Hypersensitivity Pneumonitis and Related Conditions in the Work Environment

Multisystemic Beryllium Disease: An Exceptional Case Revealed by a Urinary Tract Granulomatosis

Chronic beryllium disease (CBD), or berylliosis, is an interstitial lung disease caused by the chronic inhalation of finely particulate beryllium, frequently mistaken for sarcoidosis. It is rarely associated with skin nodular lesions, asymptomatic granulomatous hepatitis or calcium nephrolithiasis. To date, it has never been reported as a diffused multi-organ granulomatous disease. A 60-year-old Pakistani man, a former excavation worker with ancient history of suspected sarcoidosis, underwent a left nephroureterectomy for suspected papillary kidney carcinoma. The histopathological analysis showed a benign non-necrotic granulomatous infiltration of the renal pelvis and ureter. Six months later, he suffered from two consecutive episodes of acute kidney failure. Bladder biopsies found similar noncaseous granulomatosis and kidney biopsies showed interstitial nephritis. Known for suspected asthma, sleep apnea, and usual interstitial pneumonia, the patient would regularly consult for episodes of pyrexia, chills, nocturnal coughing, and wheezing. As kidney function gradually worsened, he ultimately started hemodialysis and was transferred to our facility. A positive blood beryllium lymphocyte proliferation test confirmed the diagnosis of CBD. This original report is the first description of multi-organ berylliosis with diffused urothelial granulomatosis and pseudo-tumor. The patient's pulmonary disease is minimal compared with renal and urinary tract involvement, eventually responsible for end-stage kidney disease. Berylliosis usually responds to glucocorticoids. This case report highlights the importance of evoking the diagnosis of CBD in the presence of any granulomatosis, even extra-thoracic, especially if associated with pulmonary symptoms, however atypical.

Muc5b plays a role in the development of inflammation and fibrosis in hypersensitivity pneumonitis induced by Saccharopolyspora rectivirgula

Previously we have shown that a gain-of-function MUC5B promoter variant (rs35705950) is the strongest risk factor for the development of idiopathic pulmonary fibrosis. We have also found that Muc5b overexpression reduces mucociliary clearance in mice, potentially leading to recurrent injury to the bronchoalveolar epithelia. Hypersensitivity pneumonitis (HP) is induced by inhalation of numerous causative antigens that may be affected by mucociliary clearance. We conducted this study to determine the role of Muc5b in a mouse model of HP induced by Saccharopolyspora rectivirgula (SR) antigen. We used Muc5b-deficient and wild-type (WT) mice to determine whether Muc5b plays a role in inflammation and fibrosis at 3 and 6 wk in an SR model of HP. We measured cell concentrations and MUC5B expression in whole lung lavage (WLL) and quantified fibrosis using hydroxyproline assay and second harmonic generation. Muc5b expression in WLL fluid was significantly increased in SR-exposed WT mice compared with saline controls. WT mice challenged with SR developed more inflammation and lung fibrosis at 6 wk compared with 3 wk postexposure. Moreover, we found that 6 wk following challenge with SR, Muc5b-deficient mice had less lung inflammation and less lung fibrosis than Muc5b WT mice. Furthermore, Muc5b-deficient mice had significantly lower concentrations of TGF-β1 in the WLL compared with Muc5b WT mice at 6 wk of exposure. Muc5b appears to play a role in fibrosis in the animal model of HP and this may have implications for HP in humans.

Granulomatous Sarcoidosis Mimics

Many granulomatous diseases can mimic sarcoidosis histologically and in terms of their clinical features. These mimics include infectious granulomatous diseases, granulomatous reactions to occupational and environmental exposures, granulomatous drug reactions, vasculitides and idiopathic granulomatous conditions. It is important to distinguish sarcoidosis from these mimics, as a misdiagnosis of these diseases may have serious consequences. This manuscript reviews numerous sarcoidosis mimics and describes features of these diseases that may allow them to be differentiated from sarcoidosis. Distinguishing features between sarcoidosis and its mimics requires a careful review of the medical history, symptoms, demographics, radiographic findings, histologic features, and additional laboratory data. Understanding the clinical characteristics of sarcoidosis and its mimics should lead to more accurate diagnoses and treatment of granulomatous disorders that should improve the care of these patients. As the diagnostic criteria of sarcoidosis are not standardized, it is possible that some of these sarcoidosis mimics may represent varied clinical presentations of sarcoidosis itself.

Japanese guidelines for occupational allergic diseases 2020

Occupational allergic diseases are likely to worsen or become intractable as a result of continuous exposure to high concentrations of causative allergens. These are socioeconomically important diseases that can lead to work interruptions for patients and potentially job loss. We published the first guideline for managing occupational allergic diseases in Japan. The original document was published in Japanese in 2013, and the following year (2014) it was published in English. This guideline consists of six chapters about occupational asthma, occupational allergic rhinitis, occupational skin diseases, hypersensitivity pneumonitis, occupational anaphylaxis shock, and the legal aspects of these diseases. Providing general doctors with the knowledge to make evidence-based diagnoses and to understand the occupational allergic disease treatment policies, was a breakthrough in allergic disease treatment. Due to the discovery of new occupational allergens and the accumulation of additional evidence, we published a revised version of our original article in 2016, and it was published in English in 2017. In addition to including new knowledge of allergens and evidence, the 2016 revision contains a "Flowchart to Diagnosis" for the convenience of general doctors. We report the essence of the revised guidelines in this paper.

Genetic variability of T cell responses in hypersensitivity pneumonitis identified using the BXD genetic reference panel

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that may progress to fibrosis and significant risk of death. HP develops following repeated exposures to inhaled environmental antigens; however, only a fraction of the exposed population develops the disease, suggesting that host genetics contribute to disease susceptibility. We used the BXD family of mice with the Saccharopolyspora rectivirgula (SR) model of HP to investigate the role of genetics in susceptibility to HP. The BXD family is derived from a B6 mother and a D2 father and has been used to map susceptibility loci to numerous diseases. B6, D2, and BXD progeny strains were exposed to SR for 3 wk, and the development of HP was monitored. The B6 and D2 strains developed alveolitis; however, the cellular composition was neutrophilic in the D2 strain and more lymphocytic in the B6 strain. Hematoxylin-eosin staining of lung sections revealed lymphoid aggregates in B6 lungs, whereas D2 lungs exhibited a neutrophilic infiltration. Twenty-eight BXD strains of mice were tested, and the results reveal significant heritable variation for numbers of CD4⁺ or CD8⁺ T cells in the air spaces. There was significant genetic variability for lymphoid aggregates and alveolar wall thickening. We mapped a significant quantitative trait locus (QTL) on chromosome 18 for CD8⁺CD69⁺ T cells that includes cadherin 2 (Cdh2), an excellent candidate gene associated with epithelial-mesenchymal transition, which is upregulated in lungs of strains with HP. These results demonstrate that the BXD family is a valuable and translationally relevant model to identify genes contributing to HP and to devise early and effective interventions.

Spirometric Pulmonary Restriction in Herbicide-Exposed U.S. Vietnam War Veterans

Spirometric restriction in herbicide-exposed U.S. Army Chemical Corps Vietnam War veterans was examined because no published research on this topic in Vietnam War veterans exists. Spirometry was conducted on 468 veterans who served in chemical operations in a 2013 study assessing the association between chronic obstructive pulmonary disease (COPD) and herbicide exposure. Exposure was verified based on blood serum values of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Further, the association between herbicide exposure and spirometry restriction (forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) ≥ lower limit of normal (LLN) and FVC < LLN) was tested after adjustment for military characteristics, selected anthropometrics, and other predictors using multivariable regression. Spirometric restriction in herbicide sprayers (15.7%, 95% CI: 10.6, 20.9) was almost twice that of nonsprayers (9.91%, 95% CI: 5.9, 13.9) (p = 0.081). While spirometric restriction was not significantly associated with herbicide exposure (adjusted odds ratio (aOR) = 1.64, 95% CI: 0.82, 3.29) despite the greater prevalence of restriction in sprayers versus nonsprayers, spirometric restriction was significantly associated with race/ethnicity (aOR = 3.04, 95% CI: 1.36, 6.79) and waist circumference (aOR = 2.46, 95% CI: 1.25, 4.85). Because restrictive pulmonary disease may result from chemically-induced inflammation or sensitivity, research on chemical exposures and restriction in veterans should continue. Future study should include full pulmonary function testing, targeted research designs, and a wider set of explanatory variables in analysis, such as other determinants of health.

Progressive plasterer's pneumoconiosis complicated by fibrotic interstitial pneumonia: a case report

BACKGROUND

Although the prevalence of pneumoconiosis has been decreasing due to improvements in working conditions and regular health examinations, occupational hygiene measures are still being established. Plasterers encounter a number of hazardous materials that may be inhaled in the absence of sufficient protection.

CASE PRESENTATION

A 64-year-old man who plastered without any dust protection for more than 40 years was referred to our hospital with suspected interstitial pneumonia. Mixed dust pneumoconiosis and an unusual interstitial pneumonia (UIP) pattern with fibroblastic foci were diagnosed by video-assisted thoracoscopic surgery, and an elemental analysis detected elements included in plaster work materials. Despite the cessation of plaster work and administration of nintedanib, the patient developed advanced respiratory failure.

CONCLUSION

Plasterers are at an increased risk of pneumoconiosis and may have a poor prognosis when complicated by the UIP pattern. Thorough dust protection and careful monitoring are needed.

Hypersensitivity pneumonitis: Antigen diversity and disease implications

Hypersensitivity pneumonitis (HP) is an immune-mediated syndrome triggered by inhalation of a wide variety of allergens, to which an individual has previously been sensitized. More than 200 agents responsible for the disease have already been identified; however, HP occurs only in a small number of individuals exposed to causal antigens. The present report provides an overview of the role of antigen role in HP, highlighting its diversity, research methods, and prevention strategies, as well as the impact on disease prognosis following elimination of antigen. HP is an underdiagnosed disease and, therefore, it is difficult to accurately estimate its incidence. Triggering antigens can be divided into six broad categories: bacteria, fungi, mycobacteria, animal and plant proteins, chemicals, and metals, represented by disease prototypes. The identification of causal antigen is a major challenge; it is impossible to obtain in about 30-60% of cases. The acute form of HP, with early detection and immediate eviction of causal antigen, tends to have an excellent prognosis. In the chronic form, partial recovery of disease is still possible; however, some cases tend to progress to fibrosis, even after removal from exposure. In conclusion, HP diagnosis should be based on a proactive search for potential antigen sources, although their identification is hampered by the lack of standardized methods of demonstrating the specific antigen sensitization. Antigen avoidance is a critical determinant in disease prognosis.

Japanese guidelines for occupational allergic diseases 2017

In 2013, a guideline for occupational allergic diseases was published for the first time in Japan. Occupational allergic diseases are likely to worsen or become intractable as a result of continuous exposure to high concentrations of causative antigens, and are socioeconomically important diseases with which the patients might sometimes lose jobs due to work interruptions. Guidelines for occupational allergic diseases have been published in many countries. This guideline consists of six chapters about occupational asthma, occupational allergic rhinitis, occupational skin diseases, hypersensitivity pneumonitis and occupational anaphylaxis shock, and legal aspects of these diseases. The guideline is characterized with the following basic structure: Clinical Questions (CQs) are set with reference to Minds (Medical Information Network Distribution Service), statements by the committee are correspondingly listed, recommended grades and evidence levels are defined, and then descriptions and references are indicated.

Occupational Allergies: A Brief Review

Occupational allergies are groups of work-related disorders that are accompanied by immunologic reaction to workplace allergens and include occupational asthma, rhinitis, hypersensitivity pneumonitis, dermatitis, and anaphylaxis. This mini review presents a brief analysis of the more important aspects of occupational allergic disorders.

Occupational hypersensitivity pneumonitis: an EAACI position paper

The aim of this document was to provide a critical review of the current knowledge on hypersensitivity pneumonitis caused by the occupational environment and to propose practical guidance for the diagnosis and management of this condition. Occupational hypersensitivity pneumonitis (OHP) is an immunologic lung disease resulting from lymphocytic and frequently granulomatous inflammation of the peripheral airways, alveoli, and surrounding interstitial tissue which develops as the result of a non-IgE-mediated allergic reaction to a variety of organic materials or low molecular weight agents that are present in the workplace. The offending agents can be classified into six broad categories that include bacteria, fungi, animal proteins, plant proteins, low molecular weight chemicals, and metals. The diagnosis of OHP requires a multidisciplinary approach and relies on a combination of diagnostic tests to ascertain the work relatedness of the disease. Both the clinical and the occupational history are keys to the diagnosis and often will lead to the initial suspicion. Diagnostic criteria adapted to OHP are proposed. The cornerstone of treatment is early removal from exposure to the eliciting antigen, although the disease may show an adverse outcome even after avoidance of exposure to the causal agent.

Hypersensitivity Pneumonitis

Chronic exposure to a broad array of antigens after workers inhale aerosolized organic dust particles from mold, animal dander, bird droppings, and chemicals, especially pesticides or herbicides, increases risk for hypersensitivity pneumonitis. Several demographic characteristics of immigrant workers in farming, poultry processing, construction, and landscaping increase this worker population’s risk.

Chronic hypersensitivity pneumonitis caused by Saccharopolyspora rectivirgula is not associated with a switch to a Th2 response

Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease that develops following repeated exposure to inhaled environmental antigens. The disease results in alveolitis and granuloma formation and may progress to a chronic form associated with fibrosis; a greater understanding of the immunopathogenic mechanisms leading to chronic HP is needed. We used the Saccharopolyspora rectivirgula (SR) mouse model of HP to determine the extent to which a switch to a Th2-type immune response is associated with chronic HP. Exposure of wild-type (WT) and tlr2/9(-/-) mice to SR for 14 wk resulted in neutrophilic and lymphocytic alveolitis that was not dependent on Toll-like receptors (TLRs) 2 and 9. Long-term exposure of WT mice to SR resulted in a significant increase in collagen deposition, protein leakage, and IL-1α accompanied by a decrease in quasistatic compliance and total lung capacity compared with unexposed mice. This was associated with an increase in IL-17 but not IL-4 production or recruitment of Th2 cells. tlr2/9(-/-) mice exhibited an increase in protein leakage but less IL-1α and collagen deposition in the lungs compared with WT mice, yet they still displayed a decrease in quasistatic compliance, although total lung capacity was not affected. These mice exhibited an increase in both IL-13 and IL-17, which suggests that IL-13 may ameliorate some of the lung damage caused by long-term SR exposure. Our results suggest that lung pathology following long-term SR exposure in WT mice is associated with the IL-17 response and that TLRs 2 and 9 may inhibit the development of the IL-13/Th2 response.

Chemical determinants of occupational hypersensitivity pneumonitis

BACKGROUND

Workplace inhalational exposures to low molecular weight (LMW) chemicals cause hypersensitivity pneumonitis (HP) as well as the more common manifestation of respiratory hypersensitivity, occupational asthma (OA).

AIMS

To explore whether chemical causation of HP is associated with different structural and physico-chemical determinants from OA.

METHODS

Chemical causes of human cases of HP and OA were identified from searches of peer-reviewed literature up to the end of 2011. Each chemical was categorized according to whether or not it had been the attributed cause of at least one case of HP. The predicted asthma hazard was determined for each chemical using a previously developed quantitative structure-activity relationship (QSAR) model. The chemicals in both sets were independently and 'blindly' analysed by an expert in mech anistic chemistry for a qualitative prediction of protein cross-linking potential and determination of lipophilicity (log K ow).

RESULTS

Ten HP-causing chemicals were identified and had a higher median QSAR predicted asthma hazard than the control group of 101 OA-causing chemicals (P < 0.01). Nine of 10 HP-causing chemicals were predicted to be protein cross-linkers compared with 24/92 controls (P < 0.001). The distributions of log K ow indicated higher values for the HP list (median 3.47) compared with controls (median 0.81) (P < 0.05).

CONCLUSIONS

These findings suggest that chemicals capable of causing HP tend to have higher predicted asthma hazard, are more lipophilic and are more likely to be protein cross-linkers than those causing OA.

Japanese Guideline for Occupational Allergic Diseases 2014

In 2013, a guideline for occupational allergic diseases was published for the first time in Japan. Occupational allergic diseases are likely to worsen or become intractable as a result of continuous exposure to high concentrations of causative antigens, and are socioeconomically important diseases with which the patients might sometimes lose jobs due to work interruptions. Guidelines for occupational allergic diseases have been published in many countries. This guideline consists of six chapters about occupational asthma, occupational allergic rhinitis, occupational skin diseases, hypersensitivity pneumonitis and occupational anaphylaxis shock, and legal aspects of these diseases. The guideline is characterized with the following basic structure: Clinical Questions (CQs) are set with reference to Minds (Medical Information Network Distribution Service), statements by the committee are correspondingly listed, recommended grades and evidence levels are defined, and then descriptions and references are indicated.

Lung transplantation for hypersensitivity pneumonitis

BACKGROUND

Hypersensitivity pneumonitis (HP) is an inhaled antigen-mediated interstitial lung disease (ILD). Advanced disease may necessitate the need for lung transplantation. There are no published studies addressing lung transplant outcomes in HP. We characterized HP outcomes compared with referents undergoing lung transplantation for idiopathic pulmonary fibrosis (IPF).

METHODS

To identify HP cases, we reviewed records for all ILD lung transplantation cases at our institution from 2000 to 2013. We compared clinical characteristics, survival, and acute and chronic rejection for lung transplant recipients with HP to referents with IPF. We also reviewed diagnoses of HP discovered only by explant pathology and looked for evidence of recurrent HP after transplant. Survival was compared using Kaplan-Meier methods and Cox proportional hazard modeling.

RESULTS

We analyzed 31 subjects with HP and 91 with IPF among 183 cases undergoing lung transplantation for ILD. Survival at 1, 3, and 5 years after lung transplant in HP compared with IPF was 96%, 89%, and 89% vs 86%, 67%, and 49%, respectively. Subjects with HP manifested a reduced adjusted risk for death compared with subjects with IPF (hazard ratio, 0.25; 95% CI, 0.08-0.74; P = .013). Of the 31 cases, the diagnosis of HP was unexpectedly made at explant in five (16%). Two subjects developed recurrent HP in their allografts.

CONCLUSIONS

Overall, subjects with HP have excellent medium-term survival after lung transplantation and, relative to IPF, a reduced risk for death. HP may be initially discovered only by review of the explant pathology. Notably, HP may recur in the allograft.

Application of clinico-radiologic-pathologic diagnosis of diffuse parenchymal lung diseases in children in China

Diffuse parenchymal lung diseases in children (chDPLD) or interstitial lung diseases in children (chILD) represent a heterogeneous group of respiratory disorders that are mostly chronic and associated with high morbidity and mortality. However, the incidence of chDPLD is so low that most pediatricians lack sufficient knowledge of chDPLD, especially in China. Based on the clinico-radiologic-pathologic (CRP) diagnosis, we tried to describe (1) the characteristics of chDPLD and (2) the ratio of each constituent of chDPLD in China. Data were evaluated, including clinical, radiographic, and pathologic results from lung biopsies. We collected 25 cases of chDPLD, 18 boys and 7 girls with a median age of 6.0 years, from 16 hospitals in China. The most common manifestations included cough (n = 24), dyspnea (n = 21), and fever (n = 4). There were three cases of exposure-related interstitial lung disease (ILD), three cases of systemic disease-associated ILD, nineteen cases of alveolar structure disorder-associated ILD, and no cases of ILD specific to infancy. Non-specific interstitial pneumonia (n = 9) was the two largest groups.

CONCLUSION

Non-specific interstitial pneumonia is the main categories of chDPLD in China. Lung biopsy is always a crucial step in the final diagnosis. However, clinical and imaging studies should be carefully evaluated for their value in indicating a specific chDPLD.

Setting Occupational Exposure Limits for Chemical Allergens--Understanding the Challenges

Chemical allergens represent a significant health burden in the workplace. Exposures to such chemicals can cause the onset of a diverse group of adverse health effects triggered by immune-mediated responses. Common responses associated with workplace exposures to low molecular weight (LMW) chemical allergens range from allergic contact dermatitis to life-threatening cases of asthma. Establishing occupational exposure limits (OELs) for chemical allergens presents numerous difficulties for occupational hygiene professionals. Few OELs have been developed for LMW allergens because of the unique biological mechanisms that govern the immune-mediated responses. The purpose of this article is to explore the primary challenges confronting the establishment of OELs for LMW allergens. Specific topics include: (1) understanding the biology of LMW chemical allergies as it applies to setting OELs; (2) selecting the appropriate immune-mediated response (i.e., sensitization versus elicitation); (3) characterizing the dose (concentration)-response relationship of immune-mediated responses; (4) determining the impact of temporal exposure patterns (i.e., cumulative versus acute exposures); and (5) understanding the role of individual susceptibility and exposure route. Additional information is presented on the importance of using alternative exposure recommendations and risk management practices, including medical surveillance, to aid in protecting workers from exposures to LMW allergens when OELs cannot be established.

Imaging in occupational and environmental lung disease

PURPOSE OF REVIEW

Work-related and environmental lung disease is increasing over time and new antigens causing pulmonary response are described in medical literature every year with more or less specific imaging findings. The purposes of this review are to highlight the current role of imaging, describe classic as well as uncommon high-resolution computed tomography (HRCT) patterns helpful in guiding diagnosis and update the recent literature on this topic.

RECENT FINDINGS

Recent literature on imaging of occupational and environmental lung disease is scarce and is predominantly based on the HRCT appearance related to specific antigen exposure and on prognostic significance of findings.

SUMMARY

Knowledge of imaging modality potential and radiologic appearance may guide identification, characterization and follow-up of old and new occupational and environmental lung diseases. HRCT plays a key role in this context, having radiation exposure as a major limitation, especially in asymptomatic patients. Low-dose HRCT has the potential to be employed for screening and surveillance of the exposed individuals. However, future research is needed to further this field.

An airborne actinobacteria Nocardiopsis alba isolated from bioaerosol of a mushroom compost facility

Actinobacteria are widely distributed in many environments and represent the most important trigger to the occupant respiratory health. Health complaints, including hypersensitivity pneumonitis of the workers, were recorded in a mushroom compost facility (MCF). The studies on the airborne bacteria were carried out to find a possible microbiological source of these symptoms. Culture analysis of compost bioaerosols collected in different location of the MCF was performed. An assessment of the indoor microbial exposure revealed bacterial flora of bioaerosol in the mushroom compost facility represented by Bacillus, Geobacillus, Micrococcus, Pseudomonas, Staphylococcus spp., and actinobacterial strain with white aerial mycelium. The thermotolerant actinobacterial strain of the same morphology was repeatedly isolated from many locations in MCF: air, compost sample, and solid surface in production hall. On the base of complex morphological, chemotaxonomic, and phylogenetic characteristics, the isolate has been classified as Nocardiopsis alba. Dominant position of N. alba in microbial environment of the mushroom compost facility may represent an indicator microorganism in compost bioaerosol. The bioavailability of N. alba in mushroom compost facility creates potential risk for the health of workers, and the protection of respiratory tract and/or skin is strongly recommended.

TLR2 regulates neutrophil recruitment and cytokine production with minor contributions from TLR9 during hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that develops following repeated exposure to environmental antigens. The disease results in alveolitis, granuloma formation and may progress to a fibrotic chronic form, which is associated with significant morbidity and mortality. The severity of the disease correlates with a neutrophil rich influx and an IL-17 response. We used the Saccharopolysporarectivirgula (SR) model of HP to determine whether Toll-like receptors (TLR) 2 and 9 cooperate in neutrophil recruitment and IL-17-associated cytokine production during the development of HP. Stimulation of bone marrow derived macrophages (BMDMs) from C57BL/6, MyD88^-/- and TLR2/9^-/- mice with SR demonstrate that SR is a strong inducer of neutrophil chemokines and growth factors. The cytokines induced by SR were MyD88-dependent and, of those, most were partially or completely dependent on TLRs 2 and 9. Following in vivo exposure to SR, CXCL2 production and neutrophil recruitment were reduced in TLR2^-/- and TLR2/9^-/- mice suggesting that the response was largely dependent on TLR2; however the reduction was greatest in the TLR2/9^-/- double knockout mice indicating TLR9 may also contribute to the response. There was a reduction in the levels of pro-inflammatory cytokines TNFα and IL-6 as well as CCL3 and CCL4 in the BALF from TLR2/9^-/- mice compared to WT and single knockout (SKO) mice exposed one time to SR. The decrease in neutrophil recruitment and TNFα production in the TLR2/9^-/- mice was maintained throughout 3 weeks of SR exposures in comparison to WT and SKO mice. Both TLRs 2 and 9 contributed to the Th17 response; there was a decrease in Th17 cells and IL-17 mRNA in the TLR2/9^-/- mice in comparison to the WT and SKO mice. Despite the effects on neutrophil recruitment and the IL-17 response, TLR2/9^-/- mice developed granuloma formation similarly to WT and SKO mice suggesting that there are additional mediators and pattern recognition receptors involved in the disease.