Detection of endogenous cytokines in sera or in lymph nodes obtained from patients with sarcoidosis

Multi-omic signatures of sarcoidosis and progression in bronchoalveolar lavage cells

BACKGROUND

Sarcoidosis is a heterogeneous granulomatous disease with no accurate biomarkers of disease progression. Therefore, we profiled and integrated the DNA methylome, mRNAs, and microRNAs to identify molecular changes associated with sarcoidosis and disease progression that might illuminate underlying mechanisms of disease and potential biomarkers.

METHODS

Bronchoalveolar lavage cells from 64 sarcoidosis subjects and 16 healthy controls were used. DNA methylation was profiled on Illumina HumanMethylationEPIC arrays, mRNA by RNA-sequencing, and miRNAs by small RNA-sequencing. Linear models were fit to test for effect of sarcoidosis diagnosis and progression phenotype, adjusting for age, sex, smoking, and principal components of the data. We built a supervised multi-omics model using a subset of features from each dataset.

RESULTS

We identified 1,459 CpGs, 64 mRNAs, and five miRNAs associated with sarcoidosis versus controls and four mRNAs associated with disease progression. Our integrated model emphasized the prominence of the PI3K/AKT1 pathway, which is important in T cell and mTOR function. Novel immune related genes and miRNAs including LYST, RGS14, SLFN12L, and hsa-miR-199b-5p, distinguished sarcoidosis from controls. Our integrated model also demonstrated differential expression/methylation of IL20RB, ABCC11, SFSWAP, AGBL4, miR-146a-3p, and miR-378b between non-progressive and progressive sarcoidosis.

CONCLUSIONS

Leveraging the DNA methylome, transcriptome, and miRNA-sequencing in sarcoidosis BAL cells, we detected widespread molecular changes associated with disease, many which are involved in immune response. These molecules may serve as diagnostic/prognostic biomarkers and/or drug targets, although future testing is required for confirmation.

Multi-Omic Signatures of Sarcoidosis and Progression in Bronchoalveolar Lavage Cells

Introduction

Sarcoidosis is a heterogeneous, granulomatous disease that can prove difficult to diagnose, with no accurate biomarkers of disease progression. Therefore, we profiled and integrated the DNA methylome, mRNAs, and microRNAs to identify molecular changes associated with sarcoidosis and disease progression that might illuminate underlying mechanisms of disease and potential genomic biomarkers.

Methods

Bronchoalveolar lavage cells from 64 sarcoidosis subjects and 16 healthy controls were used. DNA methylation was profiled on Illumina HumanMethylationEPIC arrays, mRNA by RNA-sequencing, and miRNAs by small RNA-sequencing. Linear models were fit to test for effect of diagnosis and phenotype, adjusting for age, sex, and smoking. We built a supervised multi-omics model using a subset of features from each dataset.

Results

We identified 46,812 CpGs, 1,842 mRNAs, and 5 miRNAs associated with sarcoidosis versus controls and 1 mRNA, SEPP1 - a protein that supplies selenium to cells, associated with disease progression. Our integrated model emphasized the prominence of the PI3K/AKT1 pathway in sarcoidosis, which is important in T cell and mTOR function. Novel immune related genes and miRNAs including LYST, RGS14, SLFN12L, and hsa-miR-199b-5p, distinguished sarcoidosis from controls. Our integrated model also demonstrated differential expression/methylation of IL20RB, ABCC11, SFSWAP, AGBL4, miR-146a-3p, and miR-378b between non-progressive and progressive sarcoidosis.

Conclusions

Leveraging the DNA methylome, transcriptome, and miRNA-sequencing in sarcoidosis BAL cells, we detected widespread molecular changes associated with disease, many which are involved in immune response. These molecules may serve as diagnostic/prognostic biomarkers and/or drug targets, although future testing will be required for confirmation.

Epigenetics and sarcoidosis

Epigenetic modifications are emerging as important regulatory mechanisms of gene expression in lung disease, given that they are influenced by environmental exposures and genetic variants, and that they regulate immune and fibrotic processes. In this review, we introduce these concepts with a focus on the study of DNA methylation and histone modifications and discuss how they have been applied to lung disease, and how they can be applied to sarcoidosis. This information has implications for other exposure and immunologically mediated lung diseases, such as chronic beryllium disease, hypersensitivity pneumonitis, and asbestosis.

Studies in a Murine Granuloma Model of Instilled Carbon Nanotubes: Relevance to Sarcoidosis

Poorly soluble environmental antigens, including carbon pollutants, are thought to play a role in the incidence of human sarcoidosis, a chronic inflammatory granulomatous disease of unknown causation. Currently, engineered carbon products such as multiwall carbon nanotubes (MWCNT) are manufactured commercially and have been shown to elicit acute and chronic inflammatory responses in experimental animals, including the production of granulomas or fibrosis. Several years ago, we hypothesized that constructing an experimental model of chronic granulomatosis resembling that associated with sarcoidosis might be achieved by oropharyngeal instillation of MWCNT into mice. This review summarizes the results of our efforts to define mechanisms of granuloma formation and identify potential therapeutic targets for sarcoidosis. Evidence is presented linking findings from the murine MWCNT granuloma model to sarcoidosis pathophysiology. As our goal was to determine what pulmonary inflammatory pathways might be involved, we utilized mice of knock-out (KO) backgrounds which corresponded to deficiencies noted in sarcoidosis patients. A primary example of this approach was to study mice with a myeloid-specific knock-out of the lipid-regulated transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ) which is strikingly depressed in sarcoidosis. Among the major findings associated with PPARγ KO mice compared to wild-type were: (1) exacerbation of granulomatous and fibrotic histopathology in response to MWCNT; (2) elevation of inflammatory mediators; and (3) pulmonary retention of a potentially antigenic ESAT-6 peptide co-instilled with MWCNT. In line with these data, we also observed that activation of PPARγ in wild-type mice by the PPARγ-specific ligand, rosiglitazone, significantly reduced both pulmonary granuloma and inflammatory mediator production. Similarly, recognition of a deficiency of ATP-binding cassette (ABC) lipid transporter ABCG1 in sarcoidosis led us to study MWCNT instillation in myeloid-specific ABCG1 KO mice. As anticipated, ABCG1 deficiency was associated with larger granulomas and increased levels of inflammatory mediators. Finally, a transcriptional survey of alveolar macrophages from MWCNT-instilled wild-type mice and human sarcoidosis patients revealed several common themes. One of the most prominent mediators identified in both human and mouse transcriptomic analyses was MMP12. Studies with MMP12 KO mice revealed similar acute reactions to those in wild-type but at chronic time points where wild-type maintained granulomatous disease, resolution occurred with MMP12 KO mice suggesting MMP12 is necessary for granuloma progression. In conclusion, these studies suggest that the MWCNT granuloma model has relevance to human sarcoidosis study, particularly with respect to immune-specific pathways.

Matrix Metalloproteinase-12 Is Required for Granuloma Progression

Background

Sarcoidosis is a chronic inflammatory disease of unknown cause characterized by granuloma formation. Mechanisms for chronic persistence of granulomas are unknown. Matrix Metalloproteinase-12 (MMP12) degrades extracellular matrix elastin and enables infiltration of immune cells responsible for inflammation and granuloma formation. Previous studies report increased MMP12 in sarcoidosis patients and association between MMP12 expression and disease severity. We also observed elevated MMP12 in our multiwall carbon nanotube (MWCNT) murine model of granulomatous inflammation. Here we hypothesized that MMP12 is important to acute and late phases of granuloma pathogenesis. To test this hypothesis, we analyzed granulomatous and inflammatory responses of Mmp12 knock-out (KO) mice at 10 (acute) and 60 days (late) after MWCNT instillation.

Methods

C57BL/6 (wildtype) and Mmp12 KO mice underwent oropharyngeal instillation of MWCNT. Lungs were harvested at 3, 10, 20, and 60 days post instillation for evaluation of MMP12 expression and granulomatous changes. Bronchoalveolar lavage (BAL) cells were analyzed 60 days after MWCNT instillation for expression of mediators thought to play a role in sarcoid granulomatosis: peroxisome proliferator-activated receptor-gamma (PPARγ), interferon-gamma (IFN-γ), and CCL2 (MCP-1).

Results

Pulmonary granuloma appearance at 10 days after MWCNT instillation showed no differences between wildtype and Mmp12 KO mice. In contrast, by 60 days after MWCNT instillation, Mmp12 KO mice revealed markedly attenuated granuloma formation together with elevated PPARγ and reduced IFNγ expression in BAL cells compared to wildtype. Unexpectedly, Mmp12 KO mice further demonstrated increased alveolar macrophages with increased CCL2 at 60 days.

Conclusions

The striking reduction of granuloma formation at day 60 in Mmp12 KO mice suggests that MMP12 is required to maintain chronic granuloma pathophysiology. The increased PPARγ and decreased IFNγ findings suggest that these mediators also may be involved since previous studies have shown that PPARγ suppresses IFNγ and PPARγ deficiency amplifies granuloma formation. Interestingly, a role of MMP12 in granuloma resolution is also suggested by increases in both macrophage influx and CCL2. Overall, our results strongly implicate MMP12 as a key factor in granuloma persistence and as a possible therapeutic target in chronic pulmonary sarcoidosis.

⁹⁹mTc-anti-TNF-α antibody for the imaging of disease activity in pulmonary sarcoidosis

Infliximab, a monoclonal antibody directed against tumour necrosis factor (TNF)-α, is used in the treatment of refractory sarcoidosis. However, the clinical response is variable and a tool to select responders beforehand is highly desirable. In this study we evaluated scintigraphy with technetium-99m ((99m)Tc)-labelled infliximab for the imaging of disease activity in patients with pulmonary sarcoidosis.10 patients were studied using single photon emission computed tomography/computed tomography (CT) 6 h and 20 h after intravenous administration of 370 MBq of(99m)Tc-infliximab. Correlation analysis was performed between tissue accumulation of(99m)Tc-infliximab and laboratory parameters (including soluble interleukin-2 receptor and angiotensin-converting enzyme), lung function parameters (including forced expiratory volume in 1 s and the diffusing capacity of the lung for carbon monoxide) and(18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT.Analysis showed selective and variable accumulation of(99m)Tc-infliximab in the target tissue. Accumulation correlated positively with all four laboratory parameters and negatively with all four lung function parameters, yielding better correlations than serum TNF-α levels or(18)F-FDG PET/CT.(99m)Tc-infliximab accumulation reflects thein situTNF-α expression in an individual patient and therefore provides valuable information on the presence of the biological target for anti-TNF-α therapy.

Differential inflammatory microRNA and cytokine expression in pulmonary sarcoidosis

Sarcoidosis is a granulomatous disease of unknown etiology. The disease has an important inflammatory and immune component; however, its immunopathogenesis is not completely understood. Recently, the role of microRNAs (miRNAs), the small non-coding RNAs, has attracted attention as both being involved in pathogenesis and serving as disease markers. Accordingly, changes in the expression of some miRNAs have been also associated with different autoimmune pathologies. However, not much is known about the role of miRNAs in sarcoidosis. Therefore, the aim of this study was to compare the level of expression of selected miRNAs in healthy individuals and patients with sarcoidosis. We detected significantly increased level of miR-34a in peripheral blood mononuclear cells isolated from sarcoidosis patients. Moreover, significantly up-regulated levels of interferon (IFN)-γ, IFN-γ inducible protein (IP-10) and vascular endothelial growth factor were detected in sera of patients when compared to healthy subjects. Our results add to a known inflammatory component in sarcoidosis. Changes in the levels of miR-34a may suggest its involvement in the pathology of this disease.

Ferrous ferric chloride downregulates the inflammatory response to Rhodococcus aurantiacus infection in mice

The healthy drink Pairogen is mainly composed of ferrous ferric chloride water that reportedly changes the status of intracellular water from oxidative to antioxidative. Here, we investigated whether Pairogen affects host immune function in a murine model of granulomatous inflammation in response to Rhodococcus aurantiacus (R. aurantiacus) infection. Longitudinal ingestion of Pairogen markedly improved the survival of infected mice in a concentration-dependent manner. Compared to mice received water, mice that ingested 10-fold-diluted Pairogen displayed rapid bacterial elimination, decreased production of tumor necrosis factor (TNF)-α and interleukin (IL)-6, and high levels of IL-10 in organs during the initial phase of infection. Moreover, histological studies showed significant reduction in the number and size of granulomas as well as amelioration of oxidative stress in the livers of mice ingested 10-fold-diluted Pairogen at 14 d post-infection. These characteristics were further pronounced in first-generation (F1) mice that also ingested 10-fold-diluted Pairogen. Following stimulation with heat-killed R. aurantiacus, the production of TNF-α, IL-6, and IL-10 by macrophages from F1 mice was similar to that detected in vivo, while their gene expression levels in these cells were significantly lower than the levels in macrophages from mice received water. Heat-killed R. aurantiacus also induced the expression of heme oxygenase-1 mRNA in the cells from F1 mice. Taken together, these results indicate that Pairogen contributes to the negative regulation of the immuno-inflammatory response to R. aurantiacus infection in mice by modulating the cellular redox state. Longitudinal ingestion of Pairogen further enhances the defense function in mouse progeny.

Elevated expression of interleukin-18 in the granulomatous lesions of muscular sarcoidosis

In an attempt to understand the role of interleukin-18 (IL-18) in the pathogenesis of sarcoidosis, we examined the expression of IL-18 in normal muscle and in muscle biopsies from six patients with muscular sarcoidosis. Western blot analysis demonstrated that IL-18 was identified only in homogenates of granulomatous muscle tissues, but not in normal muscle tissue homogenates. By immunohistochemistry, strongly IL-18-positive cells were distributed predominantly at the boundary zone of the granulomas. They were recognized as activated macrophages by double staining with anti-CD68. Epithelioid cells showed only faint reactivity. Serum IL-18 levels of patients with sarcoidosis were significantly increased compared to those of healthy volunteers. Unlike protein expression, IL-18 mRNA expression was detected even in normal muscles. Our results coupled with those of previous investigations demonstrating activity of IL-18 in inducing interferon-gamma production suggest a significant role of IL-18 in the pathogenesis of sarcoidosis.

Transcriptional regulation of the human interleukin 1beta gene by fibronectin: role of protein kinase C and activator protein 1 (AP-1)

Interleukin 1beta (IL-1beta) is a multifunctional polypeptide considered a key cytokine during inflammation. Fibronectin (FN), a matrix glycoprotein highly expressed in injured tissues, can induce expression of IL-1beta in human blood monocytic cells. Herein, we explore the intracellular signals and transcriptional mechanisms responsible for IL-1beta induction by FN using human promonocytic U937 cells transfected with the human IL-1beta promoter connected to a reporter gene. Exposure of transfected U937s to FN resulted in increased expression of the full-length IL-1beta promoter. This effect, mediated via the alpha5beta1 integrin, was associated with activation of mitogen-activated protein kinases (MAPKs) and was abolished by pre-treatment of cells with Calphostin C, a specific inhibitor of protein kinase C (PKC) activation. Deletion analysis and co-transfection studies using consensus activator protein 1 (AP-1) oligonucleotides suggested that an AP-1 site present in the 5' end of the IL-1beta promoter was involved in the FN-induced response. Finally, electrophoretic mobility shift assays showed that FN induced binding of AP-1, but not NF-kappaB. Together, these experiments demonstrate that FN binding to the alpha5beta1 integrin activates MAPK-dependent signal pathways, and results in the transcription of the IL-1beta promoter in U937 cells by activating PKC and inducing AP-1.

Increased levels of interleukin-18 in patients with pulmonary sarcoidosis

Interleukin-18 (IL-18) has recently been identified as an interferon-gamma (IFN-gamma)-inducing factor, and it plays an important role in T helper 1 (Th1) response. We measured the serum levels of IL-18 and IFN- gamma in 37 patients with pulmonary sarcoidosis and 25 healthy control subjects. We also measured the levels of IL-18 and IFN-gamma in 10-fold concentrated bronchoalveolar lavage (BAL) fluids of 19 patients with pulmonary sarcoidosis and 9 healthy control subjects (all lifelong nonsmokers). The levels of serum IL-18 and IFN-gamma were significantly increased in patients with sarcoidosis. The levels of BAL fluid IL-18 were significantly elevated in patients with sarcoidosis, however, the IFN-gamma levels of the patients and control subjects were all below sensitivity. Serum IL-18 levels significantly correlated with serum IFN-gamma levels and lysozyme activity. The patients positive for gallium-67 ((67)Ga) scan had significantly elevated serum IL-18 levels as compared with those of the negative patients. BAL fluid IL-18 levels significantly correlated with serum IL-18 levels in patients with sarcoidosis, and there was a significant correlation between IL-18 levels and lymphocyte proportions in sarcoid BAL fluids. In patients with sarcoidosis, IL-18 seems to induce IFN-gamma production and IL-18 levels in sera may reflect disease activity of sarcoidosis.

Necrobiotic cutaneous T-cell lymphoma

We report 3 patients with granulomatous cutaneous T-cell lymphoma (CTCL) who showed necrobiosis histologically with palisading granulomas. Although granulomatous change may be present in up to 4% of cases of CTCL, necrobiosis is rare. Misdiagnosis may occur if epidermotropism is minimal or if atypical cells are masked by the granulomatous infiltrate. T-cell receptor gene analysis confirmed the presence of clonal T-cell populations in lesional skin from all 3 cases.

Bullous sarcoidosis: a report of three cases

Three cases of pulmonary sarcoidosis presented as bullous emphysema with severe airflow obstruction, and the diagnosis of sarcoidosis was unsuspected for at least 2 years. Potential mechanisms of bullous emphysema from sarcoidosis are discussed. The physician should suspect sarcoidosis as the cause of bullous emphysema when young patients who have smoked relatively few pack-years present with emphysema or severe airflow obstruction. Additional clues are the presence of mediastinal adenopathy on a chest radiograph or a CT scan and a history consistent with extrapulmonary sarcoidosis.

Taming TNF: strategies to restrain this proinflammatory cytokine

Recent studies have demonstrated the essential role of tumor necrosis factor alpha (TNF-alpha) in rheumatoid arthritis and Crohn's disease. This article discusses agents known to suppress the formation or activity of TNF-alpha, and summarizes clinical studies using anti-TNF-alpha antibodies.

Reciprocal action of interferon-gamma and interleukin-4 promotes granulomatous inflammation induced by Rhodococcus aurantiacus in mice

An intravenous injection of Rhodococcus aurantiacus to mice causes granulomatous inflammation dependent on endogenous interferon-gamma (IFN-gamma). The present study examined the role of endogenous interleukin-4 (IL-4) on granulomatous inflammation. Endogenous IL-4 in the spleen extracts was not detected during the phase of granuloma formation by enzyme-linked immunosorbent assay (ELISA). However, IL-4 protein level was elevated during the phase of granuloma regression. IL-4 mRNA expression in the livers and spleens was also elevated during the phase of granuloma regression. In addition, IL-4 levels during the phase of granuloma formation were increased by treatment with anti-IFN-gamma monoclonal antibody (mAb), suggesting that endogenous IFN-gamma might inhibit IL-4 production during the phase of granuloma formation. Administration of anti-IL-4 mAb on weeks 3 and 4 after the inoculation inhibited the regression of granulomas and augumented IFN-gamma level at 5 weeks. Endogenous IFN-gamma was produced by CD4+ T cells during the phase of granuloma regression and endogenous IL-4 was produced by both CD4+ and CD8+ T cells. These findings suggest that during the phase of granuloma formation endogenous IL-4 might be inhibited by IFN-gamma, while during the phase of granuloma regression endogenous IL-4 might play a crucial role in the reduction of granulomas and IFN-gamma production.

CD7-positive Sézary syndrome with a Th1 cytokine profile

Sézary syndrome is a leukemic variant of cutaneous T-cell lymphoma characterized by the appearance of numerous CD4+ cells with cerebriform nuclei in the peripheral blood. Recent observations have suggested that Sézary cells lack CD7 molecules on their surface and are analogous to murine Th2 cells. It remains unclear, however, whether these two properties are actually common features of Sézary cells. We describe a case of Sézary syndrome in which more than 98% of the peripheral blood mononuclear cells expressed CD7 as well as a homogeneous T-cell receptor V alpha 2V beta 17, indicative of the expression of CD7 in the Sézary cells. Although the circulating Sézary cells continuously bore CD7 molecule on their surface throughout the patient's clinical course, the intensity of CD7 expression was variable in skin-infiltrating and in vitro cultured cells. Peripheral blood mononuclear cells from the patient proliferated well to a V beta 17-relevant superantigen (staphylococcal enterotoxin B) but not to irrelevant superantigens; produced interleukin-2, interferon gamma, and tumor necrosis factor-alpha, but not interleukin-4; and transcribed messenger RNA for interleukin-2 and interferon gamma but not interleukin-4 or interleukin-10. This represents an unusual case of a CD7+ Sézary syndrome with a cytokine profile characteristic of Th1 cells.

Presence of mRNA for interferon-gamma (IFN-gamma) in blood mononuclear cells is associated with an active stage I sarcoidosis

Peripheral blood mononuclear cells (PBMC) and bronchoalveolar lavage (BAL) cells obtained from sarcoidosis patients were investigated for the presence of mRNA for IFN-gamma. RNA was extracted from freshly obtained cells. In 12 cases PBMC were studied and in seven cases BAL cells were also available for concomitant investigation. In eight patients mRNA for IFN-gamma was present in blood and was significantly associated with stage I disease (P = 0.030). By comparison, BAL cells were less frequently positive for IFN-gamma transcripts (P = 0.039). Only one patient had simultaneous expression of IFN-gamma gene in blood and BAL cells. All other patients including four positive in blood were negative in BAL. The presence of IFN-gamma transcripts in PBMC was significantly associated with the capacity of these cells to generate IFN-gamma in unstimulated cultures. PBMC from patients showing IFN-gamma mRNA in blood were frequently high IFN-gamma producers in anti-CD3 MoAb-stimulated cultures.

Clonal analysis of lung and blood T cells in patients with sarcoidosis

BACKGROUND

Sarcoidosis is a disease characterised by clinical "anergy" to delayed type hypersensitivity antigens and the formation of non-caseating granulomas, which frequently manifests in the lungs as a T lymphocyte/mononuclear cell alveolitis. Although there is an increased proportion of T cells in bronchoalveolar lavage (BAL) samples from these patients, and these T cells often show evidence of activation and spontaneous secretion of cytokines such as interleukin 2 (IL-2) and interferon gamma (IFN gamma)--a pattern similar to delayed type hypersensitivity reactions--it is unclear whether both cytokines are produced by the majority of T cells derived from the lungs of patients with sarcoidosis or whether unique subpopulations of T cells produce each cytokine. In this study the properties of T cells cloned from BAL fluid samples of patients with sarcoidosis have been analysed.

METHODS

T cells were cloned by limiting dilution using IL-2, phytohaemagglutinin, and irradiated feeder cells. Cloning efficiencies were compared and phytohaemagglutinin induced clonal production of IL-2, IFN gamma, and IL-4 was determined by bioassay (IL-2 and IFN gamma) or ELISA (IL-4).

RESULTS

T cells derived from the BAL fluid of patients with sarcoidosis cloned less efficiently than those from blood of the same individuals. Lung derived clones (CD4+ or CD8+) produced IFN gamma more frequently and to a higher titre than blood derived clones, whereas IL-2 production by CD4+ clones derived from BAL fluid was less than that from blood derived clones. Interestingly, IL-4 production by clones from both sites was similar. Analysis of the co-production of IL-2, IFN gamma, and IL-4 by these BAL fluid clones did not demonstrate a predominant "Th1"-like population which has been suggested to underlie delayed type hypersensitivity reactions.

CONCLUSIONS

The reduced cloning efficiency of T cells from the lung compared with the blood in sarcoidosis is consistent with, although probably more pronounced than, previous observations in normal lungs and shows that T cell hyporesponsiveness is not overcome in the lungs of patients with sarcoidosis. Furthermore, major differences exist between the cytokine producing potential of T cells derived from the lung and the blood in sarcoidosis, and these parallel the differences in the properties of blood and lung T cells seen in healthy individuals.

Circulating adhesion molecules in sarcoidosis

Sarcoidosis is a disease of unknown etiology characterized by non-caseating granulomata together with a number of systemic abnormalities. We have recently shown these include increased expression of the integrins CD11/CD18 on peripheral blood leucocytes. Here we have measured serum levels of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) in 23 patients and 14 normal controls using antigen capture sandwich ELISAs. Median circulating E-selectin levels in the patients were nearly three times those of the controls (P < 0.0001, Mann-Whitney U-test), whilst ICAM-1 but not VCAM-1 levels were only slightly elevated. These results show that endothelial cell activation and shedding of E-selectin into the circulation are additional features of the pathology of sarcoidosis.

Oligo-2',5'-adenylate synthetase in pulmonary sarcoidosis and idiopathic pulmonary fibrosis

Oligo-2',5'-adenylate synthetase (2,5AS) is an enzyme induced by all types of interferon (IFN). We measured the levels of 2,5AS activity in peripheral blood mononuclear leukocytes (PBML) and bronchoalveolar lavage fluid (BALF) cells of patients with pulmonary sarcoidosis (SAR), idiopathic pulmonary fibrosis (IPF), and normal controls (NC). In NC, the levels of BALF cell 2,5AS activity were approximately seven times as high as the levels of PBML 2,5AS activity. The measurement 2,5AS activity from isolated cells showed that the levels of 2,5AS activity are independent of cell differential from PBML and BALF cells. The levels of PBML and BALF cell 2,5AS activity in SAR were both significantly high in comparison with those in NC. In patients with IPF, the levels of PBML 2,5AS activity were significantly increased as compared with those in NC, whereas there was no significant difference regarding the levels of BALF cell 2,5AS activity between patients with IPF and NC. These results suggest the following: (1) in patients with SAR, IFN production is enhanced both in the alveolar space and peripheral circulation; (2) in patients with IPF, IFN production is greatly enhanced in the circulation, whereas IFN production is not enhanced in the alveolar space; and (3) IFN may contribute to the pathogenesis of SAR and IPF.

Soluble intercellular adhesion molecule-1 (ICAM-1) in sera and bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis

ICAM-1 plays an important role in inflammatory diseases. To assess level of soluble ICAM-1 in the circulation and inflamed lesions, we measured levels of soluble ICAM-1 in the circulation and bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF) and with pulmonary sarcoidosis (PS) and of healthy volunteers (HV), and we also analysed ICAM-1 expression of BALF cells in some patients and HV. IPF patients had significantly higher levels of circulating ICAM-1 than HV, while PS patients did not. By contrast, significantly increased levels of BALF soluble ICAM-1 were found in PS patients compared with those of HV, but not in IPF patients. There were no significant differences in the proportions of ICAM-1+ BALF lymphocytes in IPF patients, PS patients and HV, whereas significantly increased proportions of ICAM-1+ pulmonary alveolar macrophages were found in PS patients compared with those of HV, but not in IPF patients. There was a significant positive correlation of BALF soluble ICAM-1 levels to BALF lymphocyte proportions in PS patients. Although the source of BALF soluble ICAM-1 is unclear, BALF soluble ICAM-1 appears to reflect the grade of local activity of sarcoidosis. An interesting discrepancy between soluble ICAM-1 levels in the circulation and BALF was found in IPF patients, and this might be an important clue to an understanding of this disorder.

Somatostatin and the lung

Lung carcinoma is the most common cause of death in the western world and is increasing particularly among women. Despite significant developments in our understanding of the molecular biology of this disease our ability to treat the various subtypes of lung cancer has been at a relative standstill for the past decade. Novel approaches to the therapy of lung tumours are required. Recent work has evaluated the potential role of somatostatin and its analogues in the treatment of lung cancer. Experimental evidence has demonstrated that lung tumours, in particular small cell lung cancer (SCLC), may express somatostatin. The significance of this expression has not yet been evaluated. Somatostatin receptors have been demonstrated on between 50-75% of SCLC cell lines and fresh tumour samples studied to date. Using radiolabelled somatostatin analogues SCLC tumours may be detected and localised in patients through scintigraphic imaging techniques. Studies have shown that SCLC cell line clonal proliferation may be inhibited in vitro with somatostatin analogues suggesting that the somatostatin receptors are functional. In-vivo growth inhibition studies have likewise yielded encouraging results with growth inhibition of somatostatin receptor positive SCLC xenografts and receptor negative SCLC and non-small cell lung cancer cell line xenografts. These latter result suggests that somatostatin analogues may inhibit tumour growth by indirect as well as direct means. These findings have laid the ground for formal clinical trials in the future.

Endogenous gamma interferon is essential in granuloma formation induced by glycolipid-containing mycolic acid in mice

The present study examined the role of endogenous gamma interferon (IFN-gamma) in the formation of granulomas in mice which had been given a single intravenous injection of glycolipid-containing mycolic acid (trehalose 2,3,6'-trimycolate) purified from cell walls of Rhodococcus aurantiacus (Gordona aurantiaca) (GaGM) in the form of liposome. The histological status of granuloma formation in the livers, spleens, and lungs of GaGM-injected mice was studied at weeks 1 through 5, and the titers of endogenous IFN-gamma in all of these organ extracts and in the sera were determined by enzyme-linked immunosorbent assay. The granulomas, composed of epithelioid cells, developed until 3 weeks postinjection, and thereafter the granulomas regressed. The production of endogenous IFN-gamma was biphasic, with an early phase detected at days 1 through 3 and a late phase detected at weeks 1 through 5. The latter peak of endogenous IFN-gamma production proceeded in parallel with granuloma formation. Both the areas of granulomas and titers of IFN-gamma in these organs were dependent on the doses of GaGM used for injection. The cells which produce endogenous IFN-gamma in the spleens appear within the granulomas. To study the role of endogenous IFN-gamma in granuloma formation, the in vivo administration of rat anti-mouse IFN-gamma monoclonal antibody was carried out. Anti-mouse IFN-gamma monoclonal antibody neutralized endogenous IFN-gamma and resulted in the suppression of the number of granulomas and the size of each granuloma. These findings suggest that biphasic production of endogenous IFN-gamma in the local lesions may be crucial to the formation and development of the granulomas.

Increased CD11/CD18 expression on peripheral blood leucocytes of patients with sarcoidosis

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomata, formed mainly from macrophages surrounded by lymphocytes and plasma cells. Using a novel method for the preparation of blood leucocytes for flow cytometry, we report increased expression of LeuCAMs (CD11/CD18) on peripheral blood leucocytes of 11 Caucasian and 10 Afro-Caribbean patients with sarcoidosis compared with age-, sex- and race-matched controls. Whilst the percentages of the cells expressing CD11/CD18 were no different, the density, expressed as mean fluorescence intensity (MFI), was greater for all leucocytes in sarcoids than in normal individuals. The expression of intercellular adhesion molecule-1 (ICAM-1), a ligand for LFA-1 which is expressed on all leucocytes, was not significantly different from normal, whereas HLA-DR was expressed more intensely on sarcoid monocytes (P less than 0.01) and blood lymphocytes (P less than 0.005) than control cells. Our findings are consistent with leucocyte activation although we were unable to confirm reports of elevated tumour necrosis factor-alpha (TNF-alpha) in the patients' plasma using an ELISA. Increased expression of adhesion molecules on peripheral blood leucocytes may play a role in the cellular extravasation, aggregation, and granuloma formation seen in sarcoidosis.

CD4 antibody treatment in Crohn's disease

Immunologic changes may play a role in the pathogenesis of Crohn's disease. Whether these changes are the primary cause of the disease or secondary to the inflammatory response remains unknown. Activated T helper cells probably play a pivotal role in Crohn's disease, although no causative antigen has been identified. Possible targets for immunomodulating therapy should include neutralization of the antigens, deletion of reactive activated T cells or, less specifically, interference with the antigen-presenting process. New, humanized, monoclonal antibodies that interfere with the antigen-presenting process are now available for clinical investigation. In particular, CD4 antibody treatment seems of interest, in view of the predominant role of T cells in Crohn's disease. Finally, because tumor necrosis factor is necessary for granuloma formation, inhibition of this factor may be expected to improve disease activity in Crohn's disease.