CCD. The controls reacted exclusively to CCDs (80%), profilin (60%), thioredoxin (30%), triosephosphate isomerase and nsLTP (10%). CONCLUSIONS: The single allergen sensitization profiles obtained with 17 recombinant wheat flour allergens and two CCDs revealed no major allergen for German bakers. The highest frequencies were found for α-amylase inhibitors and CCDs.

[DNA repair: from the mechanisms to the impact on occupational research]. / DNA-Reparatur: Von den Mechanismen zur Bedeutung in der arbeitsmedizinischen Forschung.

The human genome comprises more than three billion base pairs and a part of this information is responsible for the control of cell proliferation. Different internal and external factors are able to affect DNA and could influence the proliferation process. As a consequence critical diseases may occur. To prevent such harmful occurrences, the human body contains multiple repair enzymes that allow for the immediate elimination of DNA damage. Since each individual exhibits a set of gene variants with different properties, each person possesses his/her individual spectrum of DNA repair gene variants. For this reason, the first step of current studies is to obtain more information about the impact of DNA variants in repair enzymes in connection with certain occupational exposures with the aim to use this information in epidemiological models to calculate in which manner such variants are able to modulate DNA adducts or biomonitoring parameters.

Occupational risks for adenocarcinoma of the nasal cavity and paranasal sinuses in the German wood industry.

OBJECTIVES: To examine the risk of wood dust and chemical exposures for adenocarcinoma of the nasal cavity and paranasal sinuses (ADCN) among German wood workers. METHODS: An industry-based case-control study with 86 male ADCN cases and 204 controls was conducted in the German wood-working industries. Cumulative and average wood-dust exposure was quantified with a job-exposure matrix based on wood-dust measurements at recent and historical workplaces. Probabilities of exposure to wood preservatives, stains, varnishes, and formaldehyde were semi-quantitatively rated. Odds ratios and 95% confidence intervals were calculated with logistic regression analysis conditional on age and adjusted for smoking and other factors. For estimating the risks of either wood dust or chemical additives, the authors additionally adjusted for the corresponding co-exposure. RESULTS: ADCN occurred relatively more frequently among wood workers that had ever worked as cabinet makers or joiners (OR 2.96, 95% CI 1.46 to 6.01) than as saw millers (OR 0.15, 95% CI 0.03 to 0.68). Average exposure to inhalable wood dust >/=5 mg/m(3) was associated with a high risk (OR 48.47, 95% CI 13.30 to 176.63) compared to levels below 3.5 mg/m(3). Assuming 40 years of exposure under these concentrations, the corresponding OR was 4.20 (95% CI 1.69 to 10.43). Exposure between 3.5 and 5 mg/m(3) was also found to pose a risk (OR 10.54, 95% CI 3.34 to 33.27). Exposure to pigment stains before 1970 was associated with an increased risk (OR 3.03; 95% CI 1.11 to 8.26). No significant associations were estimated for wood preservatives, varnishes, and formaldehyde. CONCLUSIONS: The authors found an elevated ADCN risk for exposure to inhalable wood dust above 3.5 mg/m(3). The rareness of the disease does not allow the exclusion of risk below that concentration. For pigment stains, there is evidence for an association of historical exposure with the development of ADCN in German wood workers.

Quantitative analysis of immunoglobulin E reactivity profiles in patients allergic or sensitized to natural rubber latex (Hevea brasiliensis).

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.

IgE reactivity to latex allergens among sensitized healthcare workers before and after immunotherapy with latex.

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.

Characterization of B- and T-cell responses and HLA-DR4 binding motifs of the latex allergen Hev b 6.01 (prohevein) and its post-transcriptionally formed proteins Hev b 6.02 and Hev b 6.03.

BACKGROUND: Multiple immunoglobulin E (IgE)-binding proteins in natural rubber latex extracts have been identified. In the case of Hev b 6 a differentiation was made between the precursor protein prohevein (Hev b 6.01) and its two post-transcriptionally formed proteins, the N-terminal hevein (Hev b 6.02) and the C-terminal domain (Hev b 6.03). All three components act as independent allergens. The aim of this study was a detailed analysis of the T-cell responses and the IgE-binding capacity of Hev b 6.01, Hev b 6.02 and Hev b 6.03 by using these allergens as recombinant maltose-binding fusion (MBP) proteins and the usage of synthetic modified hevein peptides. METHODS: Latex-allergic health care workers (HCWs) suffering from rhinitis, conjunctivitis, contact urticaria and/or asthma with increased specific IgE-antibodies to latex were tested for their IgE-binding capacity and T-cell reactivity (by proliferation response) to the recombinant MBP-rHev b 6.01, MBP-rHev b 6.02, MBP-rHev b 6.03, to native Hev b 6.02, to modified hevein peptides and wheat germ agglutinin (WGA). For testing of the human leucocyte antigen (HLA) class II restriction of MBP-rHev b 6.01 induced peripheral blood mononuclear cell (PBMC) responses, monoclonal antibodies against HLA-DR, HLA-DP or HLA-DQ were added. RESULTS: Seventeen of 18 (94%) serum samples from latex-allergic HCWs had increased levels of specific IgE to MBP-rHev b 6.01, 16 (89%) to MBP-rHev b 6.02 and 13 (72%) to MBP-rHev b 6.03. A significant difference existed between the specific IgE-values of MBP-rHev b 6.02 and MBP-rHev b 6.03 (P < 0.01). Proliferation responses of PBMC of the same 18 latex-allergic patients were positive for MBP-rHev b 6.01 and MBP-rHev b 6.03 in 83 and 67% of the tested PBMC suspension, whereas the proliferation responses induced with MBP-rHev b 6.02 or native Hev b 6.02 were very low (5.6 and 22.2%). Sera from nine additional latex-allergic patients showed specific IgE binding to the native Hev b 6.02, but none of these sera showed specific IgE binding to the modified Hev b 6.02-peptides [whereby all eight cysteine residues were substituted by serine (C --> S) or by alanine (C --> A)]. Proliferation responses induced by the modified Hev b 6.02 peptides were not significantly different from that induced by Hev b 6.02. Potential HLA-DR4Dw4(DRB1*0401)-restricted T-cell epitopes of Hev b 6.01 predicted by two computer algorithms were only found in the Hev b 6.03-part of Hev b 6.01. CONCLUSION: In the Hev b 6.01 precursor the regions responsible for IgE binding and those for inducing the T-cell proliferation responses are settled in different parts of the protein. The Hev b 6.02 domain is responsible for IgE binding and carries discontinuous B-cell epitopes whereas Hev b 6.03 is a better inducer of a proliferation response and contains HLA-DR4-binding motifs.

Molecular cloning, purification, and IgE-binding of a recombinant class I chitinase from Hevea brasiliensis leaves (rHev b 11.0102).

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.

Analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine and DNA strand breaks in white blood cells of occupationally exposed workers: comparison with ambient monitoring, urinary metabolites and enzyme polymorphisms.

The relationship between biomarkers of effect (8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo, HPLC system) and tail extent moment (comet assay)), markers of external and internal exposure, and biomarkers of susceptibility was evaluated for coke-oven and graphite-electrode-producing plant workers exposed to polycyclic aromatic hydrocarbons (PAHs). Mean 8-oxodGuo levels in white blood cells (WBC) of exposed workers were between 1.38 times (coke-oven, n = 20; P < 0.01) and 2.15 times (graphite-electrode-producing plant, n = 30; P < 0.01) higher than levels found in control samples (mean +/- SD 0.52 +/- 0.16 8-oxodGuo/10(5) dGuo, n = 47). The mean tail extent moment in lymphocytes was 1.38 times higher for coke-oven workers (n = 19; P = 0.09) and 3.13 times higher for graphite-electrode-producing plant workers (n = 29; P < 0.01) when compared with controls (mean plus minus SD 2.54 +/- 0.68, n = 32). Elevated tail extent moments (>3.73) were found in the majority (84%) of PAH-exposed workers showing increased DNA adduct levels (>0.78 8-oxodGuo/10(5) dGuo). However, no association (P > 0.05) was found between DNA damage (8-oxodGuo/10(5) dGuo or tail extent moment) in WBC of all PAH-exposed workers and either benzo[a]pyrene levels or the sum of 16 PAH levels in the air at work place. Furthermore, no relation (P > 0.05) could be established between DNA damage in WBC and biomarkers of internal exposure (1-hydroxypyrene (1-OHP) and sum of five hydroxyphenanthrenes (OHPHs)). Higher exposure to airborne pyrene and phenanthrene led to increasing concentrations of the metabolites 1-OHP (P < 0.01) and the sum of five OHPHs (P < 0.01) in the urine of PAH-exposed workers. The polymorphisms of genes CYP1A1, GSTM1, GSTT1 and GSTP1 (biomarkers of susceptibility) showed no association with biomarkers of effect. In conclusion, both biomarkers of effect may be appropriate for further surveillance studies of workers under PAH exposure.