Organic dust-induced lung injury and repair: Bi-directional regulation by TNFα and IL-10.

Exposure to organic dust increases chronic airway inflammatory disorders. Effective treatment strategies are lacking. It has been reported that hog barn dust extracts (HDE) induce TNFα through protein kinase C (PKC) activation and that lung inflammation is enhanced in scavenger receptor A (SRA/CD204) knockout (KO) mice following HDE. Because interleukin (IL)-10 production can limit excessive inflammation, it was hypothesized here that HDE-induced IL-10 would require CD204 to effect inflammatory responses. C57BL/6 wild-type (WT), SRA KO, and IL-10 KO mice were intranasally challenged daily for 8 days with HDE and subsequently rested for 3 days with/without recombinant IL-10 (rIL-10) treatment. Primary peritoneal macrophages (PM) and murine alveolar macrophages (MH-S cells) were treated in vitro with HDE, SRA ligand (fucoidan), rIL-10, and/or PKC isoform inhibitors. HDE induced in vivo lung IL-10 in WT, but not SRA KO mice, and similar trends were demonstrated in isolated PM from same treated mice. Lung lymphocyte aggregates and neutrophils were elevated in in vivo HDE-treated SRA and IL-10 KO mice after a 3-d recovery, and treatment during recovery with rIL-10 abrogated these responses. In vitro rIL-10 treatment reduced HDE-stimulated TNFα release in MH-S and WT PM. In SRA KO macrophages, there was reduced IL-10 and PKC zeta (ζ) activity and increased TNFα following in vitro HDE stimulation. Similarly, blocking SRA (24 hr fucoidan pre-treatment) resulted in enhanced HDE-stimulated macrophage TNFα and decreased IL-10 and PKCζ activation. PKCζ inhibitors blocked HDE-stimulated IL-10, but not TNFα. Collectively, HDE stimulates IL-10 by an SRA- and PKCζ-dependent mechanism to regulate TNFα. Enhancing resolution of dust-mediated lung inflammation through targeting IL-10 and/or SRA may represent new approaches to therapeutic interventions.

Enfermedad del pulmón del granjero: análisis de 75 casos / Farmer's lung disease: Analysis of 75 cases

Introducción: La enfermedad del pulmón de granjero (EPG) es una forma frecuente de neumonitis por hipersensibilidad, posiblemente infradiagnosticada. El objetivo de este estudio es describir las características clínicas, la evolución y los factores que influyen en el pronóstico de los pacientes con EPG. Pacientes y métodos: Estudio retrospectivo que incluyó a todos los pacientes diagnosticados de EPG por haber presentado una exposición ambiental de riesgo, una clínica, una función pulmonar y una radiología compatible, en los que se demostró sensibilización antigénica y/o una anatomía patológica concordante. Resultados: Se incluyeron 75 pacientes con EPG, 50 con forma aguda o subaguda (FAS) y 25 con forma crónica (FC). Un 44% de los pacientes (n=33) fue diagnosticado durante los meses de marzo y abril, especialmente aquellos con FAS en comparación con las FC (52 vs. 28%; p=0,0018). En las FAS la DLco presentó una mejoría durante el seguimiento (p=0,047). La determinación de anticuerpos IgG específicos fue positiva en 39 pacientes (78%) con FAS (44% de ellos frente a Aspergillus) y en 12 con FC (48%). La realización de la evitación antigénica (OR 9,26, IC 95% 1,3-66,7, p=0,026) y la administración de tratamiento inmunodepresor (OR 16,13, IC 95% 1,26-200, p=0,033) fueron los factores predictores de mejor evolución de la enfermedad. Conclusiones: La EPG presenta un inicio con predominio estacional en nuestro medio. Las FC presentan habitualmente determinación de anticuerpos IgG específicos negativos, a diferencia de las FAS, donde los anticuerpos frente Aspergillus son las más frecuentes. La evitación antigénica y el tratamiento inmunodepresor son posibles predictores de mejor evolución de la enfermedad (AU)

Introduction: Farmer's lung disease (FLD) is a common form of hypersensitivity pneumonitis possibly underdiagnosed in our midst. The aim of this study was to describe clinical characteristics, evolution and factors that influence the prognosis of patients with FLD. Patients and methods: A retrospective study that included all patients diagnosed with FLD presenting an environmental exposure risk, a clinic, lung function and a compatible radiology, in which antigen sensitisation was demonstrated and/or a concordant pathology. Results: We selected 75 patients with FLD, 50 with acute or subacute form (ASF) and 25 with chronic form (CF). Forty-four percent of patients (n=33) were diagnosed during the months of March and April, especially those with ASF compared to CF (52 vs. 28%; P=.0018). In the ASF group, DLco showed an improvement during follow-up (P=.047). The determination of specific IgG antibodies was positive in 39 patients (78%) with ASF (44% of them against Aspergillus) and CF 12 (48%). The realisation of antigenic avoidance (OR 9.26, 95% CI 1.3-66.7, P=.026) and the administration of immunosuppressive therapy (OR 16.13, 95% CI 1.26-200, P=.033) were predictors of better disease progression. Conclusions: FLD is predominantly seasonal in our environment. CF usually has a negative specific IgG antibodies unlike ASF, where antibodies against Aspergillus are the most common. The realisation of antigenic avoidance and immunosuppressive treatment are possible predictors of better disease progression (AU)

Characterization of the lung epithelium of wild-type and TLR9(-/-) mice after single and repeated exposures to chicken barn air.

Exposure to chicken barn air causes lung injury resulting in lower and upper respiratory symptoms in the poultry workers, and mechanisms of which are not fully understood. The lung injury can initiate modifications such as proliferation of the airway epithelial cells such as Clara cells, type II alveolar (T2) cells and mucus producing goblet cells as part of the innate immune response. Toll-like receptors (TLR) have been suggested to play a role in cell division and proliferation. To understand the effect of TLR9 on Clara cells, T2 and mucus-producing goblet cells, we quantified the numbers of these cells in the lungs of wild-type (WT) and TLR9(-/-) mice exposed to chicken barn air. The mice were exposed for either one day or five or 20 days for 8 h/day. Clara cells and T2 cells were labelled with antibodies, and the mucus cells were identified with Periodic-acid Schiff stain, and quantified in per unit tissue section area. The data show decrease in the number of Clara cells and increase in mucus-producing goblet cells after exposure to chicken barn air in both WT and TLR9(-/-) mice. Numbers of T2 cells increased and decreased in WT and TLR9(-/-) mice, respectively, after exposure to poultry barn air. These data show that exposure to chicken barn air can affect major lung epithelial cells, and allude to the role of TLR9 in regulation of some of these responses.

Farmer's lung in a case after bullectomy.

We present a case of farmer's lung (FL) with the primary presenting feature of a large bulla in the lung. A 70-year-old nonsmoking woman with dyspnea on exercise was referred for surgical resection of a large bulla in the lung. The postoperative evaluation of the lung tissue revealed a follicular lymphocytic alveolitis and loosely formed granulomas suspicious for hypersensitivity pneumonitis (HP). The patient had worked in farming since her youth. Dyspnea on exercise was the only symptom, but it was related to the large bulla. No other radiologic features of HP were shown in a high-resolution CT of the lung. Specific IgG antibodies against typical antigens of FL were detected, bronchoalveolar lavage demonstrated no lymphocytic alveolitis but an inhalative challenge with own hay was positive. A diagnosis of chronic FL was made. Despite lung emphysema being a possible reaction in FL, giant bullae as primary and single manifestation of this disease have not been reported before.

Hypersensitivity pneumonitis caused by fungi.

Hypersensitivity pneumonitis (HP) is a complex syndrome caused by an exaggerated immune response to the inhalation of a large variety of organic particles. The most frequent antigens that cause HP worldwide are bird proteins (pigeon breeders' disease) and bacteria (Saccharopolyspora rectivirgula). However, fungi are also implicated in many cases, including occupational and nonoccupational outbreaks. The clinical course of the disease is highly variable and its diagnosis clinically challenging since no specific test or biomarker allows a consistent diagnosis. Therefore, a combination of symptoms, bronchoalveolar lavage findings, chest imaging, lab tests, and often biopsies are needed for an accurate diagnosis. Regardless of the cause or the responsible environment, the histopathology is similar and usually consists of a granulomatous interstitial bronchiolocentric pneumonitis characterized by the presence of poorly formed granulomas and a prominent interstitial infiltrate composed of lymphocytes, plasma cells, and macrophages. However, some patients may show a "nonspecific interstitial pneumonia" pattern, or even a usual interstitial pneumonia-like pattern. Importantly, patients with chronic HP may evolve to interstitial fibrosis or develop emphysematous changes, although the reason(s) for these different pathological responses are presently unclear. This review provides a general overview of HP, emphasizing its fungal etiologies, and also examines the currently used clinical criteria for diagnosis and proposes an alternative classification. Challenges for future research include identification of biomarkers that may predict outcome and progression (primarily of chronic HP), and the need for a better understanding of the underlying molecular and genetic mechanisms of the disease.

Protein kinase D1 is essential for the proinflammatory response induced by hypersensitivity pneumonitis-causing thermophilic actinomycetes Saccharopolyspora rectivirgula.

Hypersensitivity pneumonitis is an interstitial lung disease that results from repeated pulmonary exposure to various organic Ags, including Saccharopolyspora rectivirgula, the causative agent of farmer's lung disease. Although the contributions of proinflammatory mediators to the disease pathogenesis are relatively well documented, the mechanism(s) involved in the initiation of proinflammatory responses against the causative microorganisms and the contribution of signaling molecules involved in the host immune defense have not been fully elucidated. In the current study, we found that S. rectivirgula induces the activation of protein kinase D (PKD)1 in lung cells in vitro and in vivo. Activation of PKD1 by S. rectivirgula was dependent on MyD88. Inhibition of PKD by pharmacological PKD inhibitor Gö6976 and silencing of PKD1 expression by small interfering RNA revealed that PKD1 is indispensable for S. rectivirgula-mediated activation of MAPKs and NF-kappaB and the expression of various proinflammatory cytokines and chemokines. In addition, compared with controls, mice pretreated with Gö6976 showed significantly suppressed alveolitis and neutrophil influx in bronchial alveolar lavage fluid and interstitial lung tissue, as well as substantially decreased myeloperoxidase activity in the lung after pulmonary exposure to S. rectivirgula. These results demonstrate that PKD1 is essential for S. rectivirgula-mediated proinflammatory immune responses and neutrophil influx in the lung. Our findings also imply the possibility that PKD1 is one of the critical factors that play a regulatory role in the development of hypersensitivity pneumonitis caused by microbial Ags and that inhibition of PKD1 activation could be an effective way to control microbial Ag-induced hypersensitivity pneumonitis.

[Farmer's lung disease caused by straw or hay? Case report]. / Hálmsótt eda heysótt?

A young woman was admitted to Akranes Regional Hospital because of dyspnea, fatigue and fever. She was found to have bilateral pneumonia but etiology was not found. She was treated with antibiotics with good resolution and was discharged after eight days from the hospital. Four weeks later she noticed rapidly progressive dyspnea and was found to be hypoxemic, and to have restrictive spirometry and diffuse interstitial changes on chest radiography. Computerized tomography of the lungs showed diffuse ground glass changes. Transbronchial biopsies from the lungs showed numerous small granulomas. She was treated with prednisolone for a short time with excellent recovery. She stall-fed horses and underneath them was straw containing organic dust. This is important to keep in mind as a differential diagnosis to farmers lung disease that is caused by hay.

Role of interleukin-2 in the development and persistence of lymphocytic alveolitis in farmer's lung.

Farmer's lung (FL) is characterized by an intense lymphocytic alveolitis which persists after an acute episode with continuous exposure to the offending antigens. This study aimed to examine the role of interleukin-2 (IL-2) in the development and persistence of this lymphocytic alveolitis. Three groups of dairy farmers were studied: acute FL, ex-FL (past history of FL but no clinical evidence of active disease) and asymptomatic farmers (no lung disease). IL-2 was measured by enzyme immunosorbent assay and T-cell proliferation was evaluated by 3H-thymidine incorporation. Acute and ex-FL patients had more lymphocytes (p<0.01) and higher levels of IL-2 (p<0.05) in their bronchoalveolar lavage (BAL) than asymptomatic farmers. BAL T-lymphocytes from acute and ex-FL patients released considerable amounts of IL-2 after stimulation with concanavalin A and showed dose-dependent proliferative responses to IL-2. IL-2 production was decreased after treatment with prednisone. Acute FL patients, but not ex-FL, had higher levels of soluble CD25 in their serum than asymptomatics (p=0.009). These results suggest that interleukin-2 may play a role in farmer's lung by providing a stimulus not only for the accumulation of lymphocytes but also for their persistence at the site of hypersensitivity reaction, and that the lung is a likely source of this cytokine in vivo.

TNF receptor-deficient mice reveal divergent roles for p55 and p75 in several models of inflammation.

The pleiotropic activities of the potent proinflammatory cytokine TNF are mediated by two structurally related, but functionally distinct, receptors, p55 and p75, that are coexpressed on most cell types. The majority of biologic responses classically attributed to TNF are mediated by p55. In contrast, p75 has been proposed to function as both a TNF antagonist by neutralizing TNF and as a TNF agonist by facilitating the interaction between TNF and p55 at the cell surface. We have examined the roles of p55 and p75 in mediating and modulating the activity of TNF in vivo by generating and examining mice genetically deficient in these receptors. Selective deficits in several host defense and inflammatory responses are observed in mice lacking p55 or both p55 and p75, but not in mice lacking p75. In these models, the activity of p55 is not impaired by the absence of p75, arguing against a physiologic role for p75 as an essential element of p55-mediated signaling. In contrast, exacerbated pulmonary inflammation and dramatically increased endotoxin induced serum TNF levels in mice lacking p75 suggest a dominant role for p75 in suppressing TNF-mediated inflammatory responses. In summary, these data help clarify the biologic roles of p55 and p75 in mediating and modulating the biologic activity of TNF and provide genetic evidence for an antagonistic role of p75 in vivo.

Diagnostic accuracy of transbronchial biopsy in acute farmer's lung disease.

STUDY OBJECTIVES: To evaluate whether transbronchial biopsy (TBB) is useful for the diagnosis of acute farmer's lung (FL) by calculating the likelihood ratios (LHRs) of (1) simple pathologic criteria and (2) an overall assessment of the biopsy specimens. DESIGN: Retrospective study in which a blinded analysis of 105 TBBs with adequate material from patients with parenchymal diseases (55 cases of FL matched with 50 control samples) was performed by two independent pathologists. SETTING: Respiratory clinic of a university-affiliated referral center. MEASUREMENTS: Three pathologic criteria were first studied: (1) diffuse lymphocytic infiltration (LI); (2) focal LI; and (3) granulomas. Then, an overall assessment or the TBB was done. Four diagnostic categories were considered: (1) probable FL; (2) possible FL; (3) nonspecific; and (4) alternative diagnosis. LHRs favoring the diagnosis of FL were calculated for the pathologic criteria and for each diagnostic category. RESULTS: For both the pathologic criteria and the overall assessments, the interobserver agreement was fair. As a pathologic criterion, "diffuse LI" was better than "loosely formed granuloma" to discriminate FL from control samples (LHR, 9.1 [confidence interval, 2.2 to 37.0] vs 1.8 [confidence interval, 0.5 to 6.9]). After the overall assessment, as many as 48.6% of the TBBs were read as nonspecific. The LHRs of the four diagnostic categories were as follows: (1) probable FL: 1.1 (observer 1) and 2.6 (observer 2); (2) possible FL: 2.2 and 1.7; (3) nonspecific: 0.9 and 0.6; and (4) alternative diagnosis: 0.4 and 0.0. CONCLUSION: Hematoxylin-eosin-stained TBB specimen is of limited usefulness for the diagnosis of FL and should be reserved for patients with intermediate pretest probability of FL. Diffuse LI best discriminates FL from control samples and should be specifically sought.

Th1 CD4+ cells adoptively transfer experimental hypersensitivity pneumonitis.

Cultured cells from Micropolyspora faeni-sensitized donors can adoptively transfer murine experimental hypersensitivity pneumonitis (EHP). To determine whether the CD4+ cells responsible for transfer have characteristics of Th1 or Th2 cells, we established cell lines from lung-associated lymph nodes of M. faeni-sensitized C3H/HeJ mice by culturing with antigen and either IFN-gamma, IL2, and anti-IL4, or IL4. Cell lines were stimulated regularly with antigen, fresh antigen-presenting cells, and the cytokine/anti-cytokine antibody cocktail. At various times after initiation of culture, cells were injected intravenously into recipients, which were then challenged intratracheally with M. faeni and sacrificed and the extent of pulmonary inflammatory response was determined. IFN-gamma, IL4, and IL10 levels were determined in supernatants of cell cultures stimulated with M. faeni to characterize the cell lines as Th1 (IFN-gamma, but low IL4 and IL10 secretion) or Th2 (IL4 and IL10, but low IFN-gamma secretion). Cell lines were differentiated into either Th1 (IFN-gamma = 310 +/- 45 U/ml, IL4 = 0.10 +/- 0.1 U/ml, IL10 = 1750 +/- 75 pg/ ml, >99% CD4+) cell lines by Day 16 of culture or Th2 cell lines (IFN-gamma = 1.8 +/- 1.0 U/ml, IL4 = 830 +/- 388 U/ml, IL10 = 51,700 +/- 10,900 pg/ml, >96% CD4+) by Day 30. Th1 cell lines were able to adoptively transfer EHP whereas Th2 cell lines were unable to adoptively transfer EHP. The ability to transfer EHP was directly related to the amount of IFN-gamma and inversely to the amount of IL4 secreted by antigen-stimulated cells. We conclude that it is possible to produce CD4+ cell lines with either Th1 or Th2 characteristics from lung-associated lymph nodes of mice exposed to M. faeni and that only Th1 CD4+ cell lines can adoptively transfer EHP.

Elafin/elastase-specific inhibitor in bronchoalveolar lavage of normal subjects and farmer's lung.

Secretory leukocyte proteinase inhibitor (SLPI) and alpha1-proteinase inhibitor (alpha1(PI)) cannot fully explain the total neutrophil elastase (NE) inhibitory capacity detected in bronchoalveolar lavage (BAL) fluid, suggesting the existence of other NE inhibitor(s). In the present study, we measured the concentrations of elafin, a newly described, low-molecular-weight serine proteinase inhibitor, SLPI, and alpha1(PI) in BAL fluids from eight healthy subjects, 13 asymptomatic farmers, seven farmers with active farmer's lung (FL), and seven farmers with previous (Ex) FL. In addition to SLPI and alpha1(PI), elafin was present in BAL fluids from control subjects and asymptomatic farmers, 13 (7-31) and 12 (7-67) mmol/mol of albumin (median and range) respectively. Elafin concentration increased significantly to 105 (38-207) mmol/mol of albumin in farmers with active FL and was also elevated in farmers with Ex FL. Elafin levels were highly correlated with lung inflammatory cell numbers, especially lymphocytes, and the decrease in single-breath diffusion capacity (DLCO). Elafin and SLPI were linked to yet uncharacterized proteins in BAL fluids. In conclusion, elafin is a constituent of BAL fluid from normal subjects and is found in enhanced concentrations in FL and in farmers with lymphocytic alveolitis. This suggests that elafin may play a role in lung homeostasis and inflammation.

Mast cell and histamine involvement in farmer's lung disease.

The aim of this study was to evaluate the cellular and biochemical characteristics of the bronchoalveolar lavage (BAL) fluid in patients with farmer's lung disease (FLD). Total cell numbers in BAL fluids from patients with FLD (n = 30) were significantly higher than in normal subjects (n = 7; p < 0.01), and differential cell counts were significantly different. Lymphocytes were the most numerous cell type in BAL fluids from patients with FLD (65.4 +/- 2.5 percent vs 6.8 +/- 0.5 percent), and analysis of lymphocyte subsets revealed increased percentages of CD3+ and CD8+ cells (91.8 +/- 0.9 percent vs 68.8 +/- 3 percent, p < 0.01, and 54.3 +/- 3.1 percent vs 30.1 +/- 3.2 percent, p < 0.01, respectively). A marked increase in mast cell numbers, as revealed by the specific alcian blue/safranin staining, was observed in patients with FLD (4.2 +/- 0.57 percent, n = 12, vs 0.18 +/- 0.04 percent, n = 7, p < 0.001). Histamine levels in BAL supernatants were increased in patients with FLD (mean = SEM, 4.4 +/- 0.8 ng/ml vs 0.9 +/- 0.1 ng/ml; median, 2.4 ng/ml vs 0.9 ng/ml, p < 0.01), and correlated positively with mast cell numbers and percentages (r = +0.63, p < 0.03, and r = +0.69, p < 0.02, respectively); conversely, a negative correlation was found between histamine levels and CD8+ lymphocyte percentages (r = -0.48, p < 0.01). Raised neutrophil percentages (5.1 +/- 0.8 vs 0.5 +/- 0.18, p < 0.05) and albumin concentrations (29.2 +/- 3.9 mg/dl vs 3.4 +/- 1.3 mg/dl, p < 0.01) were also found in patients with FLD. These findings show that increased numbers of mast cells, lymphocytes, and neutrophils can be found in BAL fluids of patients with FLD. The increased histamine levels in the supernatants of BAL fluids indicate that mast cells are activated. These data allow us to postulate a role for mast cell accumulation and histamine release in the inflammatory process of FLD.

Mast cells in fibrotic lung disorders.

Fibrotic lung disorders are chronic inflammatory diseases in which inflammatory processes in the lower respiratory tract injure the lung and modulate the proliferation of mesenchymal cells that form the basis of the fibrotic scar. The pathogenesis of fibrosis in fibrotic lung disorders remains unclear; however, recent attention has focused on the potential role of the mast cell in the genesis of fibrosis. To determine whether mast cells are implicated in the pathogenesis of lung fibrosis, mast cells were compared with the degree of fibrosis in transbronchial lung biopsy specimens from 49 patients with fibrotic lung disorders (16 sarcoidosis, 15 farmer's lung disease, 9 cryptogenic fibrosing alveolitis, 6 bronchiolitis obliterans organizing pneumonia, 3 histiocytosis X). In lung tissue of patients with fibrotic lung disorders, there was an increased number of mast cells in respect to the control group (98.6 +/- 7.7 vs 27.8 +/- 5.1 mast cells per square millimeter, p < 0.01). Mast cell counts in lung biopsy specimens were significantly correlated with the degree of fibrosis (r = 0.87, p < 0.001); 80.8 percent of mast cells were found in the alveolar septa, 9.6 percent within alveoli, 1.9 percent among alveolar lining cells, and 5 percent along blood vessels. No mast cells were located within alveoli in controls. Our data suggest that mast cells participate in chronic inflammation and that their presence is related to interstitial fibrosis in a much broader spectrum of fibrotic lung disorders.

Farmer's fever. Systemic manifestation of farmer's lung without lung involvement.

A 35-year-old dairy farmer presented with recurrent febrile episodes over more than three years. Fever up to 39 degrees C occurred only if he was in contact with the dairy barn and typically appeared at 4 to 8 h after an otherwise usual barn exposure. He had no dyspnea and throughout this period repeated physical examinations, chest roentgenograms, and lung functions remained normal. He was bronchoscoped and lavaged on three occasions, a lymphocytic alveolitis was always present and once, immediately after an acute episode, an important increase in lavage neutrophils was also found (47 percent). Transbronchial lung biopsy specimens showed a moderate cellular infiltrate but no granuloma or fibrosis. Three other persons who worked at the same farm had no similar manifestations or respiratory illnesses. The patient therefore had typical systemic manifestations of acute farmer's lung, but without the lung involvement required to confirm that diagnosis. Furthermore, his disease does not fit the entities known as grain fever and organic dust toxic syndrome. We believe that this patient presented a different entity that we coined "farmer's fever."

[Experimental studies of lung lesions in rabbits caused by Streptomyces thermohygroscopicus].

Imitating the natural way of infection of Farmer's lung disease, we succeeded in inducing acute lesions of Farmer's lung disease in rabbits by the dry powder of thermohygroscopicus. Histopathological examination revealed typical interstitial pneumonitis, alveolitis and bronchiolitis. One week after the inhalation of the dry powder of thermohygroscopicus, the precipitins could be detected in the rabbits' serum by immunoblotting. Depending on the lung lesions of rabbits, we discussed the pathogenetic mechanisms of Farmer's Lung.

Hyaluronic acid (hyaluronan) in BAL fluid distinguishes farmers with allergic alveolitis from farmers with asymptomatic alveolitis.

Pulmonary function measurements, bronchoalveolar lavage (BAL), and analyses of precipitating antibodies in blood were performed in 12 farmers wtih no symptoms from the airways and 12 farmers who were admitted to the hospital due to acute symptoms of alveolitis (all nonsmokers). In addition, a bronchial methacholine provocation test was performed in the asymptomatic farmers. In 11 of the 12 symptomatic farmers but in none of the asymptomatic farmers, precipitating antibodies against one or more of the microorganisms which usually occur in a farmer's environment were found. In the farmers with symptomatic alveolitis, a restrictive impairment of pulmonary function was found, while pulmonary function was normal in all asymptomatic farmers. Findings in the BAL fluid showed increased concentrations of total cells, lymphocytes, and neutrophils and elevated levels of albumin, fibronectin, and angiotensin-converting enzyme in asymptomatic farmers compared with our own reference group. The same analyses in BAL fluid from the symptomatic farmers revealed a further increase in all parameters compared with the asymptomatic farmers. The BAL fluid from asymptomatic farmers had normal levels of hyaluronic acid (hyaluronan) and procollagen 3 N-terminal peptide, while these levels were significantly increased in the symptomatic group. We conclude that inflammation in the alveolar space and signs of activation of alveolar macrophages are present in farmers regardless of respiratory symptoms, although these findings are more pronounced in the presence of symptoms of acute alveolitis; however, the findings of impaired pulmonary function and the occurrence of precipitins and elevated levels of hyaluronic acid and procollagen 3 N-terminal peptide in BAL fluid were exclusively found in the farmers with airways symptoms. We postulate the hyaluronic acid, due to its pronounced ability to immobilize water, may be of importance in the development of the pulmonary function impairment observed in farmer's lung disease.

Complete clarification of a case of farmer's lung.

The diagnostic curriculum to clarify a case of farmer's lung in a fibrotic stage is presented, including clinical functional tests, X-ray, analysis of cellular elements recovered from bronchioalveolar lavage, determination of precipitating antibodies in the circulation, histological and immunohistological studies of transbronchial lung biopsies. The patient had precipitating antibodies against several species of hay molds, especially Micropolyspora faeni, and immune complex deposition in the lung. Elution experiments on frozen sections of the lung biopsies and subsequent administration of patient's serum- or mold antigen-specific antibodies combined with appropriate serum absorption experiments allowed the identification of the relevant antigen, i.e. M. faeni, in the deposited immune complexes. The immunohistological analysis of extracellular matrix components revealed an interstitial increase in procollagen and collagen type I and an even more pronounced augmentation of procollagen type III and fibronectin, i.e. a constellation characteristic for a chronic, active lung fibrosis that developed on the basis of an immune complex disease.

Mast cells in bronchoalveolar lavage fluid and in transbronchial biopsy specimens of patients with farmer's lung disease.

Recently, an increased number of mast cells have been reported in bronchoalveolar lavage fluid (BAL) of patients with farmer's lung disease. Some authors pointed out the pathogenetic importance of mast cells in farmer's lung on the basis of their correlation with the activity of the disease, with the BAL lymphocyte counts, and with the markers of lung fibrosis. To determine whether BAL reflects the histologic aspects of the lung histologic features in patients with farmer's lung disease, mast cells recovered from lavage fluid were compared with tissue sections from transbronchial lung biopsies in 15 patients. Mast cell counts in BAL and lung biopsy specimens were significantly correlated (r = 0.88; p less than 0.01), while no other correlations between BAL inflammatory cells and tissue mast cells were found. In lung tissue, there were four times the increased number of mast cells in respect to the control group (84.4 +/- 28.8 vs 20.4 +/- 13.4 mast cells per square millimeter); 83.2 percent of mast cells were found in the alveolar septa, 14.9 percent within alveoli, 0.7 percent among alveolar lining cells, and 1 percent along blood vessels. No mast cells were located within alveoli in controls. In BAL, only lymphocyte and mast cell counts (56.4 +/- 18.6 percent, p less than 0.001; 3.9 +/- 1.5 5 percent, p less than 0.001, respectively) were significantly increased. Our data suggest that in farmer's lung disease, BAL correctly samples the alveolitis. Mast cells, such as lymphocytes, seem to be primary inflammatory cells involved at the site of the disease activity.