Objective: To analyze the characteristics of small airway dysfunction in patients with occupational asthma, and explore the significance of small airway function indicators in the evaluation of occupational asthma. Methods: A total of 53 patients with occupational asthma diagnosed in our hospital from December 2008 to December 2018 were retrospectively collected in May 2020. 55 healthy people were included as the control group (NC group) and 58 bronchial asthma patients as BA group. The general information and baseline pulmonary function (FVC、FEV(1)、PEF) of the subjects were collected, the pulmonary function were reexamined and small airway function (FEF(25%)pred、FEF(50%)pred、FEF(75%)pred、MMEF(25-75%)pred) were tested at the time of diagnosis and remission. Results: There was no significant difference in pulmonary function and asthma control score (ACT) between OA group and BA group (P=0.356, 0.610, 0.364, 0.430, 0.533, 0.759, 0.426, 0.632) . The incidence of small airway dysfunction in OA group was 77.4%. The indexes of small airway function (FEF(25%)pred, FEF(50%)pred, FEF(75%)pred, MMEF(25-75%)pred) were lower than those in the NC group (P<0.001) . The small airway function indexes of mild and moderate OA patients in remission stage were improved (P=0.029, 0.182) , but the abnormal rate of small airway function was still 62.3%, and there was no significant difference compared with those at the time of diagnosis (P=0.091) . Small airway function (MMEF(25-75%)pred, FEF(50%)pred) was correlated with large airway function (FEV(1)% pred, PEF% pred) (P=0.001) . Conclusion: Small airway dysfunction often occurs and persists in patients with occupational asthma, and has a certain correlation with large airway function indexes.
Asthma, Occupational ; Humans ; Lung ; Respiratory Function Tests ; Retrospective Studies

Asthma, Occupational ; Breath Tests ; Exhalation ; Humans ; Lung ; Nitric Oxide ; ROC Curve

PURPOSE: Occupational asthma may be induced by high- or low-molecular weight allergens (HMWA or LMWA, respectively). The study was conducted to compare the pattern of bronchial response in 200 HMWA-induced asthmatics (n = 130) and LMWA-induced asthmatics (n = 70). METHODS: The study participants underwent a single-blind, placebo-controlled specific inhalation challenge (SIC) with workplace allergens, accompanied by evaluation of non-specific bronchial hyperresponsiveness (NSBHR) with methacholine before and after the SIC. RESULTS: A single early bronchial response more frequently occurred in HMWA-induced asthmatics than in LMWA-induced asthmatics (86.2% vs. 20%). An isolated late bronchial response or atypical patterns were more frequently observed in LMWA-induced asthmatics than in LMWA-induced asthmatics (45.7% vs. 3.8% or 34.3% vs. 10%, respectively). Baseline NSBHR before SIC was more often detected in LMWA-induced asthmatics than in HMWA-induced asthmatics (81.4% vs. 54.6%), and the median value of the provocation concentration of methacholine was relevantly lower in these patients before and after SIC. A significant 3-fold increase in NSBHR after SIC was observed more often in LMWA-induced asthmatics than in HMWA-induced asthmatics (82.8% vs. 66.1%). In addition, compared to LMWA-induced asthmatics, HMWA-induced asthmatics were older, were more frequently active smokers, showed lower level of NSBHR, and more frequently continued their work in harmful occupational exposure. CONCLUSIONS: The results of this study suggest that HMWA-induced asthmatics may have milder clinical courses and that there is a possibility of job continuation despite asthma exacerbation requiring medical surveillance.
Allergens ; Asthma ; Asthma, Occupational ; Bronchial Hyperreactivity ; Humans ; Immunoglobulin E ; Inhalation ; Methacholine Chloride ; Molecular Weight ; Occupational Exposure ; Prognosis

For the past three decades, a large number of genetic studies have been performed to examine genetic variants associated with asthma and its subtypes in hopes of gaining better understanding of the mechanisms underlying disease pathology and to identify genetic biomarkers predictive of disease outcomes. Various methods have been used to achieve these objectives, including linkage analysis, candidate gene polymorphism analysis, and genome-wide association studies (GWAS); however, the degree to which genetic variants contribute to asthma pathogenesis has proven to be much less significant than originally expected. Subsequent application of GWAS to well-defined phenotypes, such as occupational asthma and non-steroidal anti-inflammatory drugexacerbated respiratory diseases, has overcome some of these limitations, although with only partial success. Recently, a combinatorial analysis of single nucleotide polymorphisms (SNPs) identified by GWAS has been used to develop sets of genetic markers able to more accurately stratify asthma subtypes. In this review, we discuss the implications of the identified SNPs in diagnosis of asthma and its subtypes and the progress being made in combinatorial analysis of genetic variants.
Anti-Inflammatory Agents, Non-Steroidal ; Aspirin ; Asthma* ; Asthma, Occupational ; Biomarkers ; Diagnosis* ; Genetic Association Studies ; Genetic Markers ; Genetic Techniques ; Genome-Wide Association Study ; Hope ; Pathology ; Phenotype ; Polymorphism, Single Nucleotide*

BACKGROUND: Metalworking fluids (MWFs) are mixtures with inhalation exposures as mists, dusts, and vapors, and dermal exposure in the dispersed and bulk liquid phase. A quantitative risk assessment was performed for exposure to MWF and respiratory disease.METHODS: Risks associated with MWF were derived from published studies and NIOSH Health Hazard Evaluations, and lifetime risks were calculated. The outcomes analyzed included adult onset asthma, hypersensitivity pneumonitis, pulmonary function impairment, and reported symptoms. Incidence rates were compiled or estimated, and annual proportional loss of respiratory capacity was derived from cross-sectional assessments.RESULTS: A strong healthy worker survivor effect was present. New-onset asthma and hypersensitivity pneumonitis, at 0.1 mg/m3 MWF under continuous outbreak conditions, had a lifetime risk of 45%; if the associated microbiological conditions occur with only 5% prevalence, then the lifetime risk would be about 3%. At 0.1 mg/m3, the estimate of excess lifetime risk of attributable pulmonary impairment was 0.25%, which may have been underestimated by a factor of 5 or more by a strong healthy worker survivor effect. The symptom prevalence associated with respiratory impairment at 0.1 mg/m3 MWF was estimated to be 5% (published studies) and 21% (Health Hazard Evaluations).CONCLUSION: Significant risks of impairment and chronic disease occurred at 0.1 mg/m3 for MWFs in use mostly before 2000. Evolving MWFs contain new ingredients with uncharacterized long-term hazards.
Adult ; Alveolitis, Extrinsic Allergic ; Asthma ; Asthma, Occupational ; Chronic Disease ; Dust ; Humans ; Incidence ; Inhalation Exposure ; National Institute for Occupational Safety and Health (U.S.) ; Prevalence ; Risk Assessment ; Survivors

Bronchial asthma causes great morbidity and mortality worldwide. Certain occupations especially those exposed to known triggers of asthma such as animal fur, dusts or solvents may trigger asthma attacks in a previously undiagnosed individual or worsen its’ control in a known asthmatic. This is especially true for adult-onset asthma. This may in turn the health of the affected workers and affect their productivity. Affected workers may be given job reassignment and eligible for medical compensation from Social Security Organisation (SOSCO). This case report will look at how two individuals in very distinct occupation were diagnosed with suspected occupational asthma
Occupational asthma

Work-related asthma is the most common occupational lung disease encountered in clinical practice. In adult asthmatics, work-relatedness can account for 15%–33% of cases, but delays in diagnosis remain common and lead to worse outcomes. Accurate diagnosis of asthma is the first step to managing occupational asthma, which can be sensitizer-induced or irritant-induced asthma. While latency has traditionally been recognized as a hallmark of sensitizer-induced asthma and rapid-onset a defining feature of irritant-induced asthma (as in Reactive Airway Dysfunction Syndrome), there is epidemiological evidence for irritant-induced asthma with latency from chronic moderate exposure. Diagnostic testing while the patient is still in the workplace significantly improves sensitivity. While specific inhalational challenges remain the gold-standard for the diagnosis of occupational asthma, they are not available outside of specialized centers. Commonly available tests including bronchoprovocation challenges and peak flow monitoring are important tools for practicing clinicians. Management of sensitizer-induced occupational asthma is notable for the central importance of removal from the causative agent: ideally, removal of the culprit agent; but if not feasible, this may require changes in the work process or ultimately, removal of the worker from the workplace. While workers' compensation programs may reduce income loss, these are not universal and there can be significant socio-economic impact from work-related asthma. Primary prevention remains the preferred method of reducing the burden of occupational asthma, which may include modification to work processes, better worker education and substitution of sensitizing agents from the workplace with safer compounds.
Adult ; Asthma ; Asthma, Occupational ; Case Management ; Diagnosis ; Diagnostic Tests, Routine ; Education ; Humans ; Lung Diseases ; Methods ; Primary Prevention ; Workers' Compensation

PURPOSE: Toluene diisocyanate (TDI) is a leading cause of occupational asthma (OA). Periostin is a matricellular protein implicated in type 2 immunity-driven asthma. Its pathogenic role in TDI-OA has not been completely elucidated. The present study was performed to investigate the role of periostin in TDI-OA. MATERIALS AND METHODS: Serum periostin levels were measured in subjects with TDI-OA, asymptomatic TDI-exposure controls (AECs), non-occupational asthmatics (NAs), and unexposed normal controls (NCs). To understand the mechanism by which TDI induces periostin production, primary small airway epithelial cells (SAECs) were cultured under stimulation of TDI and neutrophils from asthmatic patients. RESULTS: Fifty-three subjects with TDI-OA, 71 AECs, 67 NAs, and 83 NCs were enrolled. Serum periostin levels were significantly higher in TDI-OA subjects than in AECs (p=0.001), NAs (p < 0.001), and NCs (p < 0.001). In TDI-exposed subjects (TDI-OA and AEC), the PC20 methacholine levels were significantly lower in subjects with a higher periostin level than in those with a lower periostin level. TDI exposure did not increase periostin production directly by SAECs; however, periostin production increased significantly after co-culture with TDI and neutrophils, which was suppressed by an antioxidant. In addition, increased release of TGF-β1 was noted from SAECs when exposed to TDI and neutrophils, which was also suppressed by an antioxidant. CONCLUSION: These results suggest that an increased periostin level may contribute to the progression of airway inflammation to remodeling in TDI-exposed workers. A high serum periostin level is a potential serologic marker of the phenotype of TDI-OA.
Asthma ; Asthma, Occupational* ; Coculture Techniques ; Epithelial Cells ; Humans ; Inflammation ; Methacholine Chloride ; Neutrophils ; Phenotype ; Reactive Oxygen Species ; Toluene 2,4-Diisocyanate ; Toluene*

Bronchial provocation tests are of value in the evaluation of airway hyperresponsiveness. Nonspecific bronchial challenge (methacholine, mannitol, exercise, etc.) is used when the symptoms, physical examination, and measurements of pulmonary function are unremarkable in the diagnosis of asthma, when a patient is suspected of having occupational asthma or exercise-induced bronchoconstriction (EIB), and when a screening test for asthma or EIB is required for some occupational groups in whom bronchospasm would pose an unacceptable hazard. Methacholine inhalation challenge is most widely used pharmacologic challenge and highly sensitive. For appropriate interpretation of the results of methacholine provocation, it is important to perform the test with the standardized protocol and to recognize that inhalation methods significantly influence the sensitivity of the procedure. Indirect challenges (e.g., mannitol and exercise) correlate with airway inflammation and are more specific but less sensitive for asthma. Indirect provocation tests are used to confirm asthma, to differentiate asthma from other airway diseases, and to evaluate EIB.
Asthma ; Asthma, Occupational ; Bronchial Provocation Tests ; Bronchial Spasm ; Bronchoconstriction ; Diagnosis ; Exercise Test ; Humans ; Inflammation ; Inhalation ; Mannitol ; Mass Screening ; Methacholine Chloride ; Occupational Groups ; Physical Examination

Toluene diisocyanate (TDI) exposure can directly activate and damage airway epithelium. Folliculin (FLCN) is a protein expressed by human airway epithelial cells (HAECs) to maintain airway epithelial integrity and survival. This study investigated the involvement of FLCN in the pathogenesis of TDI-induced occupational asthma (OA). Enzyme-linked immunosorbent assay was used to measure serum levels of FLCN in TDI-exposed subjects (93 TDI-OA patients and 119 asymptomatic exposed controls (AEC)), 200 non-occupational asthma (NOA) patients and 71 unexposed healthy normal controls (NCs). Significantly more subjects in the TDI-OA and AEC groups had high serum levels of FLCN compared to those in the NOA group (P=0.002 and P=0.001, respectively), all of which were higher than the NC group (all P<0.001). The serum level of FLCN was positively correlated with TDI exposure duration (r=0.251, P=0.027), but was negatively correlated with asthma duration of TDI-OA patients (r=−0.329, P=0.029). TDI-exposed subjects with high FLCN levels had higher serum levels of total IgE than those with lower levels. The effects of TDI exposure on FLCN production was investigated by treating HAECs (A549 cells) with TDI-human serum albumin conjugate, which showed increased expression and release of FLCN and interleukin-8 from HAECs. Co-culture with peripheral blood neutrophils also induced FLCN expression and release from HAECs. In conclusion, TDI exposure and TDI-induced neutrophil recruitment into the airways can activate and stimulate HAECs to produce FLCN, which could be involved in airway inflammation in workers exposed to TDI.
Asthma ; Asthma, Occupational ; Coculture Techniques ; Enzyme-Linked Immunosorbent Assay ; Epithelial Cells ; Epithelium ; Estrone* ; Humans ; Immunoglobulin E ; Inflammation* ; Interleukin-8 ; Neutrophil Infiltration ; Neutrophils ; Serum Albumin ; Toluene 2,4-Diisocyanate* ; Toluene*