The role of interleukin-8 in interstitial pneumonia

OBJECTIVE: A variety of inflammatory cells accumulate in the lungs of patients with interstitial lung disease. The potential for IL-8 to be released from these cells into the lungs of patients with idiopathic interstitial pneumonia (IIP), interstitial pneumonia with collagen vascular disease (IP-CVD), sarcoidosis (SAR) and hypersensitivity pneumonitis (HP) was investigated. METHODOLOGY: IL-8 levels were assessed by enzyme-linked immunosorbent assay in BAL fluid and serum, and the expression of IL-8 in the lungs of these patients was evaluated by immunohistochemistry. RESULTS: Serum IL-8 levels were significantly elevated in patients with IIP (P < 0.05) and SAR (P < 0.01). In BAL fluid, the IL-8 level was significantly higher in patients with IIP (P < 0.05), IP-CVD (P < 0.01), SAR (P < 0.01) and HP (P < 0.01). In several cases, IL-8 level correlated with neutrophil density. The IL-8 immunopositive cells were type II pulmonary epithelial cells and alveolar and interstitial macrophages in patients with IIP and IP-CVD. CONCLUSIONS: IL-8 is likely to be a key factor in the pathogenesis of fibrosis of the lung and in lung injury.     

Alveolar macrophages from bronchoalveolar lavage of patients with pulmonary histiocytosis X: Determination of phenotypic and functional changes

In recent years the alveolar macrophage has been found to play a central role in interstitial lung disease. Pulmonary histiocytosis X is characterized by infiltrating fibroblasts, mononuclear cells, and CD-1-positive Langerhans cells. Bronchoalveolar lavage (BAL) fluid displays an increase of CD-1-positive cells and a remarkable exaggeration of the total cell count with only slight changes in the differential cell count. Changes of alveolar macrophage phenotype and functional activity occurring in pulmonary histiocytosis X have not yet been characterized. The BAL fluid of nine patients with histologically proven isolated pulmonary histiocytosis X was compared with that of 16 control patients. Immunophenotyping of alveolar macrophages by monoclonal maturation and differentiation markers of monocyte/ macrophage lineage cells [Ki-M2, Ki-M6 (CD-68), Ki-M8, Ki-M1 (CD- 11c)] revealed a significant increase of immature macrophages with a more monocyte-like phenotype. The proliferation marker Ki-67 revealed an increased proportion of proliferating macrophages. Functional analysis by measuring oxygen radical release revealed an increase both in baseline and stimulated luminol-enhanced chemiluminescence. Fibronectin production was elevated in alveolar macrophage supernatants from pulmonary histiocytosis X patients. These findings are consistent with phenotypic changes of alveolar macrophages in other interstitial lung diseases such as sarcoidosis and idiopathic pulmonary fibrosis. Local proliferation and the fresh influx of blood monocytes seem to be responsible for the increase in immature and functionally activated alveolar macrophages. The increase in oxygen radical release and fibronectin production suggests an augmented tissue injuring and fibrosing capacity of alveolar macrophages in pulmonary histiocytosis X.     

C5 contents and neutrophil chemotactic activities in bronchiolar and alveolar regions

To clarify the localization and mechanism of neutrophil infiltration in the lower respiratory tract, we measured neutrophil number, neutrophil chemotactic factor (NCF) activity and content of C5 in bronchial lavage (BL) fluid and bronchoalveolar lavage (BAL) fluid. Numbers of neutrophils, NCF activity and C5 content were higher in the BL fluid from normal volunteers (NV) and control patients (CP) than those in the BAL fluid from the same subjects. The NCF activity in the BL fluid was inhibited approximately 40% by anti-C5 antiserum, and correlated with C5 content in the BL fluid. In the BAL fluids of patients with chronic airway diseases (CAD) and patients with idiopathic interstitial pneumonia (IIP), neutrophil number, NCF activity and C5 content were increased compared to those in BAL fluid from NV or CP. These results indicated that neutrophils are predominant in the bronchial region compared to the alveolar region, and that C5-derived NCF play important roles in the accumulation of neutrophils in the bronchial region. Also C5-derived NCF are thought to be related to, at least, a part of the neutrophil infiltration in the respiratory tract of patients with CAD and IIP.     

Cockade-like structures in alveolar macrophages in extrinsic allergic alveolitis

BACKGROUND AND OBJECTIVES: In immunocytochemical preparations of bronchoalveolar lavage (BAL) cells from patients with extrinsic allergic alveolitis (EAA), we observed the presence of alveolar macrophages with cockade-like structures in their cytoplasm (cockade+ alveolar macrophages). These cockade+ alveolar macrophages may reflect a subpopulation of alveolar macrophages which may show a different predominance in various interstitial lung diseases. In this study we aimed to compare the frequency of cockade+ alveolar macrophages in patients with EAA (n = 14) with the results obtained in patients with sarcoidosis (n = 11), idiopathic interstitial pneumonia (IIP; n = 10) and control subjects (n = 8). We also investigated the expression of the transferrin receptor CD71 on cockade+ alveolar macrophages. METHODS: In BAL fluid, the total number of cells and differential counts were determined, and immunocytologic examinations of macrophages and lymphocytes were done using monoclonal antibodies. The percentage of cockade+ alveolar macrophages was determined by counting 300 macrophages in the CD20 field of an immunocytochemical slide. RESULTS: The percentage of cockade+ alveolar macrophages was significantly higher in the EAA group (36 +/- 9%) compared to patients with sarcoidosis (12 +/- 5%) or IIP (11 +/- 10%) and control subjects (3 +/- 1%; p < 0.001). The proportion of CD71+ alveolar macrophages was significantly lower in EAA than in the other groups (p < 0.01), and the CD71 antigen was expressed on a significantly lower proportion of cockade+ alveolar macrophages compared to cockade- alveolar macrophages in EAA (p < 0.001). CONCLUSION: We conclude that cockade+ alveolar macrophages could play a role in the pathogenesis and differential diagnosis EAA.     

Bronchoalveolar lavage in idiopathic interstitial lung diseases

Bronchoalveolar lavage (BAL) is useful for diagnosing various interstitial lung diseases (ILDs) and monitoring ILD during treatment. The ability to detect specific agents or substances by using BAL is especially helpful in determining whether idiopathic ILD has a background causality. BAL in combination with other intensive examinations may enable the definitive diagnosis of an idiopathic ILD. Among the idiopathic ILDs of concern, this article focuses on idiopathic interstitial pneumonia (IIP) and cryptogenic organizing pneumonia (COP). IIP and COP are classified together as idiopathic interstitial pneumonia (IIP), an integrated clinicoradiographic pathological disease entity. BAL has identified two points important for differentiating the disease entity: a paucity of lymphocytes appears in the BAL fluid of patients with idiopathic pulmonary fibrosis (IPF), and lymphocytosis with a decreased CD4:CD8 ratio appears in patients with COP. These findings can be useful, in combination with high-resolution computed tomographic (HRCT) data, for selecting a favorable treatment option. On the other hand, these rules cannot be applied to IP associated with collagen vascular disease (CVD). Furthermore, some IIP patients may manifest features of CVD during the clinical course after the detection of IP (interstitial pneumonia). Thus the definite role of BAL cell profiles remains to be determined.     

Production of fibronectin by the human alveolar macrophage: mechanism for the recruitment of fibroblasts to sites of tissue injury in interstitial lung diseases.

Because cells of the mononuclear phagocyte system are known to produce fibronectin and because alveolar macrophages are activated in many interstitial lung diseases, the present study was designed to evaluate a role for the alveolar macrophage as a source of the increased levels of fibronectin found in the lower respiratory tract in interstitial lung diseases and to determine if such fibronectin might contribute to the development of the fibrosis found in these disorders by being a chemoattractant for human lung fibroblasts. Production of fibronectin by human alveolar macrophages obtained by bronchoalveolar lavage and maintained in short-term culture in serum-free conditions was demonstrated; de novo synthesis was confirmed by the incorporation of [14C]proline. This fibronectin had a monomer molecular weight of 220,000 and was antigenically similar to plasma fibronectin. Macrophages from patients with idiopathic pulmonary fibrosis produced fibronectin at a rate 20 times higher than did normal macrophages; macrophages from patients with pulmonary sarcoidosis produced fibronectin at 10 times the normal rate. Macrophages from 6 of 10 patients with various other interstitial disorders produced fibronectin at rates greater than the rate of highest normal control. Human alveolar macrophage fibronectin was chemotactic for human lung fibroblasts, suggesting a functional role for this fibronectin in the derangement of the alveolar structures that is characteristic of these disorders.     

High-BAL fluid concentrations of RANTES in nonspecific interstitial pneumonia compared with usual interstitial pneumonia

Chemokines such as regulated on activation, normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)-1, monocyte inflammatory protein (MIP)-lalpha have been reported to play an important role in the pathogenesis of interstitial lung diseases. Among idiopathic interstitial pneumonia (IIP), nonspecific interstitial pneumonia (NSIP) has elevated percentages of Lymphocytes in bronchoalveolar lavage (BAL) fluid compared with usual interstitial pneumonia (UIP). These chemokines are candidate mediators for lymphocyte attraction to the lung in NSIR Therefore, we measured the BAL fluid levels of RANTES, MCP-1 and MIP1-alpha in 15 patients with idiopathic NSIP, 20 with idiopathic UIP, 22 with sarcoidosis and 12 healthy volunteers to evaluate the contribution of these chemokines using enzyme-linked immunosorbent assays. The levels of RANTES in BAL fluid were significantly higher in patients with NSIP compared with healthy volunteers (P < 0.01), UIP and sarcoidosis (P < 0.05). In MCP-1, the levels in BAL fluid of NSIP and UIP patients were significantly elevated compared with healthy volunteers and sarcoidosis patients (P < 0.01). These results suggest that RANTES and MCP-1 in BAL fluid may play an important role in inflammatory cell recruitment to the lung in idiopathic NSIP as well as other interstitial lung diseases.     

Neutrophilic alveolitis in idiopathic pulmonary fibrosis. The role of interleukin-8.

Idiopathic pulmonary fibrosis is an immunologically mediated pulmonary disorder in which activated alveolar macrophages (AM) and neutrophils play cardinal roles in the pathogenesis of the inflammatory lung lesion. The factors responsible for the induction and perpetuation of the neutrophilic alveolitis are not known. Recently, a novel cytokine (Interleukin-8) was described that is released by activated mononuclear phagocytes and a variety of other cell types, and it exhibits potent chemotactic activity for polymorphonuclear leukocytes (PMN). Increased expression of IL-8 has been described in other inflammatory disorders characterized by neutrophilic infiltration, including psoriasis, rheumatoid arthritis, and the sepsis syndrome, but no studies have assessed this cytokine in the context of interstitial pulmonary disorders. We have previously shown that normal human AM release IL-8 upon appropriate stimulation, but data assessing the expression of IL-8 by human AM in specific pulmonary disease states are lacking. In this study, we examined the expression of steady-state mRNA for IL-8 by human alveolar macrophages obtained by bronchoalveolar lavage (BAL) from patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis and from healthy volunteers. Because it is known that adherence to plastic culture plates may up-regulate gene expression for IL-8 in the absence of additional stimulation, we extracted mRNA immediately from the cell pellet obtained by BAL rather than using cultured alveolar macrophage monolayers. Northern blot analysis was performed to determine IL-8 mRNA expression. We found that BAL cells from patients with IPF constitutively expressed mRNA for IL-8, and the amount of IL-8 mRNA (as assessed by laser densitometry) correlated with the percent of neutrophils on BAL.(ABSTRACT TRUNCATED AT 250 WORDS)     

Is Metalloproteinase-7 Specific for Idiopathic Pulmonary Fibrosis?

BACKGROUND: Matrix metalloproteinase (MMP)-7 was reported to be a key molecule in the pathogenesis of idiopathic pulmonary fibrosis (IPF) based on the result of microarray analysis and knockout mice. However, the role of MMP-7 has not been determined in other types of idiopathic interstitial pneumonia (IIP). The aim of this study was to investigate the role of MMP-7 in IIP by comparing its expression in usual interstitial pneumonia (UIP) and cryptogenic organizing pneumonia (COP). METHODS: Levels of MMP and tissue inhibitors of metalloproteinase in BAL fluid and their expression on lung tissues were compared between normal control subjects (n = 5) and the patients with IPF (n = 6) and COP (n = 11). RESULTS: There was no significant difference in BAL fluid MMP-7 levels between UIP and COP, although it was higher in both diseases compared to normal control subjects. Furthermore, the pattern and the degree of MMP-7 expression in lung tissues were also similar in both IPF and COP, whereas MMP-2 level was higher in COP and MMP-9 level was higher in IPF. CONCLUSION: MMP-7 seems to play an important role in the pathogenesis of not only IPF but also COP; therefore, it may not be the key factor determining the prognosis or reversibility of IIPs.     

Phenotypic and functional activation of alveolar macrophages,T lymphocytes and NK cells in patients with systemic sclerosis and primary Sj?gren's syndrome.

OBJECTIVES--Attempts to differentiate between the pathogenesis of the severe pulmonary manifestations observed in systemic sclerosis (SSc) and the mild form in primary Sjögren's syndrome (pSS) were performed by studying cell populations recovered during bronchoalveolar lavage (BAL). METHODS AND RESULTS--Two-colour flow cytometric analysis of BAL fluid lymphocytes showed a similar degree of phenotypic activation (DR+) of CD4+ and CD8+ T lymphocyte subsets and CD16+ NK cells in patients with SSc (n = 13) and pSS (n = 11) groups and healthy controls (n = 11). Alveolar macrophages expressed the CD14 antigen at significantly increased densities in patients with SSc. Alveolar macrophage activation in SSc was also suggested by increased IL-6 concentrations in neat BAL fluid and increases in macrophage production of TNF alpha and EGF in vitro. SSc patients also had increased proportions of neutrophils and eosinophils in BAL fluid. No correlations were found between any cellular subsets or cytokine levels in BAL fluid and lung status at the time of lavage in SSc or pSS patients or the subsequent course of the pulmonary function in SSc patients. CONCLUSION--It is concluded that the phenotypical activation of alveolar helper/inducer (DR+CD4+) and suppressor/cytotoxic (DR+CD8+) T lymphocytes and NK (DR+CD16+) cells is not a prerequisite for the development of lung fibrosis in SSc or bronchial hyper-responsiveness in pSS. Alveolar macrophage activation may contribute to the development of lung fibrosis in SSc.     

Nonhomogeneous Density of CD34 and VCAM-1 Alveolar Capillaries in Major Types of Idiopathic Interstitial Pneumonia

Integrin–immunoglobulin family ligand (CAMs) interactions between lung parenchymal cells (fibroblasts and epithelial cells) and integrin–extracellular matrix component interactions may be involved in the pathogenesis of idiopathic interstitial pneumonia (IIP). Among these, CD34 immunoquantitation allows determination of the degree of vascular proliferation (angiogenesis), whereas VCAM-1 immunoquantitation allows evaluation of the degree of endothelial activity and is strong evidence of inflammation. To validate the importance of vascular proliferation and endothelial cell activity within the alveolar walls and to explore the quantitative relationship between this factor and organizing fibrosis after parenchymal remodeling, we studied surgical lung biopsies in major IIP histologic patterns. We evaluated alveolar vascularity and activity in relation to the various degrees of organizing fibrosis in surgical lung biopsies of diffuse alveolar damage, nonspecific interstitial pneumonia, and usual interstitial pneumonia. Alveolar capillary endothelial cells were intensely immunoreactive with CD34 and VCAM-1. Vascular activity progressively increased in no-organizing fibrotic areas (normal, collapsed, and inflammatory septal areas), whereas vascular density gradually decreased as the degree of organizing fibrosis increased and was lower than that in control lungs in the most extensively fibrotic lesions (mural organizing fibrosis of usual interstitial pneumonia). These results indicate the presence of temporal nonhomogeneic vascular remodeling indiopathic interstitial pneumonia.     

Increased alveolar plasminogen activator in early asbestosis

Alveolar macrophage-derived plasminogen activator (PA) activity is decreased in some chronic interstitial lung diseases such as idiopathic pulmonary fibrosis and sarcoidosis but increased in experimental models of acute alveolitis. Although asbestos fibers can stimulate alveolar macrophages (AM) to release PA in vitro, the effect of chronic asbestos exposure of the lower respiratory tract on lung PA activity remains unknown. The present study was designed to evaluate PA activity of alveolar macrophages and bronchoalveolar lavage (BAL) fluid in asbestos-exposed sheep and asbestos workers. Forty-three sheep were exposed to either 100 mg UICC chrysotile B asbestos in 100 ml phosphate-buffered saline (PBS) or to 100 ml PBS by tracheal infusion every 2 wk for 18 months. At Month 18, chest roentgenograms were analyzed and alveolar macrophage and extracellular fluid PA activity were measured in samples obtained by BAL. Alveolar macrophage PA activity was increased in the asbestos-exposed sheep compared to control sheep (87.2 +/- 17.3 versus 41.1 +/- 7.2 U/10(5) AM-24 h, p less than 0.05) as was the BAL fluid PA activity (674.9 +/- 168.4 versus 81.3 +/- 19.7 U/mg alb-24 h, p less than 0.01). Among the asbestos-exposed sheep, 10 had normal chest roentgenograms (Group SA) and 15 had irregular interstitial opacities (Group SB). Strikingly, whereas Group SA did not differ from the control group in BAL cellularity or PA activity, Group SB had marked increases in alveolar macrophages (p less than 0.005), AM PA activity (p less than 0.02), and BAL PA activity (p less than 0.001) compared to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alveolar macrophages from patients with asbestos exposure release increased levels of leukotriene B4

The alveolar influx and subsequent activation of inflammatory cells such as neutrophils and eosinophils are believed to be important in the pathogenesis of many interstitial lung disorders, including asbestosis. Indices of lower respiratory tract abnormalities detected by bronchoalveolar lavage (BAL) were investigated in 93 asbestos-exposed workers as well as in smoking (n = 12) and nonsmoking (n = 10) control subjects. Patients with clinical asbestosis (n = 12) exhibited increases in both BAL neutrophils and BAL eosinophils, expressed as both percentage of total cells and total numbers, when compared to asbestos-exposed workers without asbestosis (n = 81) and control subjects. Significantly greater numbers of BAL neutrophils were also found in asbestos-exposed workers without asbestosis than in either smoking or nonsmoking control subjects. These abnormalities correlated significantly with in vitro BAL alveolar macrophage production of the potent leukocyte chemotaxin, leukotriene B4 (LTB4). For example, basal, unstimulated LTB4 production was 3.1 +/- 0.8 ng/10(6) alveolar macrophages for patients with asbestosis, 1.05 +/- 0.2 ng/10(6) cells in asbestos workers without asbestosis, 0.9 +/- 0.2 ng/10(6) cells in control nonsmokers, and 0.2 +/- 0.05 ng/10(6) cells in control smokers. Stimulated LTB4 release from BAL alveolar macrophages (A23187 or arachidonate) was even more pronounced in asbestos workers with or without asbestosis, suggesting an in vivo priming effect on alveolar macrophage synthesis of LTB4. Cell-free BAL supernatants from asbestos-exposed patients with or without asbestosis also contained significantly greater amounts of LTB4 than did those from control subjects, indicating enhanced in vivo production of this inflammatory mediator.(ABSTRACT TRUNCATED AT 250 WORDS)     

Neutrophil chemotactic factors in the respiratory tract of patients with chronic airway diseases or idiopathic pulmonary fibrosis.

This study was designed to clarify the contributions of specific neutrophil chemotactic factors (NCF) in neutrophil accumulation in the human respiratory tract associated with various diseases. The activity and characteristics of the NCF in the bronchoalveolar lavage (BAL) fluid and culture media of alveolar macrophages obtained from normal volunteers, control patients, patients with chronic airway diseases (CAD) and patients with idiopathic pulmonary fibrosis (IPF) were examined. The BAL fluid from normal volunteers contained NCF comparable with the chemotactic factors interleukin-8 (IL-8) and leukotriene B4 (LTB4). Analysis of the biochemical characteristics of NCF released from alveolar macrophages suggests that they are derived from alveolar macrophages. The NCF activities in BAL fluids from patients with CAD and IPF were higher than those in BAL fluids from normal volunteers and control patients. Biochemical analysis demonstrated that several kinds of NCF, including those derived from the complement component C5 and alveolar macrophages, were present in the BAL fluid from patients with CAD and respiratory infections. The especially marked increase of C5-derived NCF indicate their importance in neutrophil accumulation in the respiratory tract of patients with CAD. Alveolar macrophages released different types of NCF after different lengths of culture periods (4 h and 24 h). Alveolar macrophages from patients with IPF released larger amounts of NCF than alveolar macrophages from normal volunteers, indicating the importance of alveolar-macrophage-derived NCF as well as C5-derived NCF in neutrophil accumulation in the respiratory tract of patients with IPF. These results suggest that various types of NCF increase in response to different disease states of the respiratory tract and serve to regulate the accumulation of neutrophils.     

Relationship between gallium 67 citrate scanning and transferrin receptor expression in lung diseases.

The uptake of gallium 67 (67Ga) into cells is postulated to be through transferrin receptors (TFR) of 67Ga combined with transferrin. We studied the relationship between gallium 67 citrate scanning (67Ga scan) and immunohistochemical TFR expression in lungs of nine patients with lung cancer and eight patients with diffuse interstitial lung diseases. We found that lung cancer tissues of positive 67Ga scan expressed TFR, but those of a negative scan did not. In all of the five patients with idiopathic pulmonary fibrosis (IPF), TFR were expressed on the membrane of alveolar macrophages that formed clusters. However, TFR were not expressed in lymphocytes, neutrophils, type 2 alveolar epithelial cells, and endothelial cells. In two patients with sarcoidosis and a patient with pneumoconiosis, TFR were expressed positively only on the membrane of foamy alveolar macrophages and epithelioid cells of granuloma. These findings suggest that 67Ga-citrate initially combines with transferrin in the blood and then the complex is incorporated into cells through TFR. Therefore, 67Ga scan could be positive when cells have TFR and one should be able to observe cancer cells, clusters of alveolar macrophages, and epithelioid cells through the imaging of 67Ga scan in lung cancer and diffuse interstitial lung diseases.     

Interstitial lung disease in scleroderma. Analysis by bronchoalveolar lavage

Interstitial pulmonary fibrosis is a common feature of scleroderma (systemic sclerosis) which may result in impairment of pulmonary function and may be a major determinant of morbidity and mortality. Clinicopathologic observations suggest that interstitial and alveolar inflammation may appear prior to fibrosis. Using the bronchoalveolar lavage (BAL) technique, we have characterized the nature of the inflammatory process in the lower respiratory tracts of 19 non-smoking scleroderma patients. Eleven of 19 patients (58%) had increased percentages of neutrophils and/or eosinophils in BAL fluid. Five of 10 patients (50%) had elevations of IgG in BAL fluid. The presence of neutrophils was associated with a decreased lung diffusing capacity for carbon monoxide (P less than 0.05) and with more advanced radiographic features of interstitial fibrosis in patients with disease of more than 1 year's duration. This study suggests that scleroderma lung involvement may be characterized by an inflammatory alveolitis and that the presence of such inflammation may relate to the severity of the pulmonary disease.     

Interstitial lung disease in scleroderma analysis by bronchoalveolar lavage

Interstitial pulmonary fibrosis is a common feature of scleroderma (systemic sclerosis) which may result in impairment of pulmonary function and may be a major determinant of morbidity and mortality. Clinicopathologic observations suggest that interstitial and alveolar inflammation may appear prior to fibrosis. Using the bronchoalveolar lavage (BAL) technique, we have characterized the nature of the inflammatory process in the lower respiratory tracts of 19 nonsmoking scleroderma patients. Eleven of 19 patients (58%) had increased percentages of neutrophils and/or eosinophils in BAL fluid. Five of 10 patients (50%) had elevations of IgG in BAL fluid. The presence of neutrophils was associated with a decreased lung diffusing capacity for carbon monoxide (P < 0.05) and with more advanced radiographic features of interstitial fibrosis in patients with disease of more than 1 year's duration. This study suggests that scleroderma lung involvement may be characterized by an inflammatory alveolitis and that the presence of such inflammation may relate to the severity of the pulmonary disease.     

Phenotype of blood monocytes and alveolar macrophages in interstitial lung disease

The immunologic phenotype of the monocyte-macrophage cell populations in bronchoalveolar lavage (BAL) fluid and monocytes in peripheral blood (PB) were studied in 20 patients with sarcoidosis, 18 with idiopathic pulmonary fibrosis (IPF), seven with extrinsic allergic alveolitis (EAA), and 12 healthy volunteers. There were no significant differences in expression of the immunologic markers CD13(My7), CD14(My4), and Monocyte-2 on blood monocytes between the patient groups and healthy volunteers, but there were marked differences between groups in the expression of the three markers on BAL macrophages. The percentage of Monocyte-2+ macrophages was increased in BAL in subjects with sarcoidosis, EAA, and IPF compared with healthy volunteers, greatest in EAA. This increase is probably due to increased recruitment of blood monocytes into alveoli, since the cells had a monocytic morphology on phase contrast microscopy (in normal subjects the majority of blood monocytes, but few alveolar macrophages, express the Monocyte-2 antigen). Patients with IPF had a significantly lower percentage of CD13(My7)+ macrophages in BAL than the other three groups. Compared with IPF patients and healthy volunteers, patients with EAA had a significantly higher percentage of CD14(My4)+ macrophages, whereas in sarcoidosis patients the numbers were reduced. These observations suggest an increased influx of blood monocytes into the alveoli in interstitial lung disorders. Phenotypic differences were found between the BAL macrophage populations of the various interstitial diseases. These differences in alveolar macrophage phenotype may be due to local factors, depending on the type of inflammation.     

Characterization of the lower respiratory tract inflammation of nonsmoking individuals with interstitial lung disease associated with chronic inhalation of inorganic dusts

The pneumoconioses, interstitial lung disorders resulting from the inhalation of inorganic dusts, are associated with chronic inflammatory processes in the lower respiratory tract. To characterize these inflammatory processes in relation to the pathogenesis of these disorders, we studied 39 nonsmoking individuals with long-term occupational exposures to inorganic dust and functional evidence of interstitial disease (asbestosis, n = 18; coal workers' pneumoconiosis, n = 15; silicosis, n = 6). In all 3 disorders, the inflammation was dominated by alveolar macrophages. Because a common feature of these interstitial lung diseases is concurrent injury and fibrosis of alveolar walls, we assessed whether these alveolar macrophages were spontaneously releasing mediators capable of giving rise to these changes. Alveolar macrophages from the study population were spontaneously releasing increased amounts of superoxide anion and hydrogen peroxide (both p less than 0.01 compared to normals), oxidants capable of injuring lung parenchymal cells. The alveolar macrophages were also spontaneously releasing significantly increased amounts of fibronectin and alveolar macrophage-derived growth factor (both p less than 0.01 compared to normals), mediators that act synergistically to signal fibroblast replication. Taken together, these findings define a major role for the alveolar macrophage in mediating the alveolar wall injury and fibrosis that characterize the common pneumoconioses and suggest that the alveolar macrophage is an important "target" for developing strategies designed to prevent loss of lung function in these individuals.     

Effects of inducible nitric oxide synthase and xanthine oxidase inhibitors on SEB-induced interstitial pneumonia in mice.

The authors have previously reported that intratracheal instillation of staphylococcal enterotoxin-B (SEB) induced interstitial pneumonia (IP) in autoimmune-prone mice. SEB-reactive T-cells were critically involved in the development of IP in this model. Concern has arisen about the hazards of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the process of lung injury and fibrosis. Therefore, the involvement of nitric oxide (NO) and superoxide anion (O2-) in the pathogenesis of IP in this autoimmune-prone model has been investigated. Nitrite/nitrate levels were increased in bronchoalveolar lavage (BAL) fluid and serum from SEB-injected mice. The signal of the NO-(N-(dithiocarboxy) sarcosine)2-Fe2+ complex was detected in the SEB-injected lung and whole blood by electron paramagnetic resonance (EPR) spectroscopy. NO production was significantly decreased by aminoguanidine (AG) treatment. Xanthine oxidase (XO) activity in the lung, BAL fluid, and plasma was increased with instillation of SEB, and 4-amino-6-hydroxypyrazolo(3,4-d)-pyrimidine (AHPP) significantly inhibited XO activity. Moreover, both AG and AHPP significantly decreased production of pro-inflammatory cytokines, numbers of infiltrated cells in BAL fluid, and the area of thickened alveolar septa in the SEB-injected lung. In conclusion, the overproduction of nitric oxide and super oxide anion were implicated in the pathogenesis of interstitial pneumonia, and inducible nitric oxide synthase and xanthine oxidase inhibitors had protective effects against interstitial pneumonia in this model.