Ex vivo\textit {Ex vivo} cytokine release and pattern recognition receptor expression of subjects exposed to dampness

In rooms with moisture damage, the indoor air can be enriched with microorganisms causing a variety of symptoms. Due to the highly diverse composition of bioaerosols and the multiple effects on humans, an assessment of the health risk is not sufficiently possible. The aim of this study was to characterize the features of innate immunity using blood from subjects exposed to moisture damage compared to control subjects living in houses without visible moisture damage. We investigated the expression of TLR-2, TLR-4 and dectin-1 on the surface of monocytes from both fresh blood and after $\textit {in vitro}$ stimulation with the model substances $\textit {E. coli}$ endotoxin, zymosan A, $Pam_{3}Cys$ and $\textit {Aspergillus versicolor}$ in 25 exposed subjects and 25 control subjects. $\textit {In vitro}$ stimulation of whole blood with the same components was performed for 20 h and the release of inflammatory mediators IL-8 and IL-1$\beta$ were quantified. In addition to an enhanced number of blood leucocytes, the expression of the receptors TLR-2, TLR-4 and dectin-1 on blood monocytes was significantly enhanced in exposed subjects. In contrast, no different alteration in expression was detected between exposed and control group after $\textit {in vitro}$ stimulation with the model substances. The release of IL-8 and IL-1$\beta$ after stimulation of whole blood with $\textit {A. versicolor}$ was increased in subjects exposed to moisture damage. Furthermore, in the exposed subjects the IL-1$\beta$ release was significantly enhanced after $\textit {in vitro}$ stimulation with $\textit {E. coli}$ endotoxin (1000 pg/mL). In conclusion, features of the innate immune system (receptor expression and mediator release of monocytes) are altered in subjects exposed to moisture damage which may be a potential explanation for the increased incidence of respiratory health diseases observed in these populations

Exposure levels of animal allergens, endotoxin, and β\beta-(1,3)-glucan on a university campus of veterinary medicine

$\bf Objectives$ The study aimed to determine the allergen, endotoxin and $\beta$-(1,3)-glucan concentrations at various areas on a university campus of veterinary medicine. $\bf Methods$ Dust samples were collected four times a year for three years using electrostatic dust collectors (EDC) at 25 different locations on a campus of veterinary medicine and in laboratories of inorganic chemistry as a control area representing animal-free environment. Major animal allergens from dog, cat, horse, cattle and mouse, domestic mite (DM) allergens, and $\beta$-(1,3)-glucan were measured using enzyme immunoassays and endotoxin using the limulus amoebocyte lysate (LAL) assay. Seasonal, annual and local influences on exposure levels were analyzed using Bayesian mixed models. $\bf Results$ With the exception of mouse allergens, all other determinants were found in almost all locations on the campus and in the control area, but in up to 10.000-fold variable concentrations. By far the highest levels of feline, canine, equine and bovine allergens were detected in buildings where the respective species were examined. The highest levels of mouse and DM allergens, $\beta$-(1,3)-glucan and endotoxin occurred together and were associated with locations where large animals were present. In buildings without animals, allergen levels were considerably lower but still elevated at several locations compared to the control area, especially for dog and horse allergens, and $\beta$-(1,3)-glucan. Significant seasonal effects were observed for dog, cat, horse and DM allergens, and $\beta$-(1,3)-glucan. Variations between years were less apparent than between seasons (except for $\beta$-(1,3)-glucan). $\bf Conclusions$ The strongest influencing factor on the concentration of mammalian allergens was the presence of the corresponding animal at the collection site. Seasonal influence on allergen concentrations was observed, while the overall exposure remained constant over the years. At locations with horses, elevated levels of mite allergens, endotoxin, and $\beta$-(1,3)-glucan can be expected, probably due to passive transfer from stable environment

Comparing the concentration levels of allergens and endotoxins in employees' homes and offices

$\bf Objective$ The aim of the study was to find out whether allergen and endotoxin concentrations in offices differ from those measured at the homes of employees, and identify the parameters that influence exposure. $\bf Methods$ Electrostatic dust collectors (EDCs) were placed in five office buildings (68 rooms, 436 EDCs), as well as the homes of the office workers (145 rooms, 405 EDCs) for 14 days, four times a year. In addition, surface samples were collected from the offices four times a year by vacuuming the carpeted floors. Domestic mite (DM), and the major cat and dog allergens (Fel d 1 and Can f 1) were quantified in all samples using fluorescence enzyme immunoassays. Endotoxin was measured in the EDC samples, using the Limulus amoebocyte lysate assay. The allergen and endotoxin concentrations were log transformed and analysed with multilevel models. $\bf Results$ Endotoxin concentrations were significantly higher in personal homes compared to levels measured in the offices, and depended on the number of persons living in each household, as well as the presence of a dog. DM allergens were significantly higher in households than in offices, and were significantly higher in bedrooms compared to living rooms. Offices occupied by cat owners had significantly higher Fel d 1 concentrations than offices or homes without. Additionally, Can f 1 concentrations were significantly higher in offices occupied by dog owners compared to those without. $\bf Conclusions$ Pet owners appear to transfer cat and dog allergens to their offices. Therefore, in case of allergy complaints at the office, employers and physicians might consider possible contamination by cat and dog allergens

No inflammatory effects after acute inhalation of barium sulfate particles in human volunteers

$\bf Background:$ Most threshold limit values are based on animal experiments. Often, the question remains whether these data reflect the situation in humans. As part of a series of investigations in our exposure lab, this study investigates whether the results on the inflammatory effects of particles that have been demonstrated in animal models can be confirmed in acute inhalation studies in humans. Such studies have not been conducted so far for barium sulfate particles ($BaSO_{4}$), a substance with very low solubility and without known substance-specific toxicity. Previous inhalation studies with zinc oxide (ZnO), which has a substance-specific toxicity, have shown local and systemic inflammatory respones. The design of these human ZnO inhalation studies was adopted for $BaSO_{4}$ to compare the effects of particles with known inflammatory activity and supposedly inert particles. For further comparison, in vitro investigations on inflammatory processes were carried out. $\bf Methods:$ Sixteen healthy volunteers were exposed to filtered air and $BaSO_{4}$ particles ($4.0 mg/m^{3}$) for two hours including one hour of ergometric cycling at moderate workload. Effect parameters were clinical signs, body temperature, and inflammatory markers in blood and induced sputum. In addition, particle-induced in vitro-chemotaxis of $BaSO_{4}$ was investigated with regard to mode of action and differences between in vivo and in vitro effects. $\bf Results:$ No local or systemic clinical signs were observed after acute $BaSO_{4}$ inhalation and, in contrast to our previous human exposure studies with ZnO, no elevated values of biomarkers of inflammation were measured after the challenge. The in vitro chemotaxis induced by $BaSO_{4}$ particles was minimal and 15-fold lower compared to ZnO. $\bf Conclusion:$ The results of this study indicate that $BaSO_{4}$ as a representative of granular biopersistent particles without specific toxicity does not induce inflammatory effects in humans after acute inhalation. Moreover, the in vitro data fit in with these in vivo results. Despite the careful and complex investigations, limitations must be admitted because the number of local effect parameters were limited and chronic toxicity could not be studied

Health effects after inhalation of micro- and nano-sized zinc oxide particles in human volunteers

Inhalation of ZnO particles can cause inflammation of the airways and metal fume fever. It is unclear if different sizes of the particles alter these effects. However, various studies report higher biological activity of other nano-sized particles compared to microparticles. No effects at all were observed after inhalation of micro- and nano-sized zinc oxide (ZnO) particle concentrations of $0.5 mg/m^{3}$. Studies with different particle sizes of ZnO at higher exposures are not available. Accordingly, we hypothesized that inhalation of nano-sized ZnO particles induces stronger health effects than the inhalation of the same airborne mass concentration of micro-sized ZnO particles. 16 healthy volunteers (eight men, eight women) were exposed to filtered air and ZnO particles ($2.0 mg/m^{3}$) for 2 h (one session with nano- and one with micro-sized ZnO) including 1 h of cycling at moderate workload. Effect parameters were symptoms, body temperature, inflammatory markers in blood and in induced sputum. Induced sputum was obtained at baseline examination, 22 h after exposure and at the end of the final test. The effects were assessed before, immediately after, about 22 h after, as well as two and three days after each exposure. Neutrophils, monocytes and acute-phase proteins in blood increased 22 h after micro- and nano-sized ZnO exposure. Effects were generally stronger with micro-sized ZnO particles. Parameters in induced sputum showed partial increases on the next day, but the effect strengths were not clearly attributable to particle sizes. The hypothesis that nano-sized ZnO particles induce stronger health effects than micro-sized ZnO particles was not supported by our data. The stronger systemic inflammatory responses after inhalation of micro-sized ZnO particles can be explained by the higher deposition efficiency of micro-sized ZnO particles in the respiratory tract and a substance-specific mode of action, most likely caused by the formation of zinc ions

Domestic mite antigens in floor and airborne dust at workplaces in comparison to living areas

$\textit {Objectives}$: Allergens produced by domestic mites (DM) are among the most common allergic sensitizers and risk factors for asthma. To compare exposure levels between workplaces and living areas a new assay able to measure airborne DM antigen concentrations was developed. $\textit {Methods}$: At workplaces and in living areas, 213 floor dust samples and 92 personal inhalable dust samples were collected. For sensitive quantification of DM antigens, a new enzyme immunoassay (EIA) based on polyclonal antibodies to $\textit {Dermatophagoides farinae}$ extract was developed. Reactivity of five house dust mite and four storage mite species was tested. All dust samples were tested with the new EIA and with the Der f 1 and Der p 1-EIAs (Indoor Biotechnologies, UK) which detect major allergens from $\textit {D. farinae}$ and $\textit {D. pteronyssinus}$ by monoclonal antibodies. Samples below the detection limit in the DM-EIA were retested in an assay variant with a fluorogenic substrate (DM-FEIA). $\textit {Results}$: The newly developed DM-EIA detects antigens from all nine tested domestic mite species. It has a lower detection limit of 200 pg/ml of $\textit {D.farinae}$ protein, compared to 50 pg/ml for the DM-FEIA. DM antigens were detected by DM-EIA/FEIA in all floor dust and 80 (87%) of airborne samples. Der f 1 was found in 133 (62%) floor dust and in only 6 airborne samples, Der p 1 was found in 70 (33%) of floor samples and in one airborne sample. Der f 1 and DM concentrations were highly correlated. DM-antigens were significantly higher in inhalable airborne samples from textile recycling, bed feather filling, feed production, grain storage and cattle stables in comparison to living areas. $\textit {Conclusions}$: A new sensitive EIA directed at DM antigens was developed. DM antigen quantities were well correlated to Der f 1 values and were measurable in the majority (87%) of airborne dust samples. Some workplaces had significantly higher DM antigen concentrations than living areas

Lower allergen levels in hypoallergenic Curly Horses?

$\textbf {Background:}$ Exposure to horses can cause severe allergic reactions in sensitized individuals. The breed, American Bashkir Curly Horse is categorized as hypoallergenic, primarily due to reports of allergic patients experiencing fewer symptoms while handling this special breed. The possible reasons for this phenomenon could be lower allergen production and/or reduced allergen release into the air because of increased sebum content in their skin and hair compared to other breeds. Therefore, the aim of the current study was to compare different horse breeds in relation to allergen content in hair and airborne dust samples. $\textbf {Methods:}$ In total, 224 hair samples from 32 different horse breeds were investigated. Personal nasal filters were used to collect airborne dust during the grooming of 20 Curly Horses and 20 Quarter Horses. Quantitative analysis of all samples was performed using two newly developed immunoassays for the detection of horse dander (HD) antigens and the major allergen Equ c 1 and the commercial assay for Equ c 4. Results were analyzed using multiple linear regression models for hair samples and the Mann Whitney U test for airborne samples. $\textbf {Results:}$ Horse antigen and allergen levels differed up to four orders of magnitude between individual animals. Despite enormous variability, levels of HD antigen, Equ c 1 and Equ c 4 in hair were significantly related to the breed and gender combined with the castration status of male animals. Curly Horses had significantly higher concentrations of all three tested parameters compared to the majority of the investigated breeds (medians: 11800 $\mu$g/g for HD antigen, 2400 $\mu$g/g for Equ c 1, and 258 kU/g for Equ c 4). Tinker Horses, Icelandic Horses and Shetland Ponies were associated with approximately 7-fold reduced levels of HD antigen and Equ c 1, and up to 25-fold reduced levels of Equ c 4 compared to Curly Horses. Compared to mares, stallions displayed increased concentrations of HD antigens, Equ c 1 and Equ c 4 by a factor 2.2, 3.5 and 6.7, respectively. No difference was observed between mares and geldings. No differences in airborne allergen concentrations collected with personal nasal filters during grooming were found between Curly and Quarter Horses. $\textbf {Conclusion:}$ Breed and castration status had a significant influence on the antigen and allergen levels of horse hair. However, these differences were smaller than the wide variability observed among individual horses. Compared to other breeds, Curly Horses were not associated with lower allergen levels in hair and in air samples collected during grooming. Our approach provides no molecular explanation why Curly Horses are considered to be hypoallergenic

Naphthalene

$\bf Objective$ This cross-sectional study determined whether acute sensory irritative or (sub)chronic inflammatory effects of the eyes, nose or respiratory tract are observed in employees who are exposed to naphthalene at the workplace. $\bf Methods$ Thirtynine healthy and non-smoking male employees with either moderate ($\it n$ = 22) or high ($\it n$ = 17) exposure to naphthalene were compared to 22 male employees from the same plants with no or only rare exposure to naphthalene. (Sub)clinical endpoint measures included nasal endoscopy, smell sensitivity, self-reported work-related complaints and the intensity of naphthalene odor and irritation. In addition, cellular and soluble mediators in blood, nasal lavage fluid (NALF) and induced sputum (IS) were analysed. All measurements were carried out pre-shift on Monday and post-shift on Thursday. Personal air monitoring revealed naphthalene shift concentrations up to 11.6 $mg/m^{3}$ with short-term peak concentrations up to 145.8 $mg/m^{3}$ and 1- and 2-naphthol levels (sum) in post-shift urine up to 10.1 mg/L. $\bf Results$ Acute sensory irritating effects at the eyes and upper airways were reported to occur when directly handling naphthalene (e.g., sieving pure naphthalene). Generally, naphthalene odor was described as intense and unpleasant. Habituation effects or olfactory fatigue were not observed. Endoscopic examination revealed mild inflammatory effects at the nasal mucosa of exposed employees in terms of reddening and swelling and abnormal mucus production. No consistent pattern of cellular and soluble mediators in blood, NALF or IS was observed which would indicate a chronic or acute inflammatory effect of naphthalene in exposed workers. $\bf Conclusions$ The results suggest that exposure to naphthalene induces acute sensory irritative effects in exposed workers. No (sub)chronic inflammatory effects on the nasal epithelium or the respiratory tract could be observed under the study conditions described here

Upper and lower respiratory airway complaints among female veterinary staff

$\bf Objective$ Working with animals is characterized by exposure to particulate, biological or chemical matter, and respiratory complaints are common. The aim of our cross-sectional study was to assess the prevalence of respiratory symptoms and diagnoses among veterinary staff. $\bf Methods$ Participants working in veterinary practices were examined and a detailed questionnaire was used to collect data. IgE tests to common and animal allergens were performed to specify sensitization. Associations with respiratory outcomes were analysed using logistic regression models while controlling for potential confounders. $\bf Results$ Atopy was seen in 31% of the 109 female participants. Symptoms of rhinoconjunctivitis were the most frequent complaints ($\it n$ = 92; 84%). In 18% the diagnosis was confirmed by physicians. Symptoms of upper and lower airways were highly correlated and an asthma diagnosis was confirmed in 11% of participants. Modelling revealed that sensitization against cats/dogs was a significant risk factor for respiratory symptoms of upper [odds ratio (OR) 4.61; 95% confidence interval (CI) 1.13–18.81] and lower airways (OR 5.14; 95% CI 1.25–21.13), physician-confirmed rhinoconjunctivitis (OR 13.43; 95% CI 1.69–106.5) and asthma (OR 9.02; 95% CI 1.16–70.39) in assistant staff of small-animal practices. $\bf Conclusions$ In several cases, rhinoconjunctivitis worsened after entering the profession. Atopy and specific sensitization to cats/dogs were risk factors for health impairments. Thus, to implement preventive measures, veterinary practice staff should be educated that upper respiratory tract symptoms are not harmless and should be diagnosed and treated early