Elevated interleukin-18 levels in bronchoalveolar lavage fluid of patients with eosinophilic pneumonia

BACKGROUND: Interleukin (IL)-18 can induce Th2 cytokine production particularly in collaboration with IL-2. Accumulation of Th2 cells and increased levels of Th2 cytokines are found in bronchoalveolar lavage fluid (BALF) from patients with eosinophilic pneumonia (EP). To evaluate the role of IL-18 in the pathogenesis of EP, we measured the concentration of IL-2, IL-12, IL-18, and Th2 cytokines in BALF from patients with EP. METHODS: The concentrations of interferon (IFN)-gamma, IL-2, IL-5, IL-10, IL-12, IL-13, and IL-18 in BALF were measured in patients with idiopathic acute eosinophilic pneumonia (AEP), with idiopathic chronic eosinophilic pneumonia (CEP), with sarcoidosis and healthy volunteers (HV). RESULTS: The BALF concentrations of Th2 cytokines, IL-5, IL-10, and IL-13, were higher in patients with EP than in sarcoidosis and control. The IL-2 level in BALF was higher in EP than in sarcoidosis and control. The IL-18 and IL-12 (p40 + p70) levels were higher in patients with EP than sarcoidosis, while the level of IL-12 (p70) was below the detection limit in patients with EP. There was a significant correlation between IL-2 level and both IL-5 and IL-13 in BALF of patients with EP. CONCLUSIONS: Our findings suggest that IL-18 may contribute to Th2 cytokine-dominant responses in patients with EP in collaboration with IL-2.     

Upregulation of Th1 cytokine profile (IL-12, IL-18) in bronchoalveolar lavage fluid in patients with pulmonary sarcoidosis.

Sarcoidosis, a systemic granulomatous disease of unknown etiology, is characterized by a predominantly Th1 cytokine milieu, which is involved in its immunopathogenesis. The role of novel immunologic markers reflecting T cell activity of the sarcoid immunologic response needs to be determined. The present study aims to evaluate the role of the Th1 cytokine pattern by estimating the local and systemic levels of interleukin-12 (IL-12) and IL-18 in bronchoalveolar lavage fluid (BALF), induced sputum, and serum of patients with pulmonary sarcoidosis. We studied prospectively 20 patients (12 women, 8 men) of median age 46 years (range 25-65) with sarcoidosis and 10 normal subjects (5 women, 5 men) of median age 39 years (range 26-60). IL-12 and IL-18 levels were measured using ELISA kits. The IL-12 BALF levels were significantly higher in sarcoidosis patients than in healthy subjects (5.64 +/- 0.21 pg/mL vs. 5.16 +/- 0.15 pg/mL, p < 0.001). In addition, IL-18 levels were significantly increased in BALF samples (47.69 +/- 6.29 pg/mL vs. 16.73 +/- 3.00 pg/mL, p < 0.001). A statistically significant decrease in IL-12 serum levels was detected in the sarcoid population compared with controls (5.77 +/- 0.50 pg/mL vs. 7.87 +/- 2.00 pg/mL, p < 0.001). No significant differences were detected in IL-12 and IL-18 levels between patients and controls in induced sputum samples. Our data suggest a potential role of IL-12 and IL-18 in the local immunologic response in pulmonary sarcoidosis. Further large-scale studies are needed to define the precise role of IL-12 and IL-18 in the immunopathogenesis of this disorder.     

Increased IL-6 and IL-8 in bronchoalveolar lavage fluids (BALF) from patients with sarcoidosis: correlation with the clinical parameters

A variety of cytokines have been implicated in the pathogenesis of pulmonary sarcoidosis, but the exact roles of IL-6 and IL-8 are not yet clear. We studied these cytokine levels in BALF from patients with pulmonary sarcoidosis, idiopathic pulmonary fibrosis (IPF), systemic screlosis (SSc) with interstitial lung disease and control subjects. IL-6 and IL-8 levels were significantly elevated in sarcoidosis, IPF and SSc with interstitial lung disease compared with control subjects. Subjects with sarcoidosis had significantly increased levels of both cytokines compared with controls when the cytokine values were corrected by the total albumin content and the two cytokine levels correlated with each other (r=0.876). BALF IL-6 levels correlated with percent lymphocytes and percent CD3⁺ cells. Moreover, when sarcoidosis patients were divided into three groups, those who needed steroid therapy or had progressive disease showed increased cytokine levels in BALF over stable or improved patients. These observations suggest that locally derived IL-6 and IL-8 were increased in sarcoidosis and correlated with activity of this granulomatous lung disease.     

Bronchoalveolar Lavage Fluid Cellular Characteristics, Functional Parameters and Cytokine and Chemokine Levels in Interstitial Lung Diseases

Idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis (HP) and sarcoidosis belong to interstitial lung diseases (ILD) where an imbalance of regulatory, profibrotic and antifibrotic cytokines is hypothesized. The relationship of bronchoalveolar lavage (BAL) fluid (BALF) cytokines, BALF cell profile and ILD course is supposed. The aim of our study was to correlate BALF cytokine and chemokine levels with BALF cellular characteristics and lung function parameters in different ILD. Twenty-two sarcoidosis, seven IPF and 11 HP patients underwent lung function tests and BAL. The BALF differential cell counts and superficial cell markers were characterized, and MCP-1, MIP-1α, MIP-1β, RANTES, epithelial neutrophil-activating protein (ENA)-78, FGF, G-CSF, GM-CSF, IFN-γ, interleukin (IL)-1α, IL-1RA, IL-1β, -2β, -4β, -5β, -6β, -8β, -10β, -17β, tumour necrosis factor (TNF)-α, thromobopoietin (Tpo) and vascular endothelial growth factor (VEGF) values measured. The BALF VEGF values were highest in sarcoidosis ( P  = 0.0526). IL-1RA values were higher in IPF and HP compared with sarcoidosis ( P  = 0.0334). IL-8/ENA-78 ratio positively correlated with BALF neutrophil counts in IPF ( r  = 0.89, P  = 0.04). Vital capacity and TL_CO values positively correlated with VEGF and negatively with IL-8 BALF levels in all ILDs but the correlations were most significant in sarcoidosis group. We suppose that VEGF plays a role in ILDs' early phases and has rather angiogenic than profibrotic effect. On the contrary, IL-8 is probably upregulated in advanced ILDs with prominent fibrosis and marked lung functions decline. We state that BALF VEGF, IL-8 and ENA-78 levels and IL-8/ENA-78 ratio could become useful markers of ILDs' phase, activity and prognosis. They might also be helpful in treatment modality choice.     

Cytokines in symptomatic asthma airways.

To determine whether cytokines are generated in vivo in subjects with asthma, we have measured cytokine levels (tumor necrosis factor [TNF], granulocyte-macrophage-colony-stimulating factor [GM-CSF], interleukin [IL]-1 alpha, IL-1 beta, IL-2, IL-4, and IL-6) in the airways of subjects with symptomatic (N = 24) and asymptomatic (N = 9) asthma with immunoassays (GM-CSF, IL-1 alpha, IL-1 beta, IL-2, and IL-4) or bioassays (TNF and IL-6) and the polymerase chain reaction (IL-1 beta and TNF). Significant levels of TNF (578 +/- 917 pg/ml versus 24 +/- 29 pg/ml) (p = 0.01), GM-CSF (24 +/- 41 pg/ml versus less than 8 pg/ml) (p = 0.02), and IL-6 (225 +/- 327 pg/ml versus 7 +/- 12 pg/ml) (p = 0.01), but not IL-1 alpha or IL-4, were detected in the bronchoalveolar lavage fluid (BALF) of patients with symptomatic compared with BALF of patients with asymptomatic asthma. Levels of IL-1 beta (266 +/- 270 pg/ml versus less than 20 pg/ml) (p = 0.001) and IL-2 (1.4 +/- 2.8 ng/ml versus less than 0.3 ng/ml) (p = 0.05) in BALF in patients with symptomatic compared with that in BALF levels in patients with asymptomatic asthma suggested activation of alveolar macrophages and T cells. Thus, in episodes of asthma, several cytokines, including TNF, GM-CSF, IL-1 beta, IL-2, and IL-6 are detectable in BALF.     

Spontaneous production of various cytokines except IL-4 from CD4+ T cells in the affected organs of sarcoidosis patients.

We investigated surface antigens and spontaneous cytokine production of T cells from bronchoalveolar lavage fluid (BALF) and aqueous humor (AH) from pulmonary sarcoidosis patients for a better understanding of the role of T cells in granuloma formation. The levels of CD3, CD11b, and CD28 antigen expression on freshly isolated T cells in the BALF of patients were significantly lower than those in peripheral blood lymphocytes (PBL) of either sarcoidosis patients or healthy donors (HD). In contrast, the levels of CD80 (B7/B7-1) and CD86 (B70/B7-2) antigen expression were significantly higher on these T cells and alveolar macrophages in the BALF of patients. Fifty-three T cell clones (TCC) established from the BALF and AH of the three sarcoidosis patients displayed primarily either CD4+ CD11b+ CD28+ or CD4+ CD11b- CD28- phenotypes. Most (61-90%) of these TCC spontaneously produced greater amounts of IL-1 alpha, IL-10, tumour necrosis factor (TNF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) than did TCC from the PBL from sarcoidosis patients or HD (P < 0.05). Interferon-gamma (IFN-gamma), IL-6, and IL-2, but not IL-4, were also produced by 40-48% of these TCC. These results suggest that CD4+ T cells of the affected organs of sarcoidosis patients are activated and involved in the immunopathogenesis of sarcoidosis through production of various cytokines.     

Elevated matrilysin levels in bronchoalveolar lavage fluid do not distinguish idiopathic pulmonary fibrosis from other interstitial lung diseases

Microarray studies have shown that matrilysin or matrix metalloproteinase (MMP)-7 is highly upregulated in the lungs of patients with idiopathic pulmonary fibrosis (IPF), but MMP-7 protein expression has not been systematically compared between IPF and other interstitial lung diseases. MMP-7 levels in bronchoalveolar lavage fluid (BALF) were compared to corresponding samples from nonspecific interstitial pneumonia (NSIP), sarcoidosis, and healthy controls. MMP-7 levels in the BALF were determined by ELISA and localization of MMP-7 in the lung tissue by immunohistochemistry. MMP-7 was similarly elevated in the BALF of all these disorders compared to healthy controls (p=0.007). Even control subjects with prolonged cough displayed a tendency towards elevated MMP-7 expression. There was a negative correlation between BALF MMP-7 levels and forced expiratory vital capacity (r=-0.348, p=0.02, n=42). In IPF lung, MMP-7 immunoreactivity appeared predominantly in the fibrotic parenchyma and arterial wall. In sarcoidosis and NSIP, prominent MMP-7 immunoreactivity was found in areas of inflammation. These results demonstrate that elevated BALF MMP-7 is not restricted to IPF alone but is also observed in other interstitial lung diseases and cannot be used as a differential diagnostic marker for IPF.     

Histamine levels in bronchoalveolar lavage from patients with asthma, sarcoidosis, and idiopathic pulmonary fibrosis

Bronchoalveolar lavage (BAL) has been used extensively as a research tool to elucidate immunologic events occurring in the lower respiratory tract of patients with numerous diseases and, most recently, to study patients with asthma. We assessed mast-basophiloid cell numbers and histamine levels with a sensitive histamine assay, lower limit of sensitivity, 25 pg/ml, in BAL fluid from normal individuals (n = 9) and compared these results to those obtained from patients with sarcoidosis (n = 31), idiopathic pulmonary fibrosis (IPF) (n = 8), and mild asthma (n = 7). Patients with sarcoidosis demonstrated a significant increase in total BAL mast-basophiloid cells, 9.6 +/- 4.1 X 10(4), compared to total cells in normal individuals, 0.0, p = 0.03, whereas only patients with IPF had significant elevations in BAL histamine levels, 1315 +/- 737 pg/ml, versus levels in normal individuals, 161 +/- 54 pg/ml, p = 0.002. A good correlation existed between histamine levels on an aliquot of lysed BAL cells and BAL histamine levels, R = 0.655 and p = 0.02, but not with either the total number or percent mast-basophiloid cells in BAL assessed on Wright's stained cytocentrifuge preparations. Subjects with asthma had both normal numbers of BAL mast-basophiloid cells and histamine levels. These data suggest that BAL histamine levels are easily quantified, the reason(s) for elevations in BAL histamine levels in IPF need further investigation, BAL histamine levels in subjects with asthma are not elevated in those with mild and stable disease, and lumenal mast-basophiloid cells are one major source of BAL histamine.     

MRP14 is elevated in the bronchoalveolar lavage fluid of fibrosing interstitial lung diseases

Pulmonary fibrosis is defined by an overgrowth of fibroblasts and extracellular matrix deposition, and results in respiratory dysfunction that is often fatal. It is the end stage in many chronic inflammatory interstitial lung diseases (ILD) such as sarcoidosis and idiopathic pulmonary fibrosis (IPF). The myeloid‐related proteins (MRPs) belong to the S100 family of calcium‐binding proteins and are highly expressed by neutrophils, macrophages and epithelial cells during chronic inflammation. MRP14 stimulates fibroblast proliferation in vitro and is expressed in granulomas from sarcoidosis patients. We hypothesized that MRP14 may be a biomarker for fibrotic interstitial lung diseases. The objective of this study was to investigate whether levels of MRP14 in the bronchoalveolar lavage fluid (BALF) of patients with sarcoidosis and IPF correlate with clinical parameters. We used an enzyme‐linked immunosorbent assay (ELISA) to measure MRP14 in BALF of 74 sarcoidosis patients, 54 IPF patients and 19 controls. Mean BALF levels of MRP14 were elevated significantly in IPF (P < 0·001) and sarcoidosis (P < 0·05) patients compared to controls. MRP14 levels were associated linearly with sarcoidosis disease severity based on chest radiographic stage. Moreover, BALF MRP14 levels were correlated inversely with diffusion capacity and forced vital capacity in sarcoidosis patients. In IPF patients, a correlation with BALF neutrophil percentage was found. In conclusion, BALF MRP14 levels are elevated in IPF and sarcoidosis and are associated with disease severity in sarcoidosis. The results support the need for further studies into the role of MRP14 in the pathogenesis of lung fibrosis.     

IL-18 might reflect disease activity in mild and moderate asthma exacerbation

BACKGROUND: IL-18, identified as an IFN-gamma-inducing factor, is a proinflammatory cytokine that plays an important role in TH1 cell activation. Recently, it was reported that histamine induced IL-18 and that IL-18 might act as a coinducer of TH1 and TH2 cytokines. OBJECTIVE: The aim was to evaluate the contribution of IL-18 to asthma exacerbation. METHODS: Serum IL-18, soluble IL-2 receptor, eosinophil cationic protein, and plasma IFN-gamma levels, as well as peak expiratory flow were measured in patients with stable asthma (n = 28), acute mild or moderate asthma (n = 23), or pulmonary sarcoidosis (n = 35) and in healthy subjects (n = 26). We compared the serum IL-18 levels between patients with acute asthma and those in remission and examined the time course in acute exacerbation after asthma therapy. RESULTS: Significantly higher serum IL-18 levels were found in patients with acute asthma (215 +/- 33 pg/mL, mean +/- SE; P = .02) and pulmonary sarcoidosis (239 +/- 27 pg/mL, P = .008) than in control subjects (127 +/- 11 pg/mL), but the plasma IFN-gamma level was significantly elevated in only pulmonary sarcoidosis (P < .001). In pulmonary sarcoidosis the IL-18 values significantly correlated with the IFN-gamma levels (r = 0.61, P < .001), but in acute asthma they did not. The IL-18 levels during acute asthma exacerbation were significantly higher (P = .01) than on remission days. In acute asthma, circulating IL-18 levels significantly correlated with serum soluble IL-2 receptor levels (r = 0.77, P < .0001) but not with serum eosinophil cationic protein levels. The IL-18 level had a tendency to inversely correlate with peak expiratory flow. The elevated IL-18 levels in acute asthma quickly decreased on day 3 (P = .02) and day 7 (P = .002) after therapy. CONCLUSION: It was suggested that IL-18 may play a potential role to activate immunologic responses and may reflect disease activity in mild and moderate asthma exacerbation.     

Increased circulating interleukin-12 (IL-12) p40 in pulmonary sarcoidosis

In sarcoidosis, a T helper 1 (Th1) response is an essential event and the up-regulation of interleukin-12 (IL-12) has been detected in affected disease sites. In order to investigate the clinical usefulness of circulating IL-12, we measured the serum concentrations of IL-12 by ELISA and performed immunohistochemistry using specific MoAbs for IL-12 in the lungs and scalene lymph nodes of patients with sarcoidosis. The serum concentration of IL-12 p40 was detectable in all 45 patients with pulmonary sarcoidosis and 18 normal controls, whereas that of IL-12 p70 was undetectable. The serum concentrations of IL-12 p40 in pulmonary sarcoidosis were significantly higher than those of the normal controls, especially in cases with abnormal intrathoracic findings detected by chest roentogenogram. The serum concentrations of interferon-gamma (IFN-gamma) also increased compared with those of normal controls and there was a significant positive correlation between the serum concentrations of IL-12 p40 and IFN-gamma. Furthermore, serum angiotensin-converting enzyme (ACE) and lysozyme, which are known to be useful markers for disease activity in sarcoidosis, correlated well with the serum concentrations of IL-12 p40. The positive 67Ga scan group (for lung field) had significantly elevated serum IL-12 p40 levels compared with those of the negative group. No bioactivity of IL-12 p70 was detected in three sarcoid cases sera by using the IL-12 responsive cell line. Finally, the immunohistochemical approach revealed that IL-12 p40 was expressed in the epithelioid cells and macrophages of sarcoid lungs and lymph nodes. We concluded that the production of IL-12 p40 was far greater in the sera and we have demonstrated this to be a useful clinical marker for disease activity and the Th1 response in pulmonary sarcoidosis.     

Expression of mucosa-related integrin alphaEbeta7 on alveolar T cells in interstitial lung diseases.

The expression of alphaEbeta7 integrin has been related to the selective retention of lymphocytes in mucosal tissues of gut, urogenital tract and lung. To identify potential disease-associated alphaEbeta7 expression patterns on cells accounting for lymphocytic alveolitis in interstitial lung disease (ILD), alphaE expression on CD4+ and CD8+ T cell subsets was evaluated by dual-colour flow cytometry in peripheral blood and bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF; n = 18), hypersensitivity pneumonitis (HP; n = 20) and sarcoidosis (n = 44) in comparison with healthy controls (n = 15). In both healthy individuals and all patient groups the proportion of alphaE-bearing T cells in peripheral blood was < 2%, whereas the vast majority of alveolar CD8+ T cells consistently co-expressed alphaE. Absolute alveolar CD8+alphaE+ cell numbers/ml were up to 30-fold increased in HP patients. Proportions of alphaE-bearing CD4+ cells in BALF were significantly elevated in IPF (74.0 +/- 2.7%) and HP (70.0 +/- 2.4%) compared with normals (30.0 +/- 1.8%) (mean +/- s.e.m.; P < 0.01). In sarcoidosis, the alphaE expression on BALF CD4+ cells displayed subgroup dependency: proportions significantly lower than normal were noted in chest radiographic stage I (14.3 +/- 1.5%), but increased proportions in stages II (50.0 +/- 3.8%) and III (64.0 +/- 4.8%). Correlations between common markers of T cell activation or BALF transforming growth factor-beta (TGF-beta ) bioactivity and alphaE expression were not noted. We conclude that the vast majority of alveolar CD8+ T cells consistently express alphaEbeta7 and that distinct patterns of alphaEbeta7 expression on alveolar CD4+ lymphocytes in sarcoidosis are related to the diverse manifestations of the sarcoid inflammatory process in the lung.     

Transient elevation of interleukin-16 levels at the initial stage of meningitis in children

IL-16 is an immunomodulatory cytokine that is characterized by chemotactic activity and stimulation of proinflammatory cytokine expression in monocytic cells. We studied IL-16 using ELISA in children with meningitis. When meningeal symptoms existed, IL-16 levels were high in the cerebrospinal fluid (CSF) of both bacterial (939 +/- 877 ng/l, n = 20) and aseptic (341 +/- 371 ng/l, n = 23) meningitis. The values in the CSF were significantly higher than those in non-meningitis controls (29 +/- 8 ng/l, n = 22, P < 0.0001). After meningeal symptoms disappeared, IL-16 levels in bacterial (191 +/- 149 ng/l, n = 10, P = 0.0042) and aseptic (159 +/- 188 ng/l, n = 13, P = 0.0118) meningitis were lower than those during the symptomatic stage. IL-16 levels were the highest before day 5 of the illness and then gradually fell. Significant correlations were found between IL-16 levels and both G-CSF levels (r = 0.783, n = 11, p = 0.0029) and IL-6 levels (r = 0.818, n = 12, P = 0.0005) in the CSF of bacterial and aseptic meningitis. IL-16 levels in all CSF samples from non-meningitis controls were lower than those in serum. In contrast, IL-16 levels in the CSF in six of 16 samples from bacterial meningitis and two of 18 samples from aseptic meningitis were higher than those in serum. Serum levels of IL-16 did not fluctuate throughout the course of meningitis. These data indicate that IL-16 levels rise transiently in CSF at the initial stage of meningitis. We speculate that IL-16 may promote inflammatory responses during meningitis in concert with other proinflammatory cytokines.     

Th1 cytokine pattern in sarcoidosis is expressed by bronchoalveolar CD4+ and CD8+ T cells

The pathogenesis of pulmonary sarcoidosis has been related to an increased production of Th1-like cytokines. However, cytokine expression in sarcoidosis has not been systematically studied at a single-cell level. We therefore investigated the expression of IL-2, IL-4, IL-13, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) intracellularly in bronchoalveolar lavage (BAL) and peripheral blood CD3+ T lymphocytes from patients with pulmonary sarcoidosis (radiologic stage II-III, n = 8) and normal controls (n = 9) by flow cytometry. In contrast to IL-4 and IL-13, the percentage of T lymphocytes expressing intracellular IL-2 (49.3 +/- 21.3% versus 14.5 +/- 15.6%), IFN-gamma (75.5 +/- 14.9% versus 32.6 +/- 18.7%) and TNF-alpha (68.3 +/- 18.7% versus 36.8 +/- 20.8%) was significantly higher in patients with sarcoidosis than in normal controls (each P < 0.005). In contrast to BAL lymphocytes, expression of these cytokines in peripheral blood lymphocytes did not differ between patients with sarcoidosis and normal controls. Close correlations were observed between the percentages of BAL lymphocytes expressing intracellular IL-2, IFN-gamma and TNF-alpha, but not for IL-4 or IL-13. Analysis of the expression of these cytokines in T lymphocyte subsets revealed IL-2, IFN-gamma, and TNF-alpha in CD4+ as well as CD8+ T lymphocytes, suggesting a contribution of TC1 cells to the production of proinflammatory cytokines in sarcoidosis. We conclude that a Th1-like cytokine pattern can be observed in CD4+ as well as in CD8+ BAL T lymphocytes in patients with pulmonary sarcoidosis.     

Interleukin-12B-3'UTR polymorphism in association with IL-12p40 and IL-12p70 serum levels and silicosis severity

Susceptibility to silicosis and to disease severity is in part genetically determined. In this study, the role of IL-12B-3'UTR polymorphism in susceptibility and severity of silicosis and its influence on IL-12p40 and IL-12p70 serum level were investigated. The quantity of IL-12p40 and IL-12p70 was detected by enzyme-linked immunosorbent assay and the genotype of IL-12B was determined using the polymerase chain reaction-restriction fragment-length polymorphism method. We observed elevated IL-12p40 in contrast to IL-12p70 serum levels in a group of 62 silicosis patients compared with both control groups. In severe silicosis patients, we detected the highest IL-12p40 serum levels (129.1 +/- 67.7 pg mL(-1)); lower in patients with the moderate (94 +/- 41.6 pg mL(-1)), whereas in mild silicosis, the IL-12p40 levels (67 +/- 23.5 pg mL(-1)) was similar to these in healthy donors. According to IL-12B polymorphism, increased serum levels were observed in subjects with AA genotype (103.2 +/- 46.9 pg mL(-1)) compared to silicosis patients with AC genotype (82.7 +/- 38.3 pg mL(-1)). No significant differences of genotype and allele frequencies of the 3'UTR polymorphism were observed between silicosis patients and healthy controls. However, the heterozygous genotype was found approximately five times more frequently in patients with mild and moderate (48% and 52%) silicosis compared to patients with severe silicosis (11%), and that IL-12B polymorphism may contribute to silicosis severity rather than to susceptibility. Our data demonstrated that elevated serum IL-12p40, independently of IL-12p70 levels, is associated with severity of silicosis, and suggested that IL-12p40 profibrotic activity may contribute to silicosis severity.     

Evaluation of soluble IL-6 receptor concentration in serum and epithelial lining fluid from patients with interstitial lung diseases.

We measured soluble IL-6 receptor (sIL-6R) levels in serum and bronchoalveolar lavage fluids (BALF) from patients with interstitial pneumonia of unknown etiology (IP) (n = 17), sarcoidosis (n = 8) and normal control subjects (n = 10), to investigate its role in pulmonary diseases. Soluble IL-6R was determined by an ELISA. The volume of epithelial lining fluid (ELF) in BALF was estimated using an urea method. We found that levels of sIL-6R in serum, BALF, and ELF from patients with IP or sarcoidosis were significantly higher than those from normal subjects. Furthermore, levels of sIL-6R in BALF or ELF were significantly correlated with those of albumin, indicating that sIL-6R, together with albumin, may enter ELF as a result of the increased permeability caused by pulmonary inflammation. Thus most of the sIL-6R in ELF would be from serum, and relatively small amounts of it might be produced locally. However, sIL-6R levels in ELF, but neither serum nor BALF, were significantly correlated with levels of C-reactive protein in patients with IP. These results suggest that both systemic and local production of sIL-6R are increased, and raised sIL-6R is involved in the modulation of systemic and local inflammatory responses in patients with IP and sarcoidosis.     

Genetic variability in the IL1RN gene and the balance between interleukin (IL)-1 receptor agonist and IL-1β in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rapidly progressive interstitial lung disease of unknown aetiology. Interleukin (IL)-1β plays an important role in inflammation and has been associated with fibrotic remodelling. We investigated the balance between IL-1β and IL-1 receptor antagonist (IL-1Ra) in bronchoalveolar lavage fluid (BALF) and serum as well as the influence of genetic variability in the IL1B and IL1RN gene on disease susceptibility and cytokine levels. In 77 IPF patients and 349 healthy controls, single nucleotide polymorphisms (SNPs) in the IL1RN and IL1B genes were determined. Serum and BALF IL-1Ra and IL-1β levels were measured using a multiplex suspension bead array system and were correlated with genotypes. Both in serum and BALF a significantly decreased IL-1Ra/IL-1β ratio was found in IPF patients compared to healthy controls. In the IL1RN gene, one SNP was associated with both the susceptibility to IPF and reduced IL-1Ra/IL-1β ratios in BALF. Our results show that genetic variability in the IL1RN gene may play a role in the pathogenesis of IPF and that this role may be more important than thought until recently. The imbalance between IL-1Ra and IL-1β might contribute to a proinflammatory and pro-fibrotic environment in their lungs.     

A TaqI polymorphism in the 3'UTR of the IL-12 p40 gene correlates with increased IL-12 secretion

Interleukin-12 (IL-12) is a key cytokine for the induction of Th1 immune responses. We evaluated whether a TaqI polymorphism in the 3'UTR of the IL-12 p40 gene affects secretion of IL-12 in vitro, and whether this polymorphism is associated with susceptibility to Crohn's disease (CD). IL-12 p40 and p70 secretion by monocytes in relation to genotype was determined in 63 healthy donors. Genotype and allele frequencies of the TaqI polymorphism in 150 CD patients were compared with 145 ethnically matched healthy controls (HC). No significant association was found between genotype and IL-12 p40 secretion after stimulation of monocytes with SAC+IFNgamma. In contrast, increasing IL-12 p70 secretion was found across the categories of non-carriers, heterozygotes and homozygotes for the variant allele (median values+/-SEM: 147+/-27, 282+/-51 and 482+/-34 pg/ml, respectively; P<0.005). The allele and genotype frequencies of this polymorphism in patients with CD did not differ statistically significantly from HC. The presence of a TaqI polymorphism in the IL12 p40 3'UTR correlates with increased in vitro IL-12 p70, but not p40 secretion. While this polymorphism does not appear to be correlated with susceptibility to CD in the limited population of patients tested here, it could influence the occurrence of the disease in certain subsets of patients.