Vera van Kampen

Occupational immediate-type asthma and rhinitis due to rhodium salts.

BACKGROUND Whereas platinum salts are well known occupational allergens, rhodium salts have not been identified as inhalative sensitizing substances. METHODS A 27-year-old atopic operator of an electroplating plant developed work-related shortness of breath and runny nose with sneezing after exposure to rhodium salts. Quantitative skin prick tests (SPT) and bronchial challenge tests with a dosimeter protocol were performed with quadrupling doses of the sodium chloride salts of rhodium (Na(3)RhCl(6)) and platinum (Na(2)PtCl(6)). RESULTS The patient showed positive SPT reactions and positive bronchial immediate-type reactions with rhodium and platinum salts. Sensitivity to rhodium salt was much higher than to platinum salt; the molar concentrations differed by a factor of 256 in SPT and a factor of 16 in bronchial challenges. CONCLUSIONS Rhodium salts should be considered as occupational immediate-type allergens.

Symptoms, Spirometry, and Serum Antibody Concentrations Among Compost Workers Exposed to Organic Dust

Work-related symptoms and diseases of 190 currently exposed compost workers, 59 former compost workers, and 38 nonexposed control subjects were investigated in a cross-sectional study. Using a standardized questionnaire, participants were asked for work-related symptoms, exposures to bioaerosols, atopic diseases, and smoking habits. The subjects underwent a physical examination and a lung function test. In addition, total immunoglobulin (Ig) E, IgE specific to environmental allergens and moulds, and IgG specific to molds and actinomycetes were quantified. Compared to controls, compost workers suffered more often from cough and irritation of the eyes in terms of mucosal membrane irritation (MMI). Former compost workers reported similar work-related complaints, but most MMI symptoms had improved after termination of bioaerosol exposure. In contrast, cough and dyspnea persisted, indicating a chronic process. Lung function parameters of compost workers were within the reference ranges. Nevertheless, forced vital capacity (FVC) was significantly lower than for controls. Specific IgE to environmental allergens and molds was positive in 25.3% and 7.4%, respectively, of currently exposed compost workers. There were no marked differences in IgE and IgG concentrations among the three groups. Compost workers suffered with a higher frequency from cough and MMI symptoms. The findings that MMI symptoms improved in former compost workers after leaving the job confirmed the association with bioaerosol exposure. Further, the reduced FVC may be produced by this exposure. There was no higher frequency of mold sensitization in the group of compost workers compared to controls, which may be an indication of a healthy worker survivor effect.

Development of a Monoclonal Antibody-Based Sandwich ELISA for Detection of the Latex Allergen Hev b 1

Background: Natural rubber latex (NRL) products are complex mixtures consisting of different allergenic components. Among them, Hev b 1 belongs to the important and well-characterized ones. To quantify the relevant allergen Hev b 1 in NRL products, a two-site monoclonal antibody (mAb)-based assay was developed. Methods: Two Hev b 1-specific mAbs with different epitope recognition and ability to bind simultaneously to an Hev b 1 molecule were used in the study. Both mAbs (II4F9 and II4G9) were enriched by in vitro production in a modular minifermenter and affinity purified. Wells of micro-ELISA plates coated with captured mAb II4G9 were incubated with samples containing Hev b 1. Bound Hev b 1 was detected by a combination of biotinylated mAb II4F9 as detection antibody and peroxidase-labeled avidin. Results: The optimized sandwich ELISA was highly reproducible in the linear range of the standard curve and Hev b 1 concentrations ranging from 12.5 to 400 ng/100 μl could be detected. The assay was suitable for the detection of Hev b 1 concentrations in latex sap and latex products, e.g. gloves, with a detection limit of 1.25 μg of Hev b 1/g of rubber. In a preliminary study with five different brands of latex gloves, Hev b 1 concentrations were found to be in the range of 18–40 μg per gram of rubber material, corresponding to 2–4% of the total extractable protein content in latex glove extracts. Conclusions: A sensitive sandwich assay was developed to quantify the latex allergen Hev b 1. This assay can be used to standardize latex extracts with regard to the content of the major allergen Hev b 1.

Outcome of occupational latex allergy--work ability and quality of life.

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.

Concentration of Bioaerosols in Composting Plants Using Different Quantification Methods

BACKGROUND Bioaerosols (organic dusts) containing viable and non-viable microorganisms and their metabolic products can lead to adverse health effects in exposed workers. Standard quantification methods of airborne microorganisms are mainly based on cultivation, which often underestimates the microbial burden. The aim of the study was to determine the microbial load in German composting plants with different, mainly cultivation-independent, methods. Second purpose was to evaluate which working areas are associated with higher or lower bioaerosol concentrations. METHODS A total of 124 inhalable dust samples were collected at different workplaces in 31 composting plants. Besides the determination of inhalable dust, particles, and total cell numbers, antigen quantification for moulds (Aspergillus fumigatus, Aspergillus versicolor, Penicillium chrysogenum, and Cladosporium spp.) and mites was performed. Concentrations of β-glucans as well as endotoxin and pyrogenic activities were also measured. The number of colony forming units (cfu) was determined by cultivation of moulds and actinomycetes in 36 additional dust samples. RESULTS With the exception of particle numbers, concentrations of all determined parameters showed significant correlations (P < 0.0001; r Spearman: 0.40-0.80), indicating a close association between these exposure markers. Colony numbers of mesophilic moulds and actinomycetes correlated also significantly with data of cultivation-independent methods. Exposure levels showed generally large variations. However, all parameters were measured highest in dusty working areas like next to the shredder and during processing with the exception of Cladosporium antigens that were found in the highest concentrations in the delivery area. The lowest concentrations of dust, particles, antigens, and pyrogenic activity were determined in wheel loader cabins (WLCs), which were equipped with an air filtration system. CONCLUSION It was possible to assess the microbial load of air in composting plants with different quantification methods. Since allergic and toxic reactions may be also caused by nonliving microorganisms, cultivation-independent methods may provide additional information about bioaerosol composition. In general, air filtration reduced the bioaerosol exposure shown in WLCs. Due to the fact that the mechanical processing of compost material, e.g. by shredding or sieving is associated with the generation of high bioaerosol concentrations, there is still a need of improved risk assessment and state-of-the-art protective measures in composting plants.

Analysis of b-cell epitopes in the n-terminal region of Chi t I component III using monoclonal antibodies

The hemoglobins of the midge Chironomus thummi thummi (Chi t I) are known to cause immediate-type hypersensitivity reactions in humans. Further knowledge of the antigenic sites of such allergens will provide new therapeutic approaches. The aim of our study was to identify and characterize linear B-cell epitopes of the hemoglobin component III of Chi t I (136 amino acid residues). Using the antigenic index algorithm of Jameson and Wolf (Jameson and Wolf (1988) Comput. Appl. Biosci. 4, 181-186), three linear binding sequences of this allergen molecule were predicted. Two mouse monoclonal antibodies (mAbs 3 and 6) raised against purified Chi t I component III were investigated by ELISA for their binding to nine synthetic peptides 19-21 residues in length, covering nearly the whole sequence of component III. MAb 6 recognized only one peptide (11-30) while mAb 3 bound to both N-terminal peptides (1-19 and 11-30), suggesting that the antibody binding site is located in the overlapping region. This assumption could be confirmed in ELISA with solid phase-bound recombinant peptides (RP) as well as in inhibition studies with free tryptic peptides indicating that identification of these linear B-cell epitopes is neither influenced by the method of peptide production nor by the kind of used immunoassay. To define the essential amino acid residues we investigated mAbs with solid phase-bound overlapping octamers. In the case of mAb 3, amino acids experimentally identified as essential for antibody binding (aa 13-17) are identical with those residues predicted as a B-cell epitope with the antigenic index of Jameson and Wolf.

Assessment of Airborne Exposure to Endotoxin and Pyrogenic Active Dust Using Electrostatic Dustfall Collectors (EDCs)

Passive airborne dust sampling using electrostatic dustfall collectors (EDCs) is one possibility especially for long sampling periods. In this study, EDCs were deposited in living rooms of private households and in social rooms of composting plants. The aim of the study was to determine whether endotoxin and pyrogenic activity are measurable using EDCs. In all extracts, endotoxin (via Limulus amebocyte lysate [LAL] assay) and pyrogenic activity (interleukin [IL]-1β release via whole blood assay) were detectable. In addition, the monocyte chemotactic protein (MCP-1; CCL-2) as a secondary proinflammatory marker was measured with whole blood assay. Endotoxin activity and proinflammatory/pyrogenic activity of EDC extracts from social rooms in composting plants were higher compared to extracts obtained from EDCs in private household rooms. A significant correlation between LAL assay and whole blood assay was detectable. In conclusion, EDC sampling is an applicable method to evaluate settled dust from airborne bioaerosols displaying a longer period of exposure. The extraction of EDC without Tween enables one to measure endotoxin as well as proinflammatory/pyrogenic activity using the same sample for parallel detection and more reliable characterization of the airborne bioaerosol contamination.

Prevalence of and relationship between rhinoconjunctivitis and lower airway diseases in compost workers with current or former exposure to organic dust.

INTRODUCTION AND OBJECTIVE The relationship between allergic rhinitis and allergic asthma is well characterized. However, it remains unknown whether an association exists between symptoms of upper and lower airway diseases and occupational bioaerosol exposure beyond the scope of allergy. MATERIALS AND METHODS The current cross-sectional study focuses on 190 current and 59 former compost workers exposed to bioaerosols. Work-related symptoms indicative of conjunctivitis, rhinitis and lower airway irritation were assessed and compared with 38 non-exposed control subjects. Allergic asthma was diagnosed using a calculated score, and chronic obstructive pulmonary disease (COPD) was spirometrically determined. RESULTS 12 current, 8 former and 5 non-exposed subjects were diagnosed with allergic asthma and excluded from further analysis. Multivariate logistic regression models suggested that cough and chronic bronchitis in current compost workers were associated with eye irritation (OR 2.75 (0.93-8.07); OR 7.22 (1.12-46.5)). Chronic bronchitis in former workers was strongly associated with work-related eye irritation (OR 38.6 (1.33->1000) and nose irritation (OR 25.0 (1.21-513)). CONCLUSIONS After excluding allergic asthmatics, there was no evidence that eye or nose irritation was due to an underlying atopic disease, but rather to non-allergic mucous membrane irritation syndrome. Therefore, the higher incidence of chronic bronchitis in former compost workers may reflect a chronic irritative process triggered by exposure to bioaerosols.

Development and Application of Mold Antigen-Specific Enzyme-Linked Immunosorbent Assays (Elisa) to Quantify Airborne Antigen Exposure

The aim of our study was to develop specific enzyme-linked immunosorbent assays (ELISAs) and apply these to assess mold antigen exposure in composting plants. Sandwich ELISAs based on polyclonal antibodies to Aspergillus fumigatus (Af), Penicillium chrysogenum (Pc), and Cladosporium herbarum (Ch) antigens were developed and validated. Reactivity to 18 different mold species was tested. To optimize extraction procedure, inhalable dust samples taken by a parallel sampler were extracted with or without homogenization. In 31 composting plants stationary pumps were installed at 4 sites to collect 124 inhalable dust samples. The newly developed ELISAs were used in addition to an anti β-1,3-glucan ELISA to quantify mold antigens. The Cladosporium ELISA showed less than 0.04% reactivity to extracts from other fungal genera, while the Af ELISA demonstrated a reactivity of up to 3.6% and the Pc ELISA reacted up to 11% to other mold species. Extraction of parallel sampled filters gave higher antigen amounts with homogenization. The increase was highest for Pc-antigens, followed by Af-antigens, and lowest for Ch-antigens. Mean lower detection limits of homogenized inhalable dust samples were 5 ng/m3 (Af), 0.6 ng/m3 (Pc), 0.2 ng/m3 (Ch), and 0.6 ng/m3 (β-1,3-glucan). The ELISAs were able to detect antigens in 43% (Af), 37% (Pc), 94% (Ch), or 100% (β-1,3-glucan) of the 124 airborne dust samples. Inhalable dust, β-1,3-glucan, and Af-, Pc-, and Ch-antigen concentrations were significantly correlated. The newly developed mold antigen ELISAs are thus able to measure airborne exposure levels in composting plants and differentiate between distinct fungi genera.

Serial measurements of exhaled nitric oxide at work and at home: a new tool for the diagnosis of occupational asthma.

Whereas serial measurements of lung function at work and at home are a well-known diagnostic tool for the diagnosis of occupational asthma (OA), little is known about the serial measurements of non-invasive parameters such as exhaled nitric oxide (eNO). A 51-year-old baker with variable shortness of breath without relation to work was examined for suspected OA. Skin prick test showed weak sensitizations to wheat and rye flour (without sensitizations to environmental allergens) that were corroborated by in vitro testing (CAP class 3). Baseline FEV1 of 58% predicted and a decrease of forced expiratory volume in 1 s (FEV1) after placebo (sugar powder) of 17% did not allow inhalational challenge testing. The patient performed daily measurements of FEV1 and eNO for about a month during a holiday at home and at work. Whereas symptoms and FEV1 did not show differences between holidays and work periods, eNO showed a clear increase from below 10 ppb to a maximum of 75 ppb. A diagnosis of bakers asthma was made, and the patient quit his job immediately after medical advice. A year afterwards, the patient was still taking asthma medication, but his symptoms had improved, FEV1 had increased to 73% predicted, and eNO was 25 ppb. We conclude that serial measurements of eNO at home and at work may be a useful tool for the diagnosis of OA.