Granulomatous Inflammation In Sarcoidosis Research Articles

Discovery of Two Novel Immunoepitopes and Development of Peptide-based Sarcoidosis Immunoassay.

Sarcoidosis is a systemic granulomatous disorder associated with hypergammaglobulinemia and the presence of autoantibodies. The specific antigens initiating granulomatous inflammation in sarcoidosis are unknown and there is no specific test available to diagnose sarcoidosis. To discover novel sarcoidosis antigens, we developed a high-throughput T7 phage display library derived from the sarcoidosis cDNA and identified numerous clones differentiating sarcoidosis from other respiratory diseases. After clone sequencing and homology search, we identified two epitopes (Cofilinμ and Chain A) that specifically bind to serum IgGs of sarcoidosis patients. To develop and validate an epitope-specific IgG-based immunoassay specific for sarcoidosis. We chemically synthesized both immunoepitopes (Cofilinμ and Chain A), and generated rabbit polyclonal antibodies against both neoantigens. After extensive standardization, we developed a direct peptide ELISA and measured epitope-specific IgG in sera of 386 subjects including, healthy controls (n=100), three sarcoidosis cohorts (n=186), pulmonary tuberculosis (n=70) and lung cancer (n=30). To develop a model to classify sarcoidosis from other groups, data were analyzed using five-fold cross-validation when adjusting for confounders. The Cofilinμ IgGs model yielded a mean sensitivity, specificity, and positive and negative predictive value (PPV, NPV) of 0.97, 0.9, 0.9 and 0.96, respectively. Those same measures for Chain A IgG antibody were 0.9, 0.83, 0.84 and 0.9 respectively. Combining both biomarkers improved AUC, sensitivity, specificity, PPV and NPV. These results provide a novel immunoassay for sarcoidosis. The discovery of two neoantigens facilitates the development of biospecific drug discovery and the sarcoidosis-specific model.

Identification of CD14 and lipopolysaccharide-binding protein as novel biomarkers for sarcoidosis using proteomics of serum extracellular vesicles.

Sarcoidosis is a complex, polygenic, inflammatory granulomatous multi-organ disease of unknown cause. The granulomatous inflammation in sarcoidosis is driven by the interplay between T cells and macrophages. Extracellular vesicles (EVs) play important roles in intercellular communication. We subjected serum EVs, isolated by size exclusion chromatography, from seven patients with sarcoidosis and five control subjects to non-targeted proteomics analysis. Non-targeted, label-free proteomics analysis detected 2292 proteins in serum EVs; 42 proteins were up-regulated in patients with sarcoidosis relative to control subjects; and 324 proteins were down-regulated. The protein signature of EVs from patients with sarcoidosis reflected disease characteristics such as antigen presentation and immunological disease. Candidate biomarkers were further verified by targeted proteomics analysis (selected reaction monitoring) in 46 patients and 10 control subjects. Notably, CD14 and lipopolysaccharide-binding protein (LBP) were validated by targeted proteomics analysis. Up-regulation of these proteins was further confirmed by immunoblotting, and their expression was strongly increased in macrophages of lung granulomatous lesions. Consistent with these findings, CD14 levels were increased in lipopolysaccharide-stimulated macrophages during multinucleation, concomitant with increased levels of CD14 and LBP in EVs. The area under the curve values of CD14 and LBP were 0.81 and 0.84, respectively, and further increased to 0.98 in combination with angiotensin-converting enzyme and soluble interleukin-2 receptor. These findings suggest that CD14 and LBP in serum EVs, which are associated with granulomatous pathogenesis, can improve the diagnostic accuracy in patients with sarcoidosis.

A Sarcoidosis Case With Galaxy Sign Admitted With A Rare Symptom : Hemoptysis

30 year-old male patient applied to hospital with complaint of hemoptysis. 30 year-old male patient applied to hospital with complaint of hemoptysis. Bilateral extensive nodular infiltrations and mediastinal lymphadenopathies were detected. Wedge resection and parietal pleura biopsy were performed for the patient. The pathology report indicated that the case should be further examined from the aspect of granulomatous diseases, especially the sarcoidosis. The diagnosis was made as galaxy sign of sarcoidosis. Hemoptysis is a rare symptom seen in sarcoidosis. The hemoptysis is observed at advanced stage of sarcoidosis and in presence of cavity in sarcoidosis. There is no study in literature regarding the initial complaint of hemoptysis in sarcoidosis case, for whom the galaxy appearance was observed radiologically. Here, we present the etiological causes of granulomatous inflammation in sarcoidosis with non-typical clinic and radiology.

A 62-Year-Old African American Woman With Stable Lymphadenopathy Over 5 Years

Abstract The patient is a 62-year-old African American female with medical history of Plummer Vinson syndrome and CT scan in 2014 showing lymphadenopathy of the porta hepatis. Needle core biopsy of enlarged lymph nodes revealed sheets of polytypic plasma cells with no aberrant B or T cells or granulomas or hyaline-like depositions identified. The findings were suspicious for unicentric Castleman disease. In 2019, the patient presented with chronic fatigue without other systemic symptoms. Contrast CT revealed persistent retroperitoneal lymphadenopathy and calcified granulomas in the liver, spleen, and lung. Excision of portal and celiac nodes showed preserved nodal architecture with mild mantle zone expansion and marked hyaline-like deposition in the follicles. Sheets of mature plasma cells and focally increased vasculatures were seen in the interfollicular areas. Focally frequent nonnecrotizing granulomas were noted. Occasional giant cells and rare asteroid bodies were identified in the granulomas. Immunohistochemistry stain workup revealed normal distribution of the B and T lymphocytes. CD138 stain highlighted marked increased plasma cells and HHV8 was negative. Immunofluorescence microscopy for kappa and lambda did not show monoclonality; IgA was positive in <10% of plasma cells; special stain for Congo red and serum amyloid associated protein (SSA) IHC stain were strongly positive in the follicles. The overall findings are consistent with reactive lymphadenopathy with interfollicular polytypic plasmacytosis, noncaseating granuloma formation, and reactive amyloidosis. The features of mantle zone hyperplasia and polytypic plasmacytosis are suggestive of HHV8-negative/idiopathic unicentric Castleman disease. This case possibly represents an example of concurrent amyloidosis, sarcoidosis, and idiopathic unicentric Castleman disease. Given that SSA was recently reported to have a pathogenic role in granulomatous inflammation of sarcoidosis through sustained inflammatory reaction, the possibility of increased SSA triggering sarcoidoisis in this patient can be considered. However, the exact pathogenesis of these concurrent findings needs further investigation and clarification.

Metabolomics connects aberrant bioenergetic, transmethylation, and gut microbiota in sarcoidosis.

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Granulomatous inflammation in sarcoidosis may affect multiple organs, including the lungs, skin, CNS, and the eyes, leading to severe morbidity and mortality. The underlying mechanisms for sustained inflammation in sarcoidosis are unknown. We hypothesized that metabolic changes play a critical role in perpetuation of inflammation in sarcoidosis. 1H nuclear magnetic resonance (NMR)-based untargeted metabolomic analysis was used to identify circulating molecules in serum to discriminate sarcoidosis patients from healthy controls. Principal component analyses (PCA) were performed to identify different metabolic markers and explore the changes of associated biochemical pathways. Using Chenomx 7.6 NMR Suite software, we identified and quantified metabolites responsible for such separation in the PCA models. Quantitative analysis showed that the levels of metabolites, such as 3-hydroxybutyrate, acetoacetate, carnitine, cystine, homocysteine, pyruvate, and trimethylamine N-oxide were significantly increased in sarcoidosis patients. Interestingly, succinate, a major intermediate metabolite involved in the tricyclic acid cycle was significantly decreased in sarcoidosis patients. Application of integrative pathway analyses identified deregulation of butanoate, ketone bodies, citric cycle metabolisms, and transmethylation. This may be used for development of new drugs or nutritional modification.

Efficacy and Safety of Conventional Transbronchial Needle Aspiration in Sarcoidosis: A Systematic Review and Meta-analysis

Flexible bronchoscopic procedures are currently the most often employed technique for demonstrating granulomatous inflammation in sarcoidosis. Conventional transbronchial needle aspiration (TBNA) has been used for over 3 decades; however, it remains an underutilized technique, primarily due to the wide variations in the reported success rates and unconfirmed safety concerns. Herein we perform a systematic review and meta-analysis of studies to estimate the diagnostic yield and safety of TBNA in sarcoidosis. We searched the PubMed and EmBase databases for studies (1980 to January 2012) reporting the efficacy of TBNA in sarcoidosis. The quality of studies was assessed using the QualSyst tool. The efficacy of TBNA in individual studies was calculated as proportions and 95% CIs, and the results were pooled using a random effects model. Heterogeneity and publication bias were assessed for the individual outcomes. Our search yielded 21 studies (915 patients). The diagnostic yield of TBNA ranged from 6-90%, with the pooled efficacy being 62% (95% CI 52-71%) by the random effects model. TBNA was not associated with any major complication. The diagnostic yield increased to 83% if transbronchial lung biopsy (TBLB) was additionally performed, albeit with increased complications. There was evidence of heterogeneity and publication bias, which significantly decreased on sensitivity analysis after exclusion of retrospective studies. TBNA is an efficacious and safe procedure in the diagnosis of sarcoidosis. The performance of TBLB adds to the efficacy of TBNA. Hence, a combination of TBNA and TBLB should be routinely employed in diagnosis of sarcoidosis in those with enlarged mediastinal lymph nodes.

7T Brain MR Imaging of Neurosarcoidosis: Preliminary Observations (S08.006)

Objective: To describe imaging characteristics of neurosarcoidosis on unenhanced 7T MRI. Background Non-caseating granulomatous inflammation in sarcoidosis is characterized by organized collections of mononuclear phagocytes, cells that are known to sequester microscopic quantities of calcium, iron and ferritin. We hypothesized that 7 tesla MR phase imaging, due to its high spatial resolution, sensitivity to these compounds, and ability to visualize tiny venous structures, would reveal novel features of neurosarcoidosis not currently visualized using 3T MRI. Design/Methods: Pilot study of 7T MRI in patients with neurosarcoidosis. Diagnosis was established by confirmatory biopsy of CNS tissue or extra-CNS tissue in patients with an otherwise typical neurological syndrome. Participants underwent imaging on a 7T GE scanner using a 2D T2*-weighted gradient echo sequence at 190 x 260 micron in-plane resolution (TR/TE=250/12 msec, 20 degree flip angle, 2 mm slice thickness, 3 signal averages). Magnitude and unwrapped phase images were generated from the raw image data using in-house software. Results: 7T MRI was performed in six patients with CNS sarcoidosis, 3 with definite disease and 3 with probable disease (the latter established by mediastinal/lung biopsy). All participants were on immunosuppressive therapy at time of imaging, and four had active disease at the time 7T MRI was performed. Three distinctive imaging features emerged: 1) several enhancing lesions at 3T were seen as T2* hypointense nodules on 7T images; 2) lesions seen on 3T T2-weighted sequences tended to spread across multiple veins in the white matter on 7T, rather than a single vein; 3) perimedullary veins on 7T sometimes appeared distorted in regions that corresponded to areas of meningeal and perivascular enhancement on 3T. These features differ in several respects from initial reports of 7T MRI of demyelinating plaques in MS. Conclusions: Active neurosarcoidosis lesions exhibit distinctive features on 7T MRI that may assist in noninvasive diagnosis. Supported by: American Academy of Neurology Clinical Research Training Fellowship (JMG). Disclosure: Dr. Gelfand has received personal compensation in an editorial capacity for Journal Watch Neurology. Dr. Green has received personal compensation for activities with Novartis and Biogen Idec as a consultant and/or participant on an advisory board and adjudication committee. Dr. Hess has nothing to disclose.

Analysis of serum amyloid A in sarcoidosis patients

A crucial pathogenetic role of serum amyloid A (SAA) in granulomatous inflammation of sarcoidosis has recently been reported. In this study we analyzed SAA expression in detail, starting from proteomic analysis of serum of sarcoidosis patients. We also used the faster ELISA method that enabled us to examine a greater number of samples. Serum concentrations of SAA were significantly higher in sarcoidosis patients than controls (p<0.001), inversely correlated with FEV(1) and significantly higher in patients with subacute onset requiring prolonged and multiple steroid treatments (class 6 SCAC) than in patients with subacute onset not requiring therapy (class 4 SCAC) (p<0.001). Our results suggest that serum amyloid A could be a suitable marker of sarcoidosis: its serum concentrations are significantly higher in sarcoidosis patients than controls, the protein is only expressed in gels of sarcoidosis patients and not in healthy subjects, and the SAA1 isoforms could match the unidentified biomarker of sarcoidosis reported in a previous proteomic study by another group. The effectiveness of SAA as a clinical biomarker of sarcoidosis should now be investigated in a large prospective study.

POI17 Dramatic radiological improvement in isolated neurosarcoidosis treated with infliximab

We report a case of a 44-year-old woman with isolated neurosarcoidosis with florid craniospinal leptomeningeal enhancement. Her main symptoms of headache, diplopia, ataxia and perineal numbness failed to respond to...

Pro: The treatment of the granulomatous response is beneficial in acute sarcoidosis

Corticosteroids effectively suppress granulomatous inflammation in sarcoidosis. However, the role of corticosteroids remains unsettled nearly sixty years after the first report of their benefits. As in other contentious areas of medicine, we prioritize evidence from controlled clinical trials to guide decision-making. Despite the paucity of randomized, double-blind controlled evidence, the preponderance of data from the available trials is congruent: treatment of acute sarcoidosis is “on-balance” beneficial. To provide focus, I will limit my comments to recent-onset pulmonary sarcoidosis, defined as less than five years since diagnosis.

Treatment of Sarcoidosis

Sarcoidosis is an immune-mediated systemic syndrome of unknown etiology. The treatment of the granulomatous inflammation in sarcoidosis is thus dependent on nonspecific suppression of the immune response. Although steroid-sparing approaches have moved to front-line therapy for many other immune-mediated inflammatory diseases, corticosteroids remain the initial treatment of choice for most patients with sarcoidosis due in large part to the clinical variability and high rates of spontaneous remission. Given the heterogeneity of clinical phenotypes between patients, treatment approaches must be individualized. For patients with persistent disease, or for patients who are intolerant of systemic steroids, there are several steroid-sparing immune-modulating medications that have been effective for treating sarcoidosis. Besides immunosuppressives, we will also overview several sarcoidosis-related issues that contribute to patient-reported symptoms, a "sarcoidosis penumbra." Recognition and judicious therapy for these related issues are often key to optimizing outcomes and quality of life.

Serum Amyloid A Regulates Granulomatous Inflammation in Sarcoidosis through Toll-like Receptor-2

The critical innate immune mechanisms that regulate granulomatous inflammation in sarcoidosis are unknown. Because the granuloma-inducing component of sarcoidosis tissues has physicochemical properties similar to those of amyloid fibrils, we hypothesized that host proteins capable of forming poorly soluble aggregates or amyloid regulate inflammation in sarcoidosis. To determine the role of the amyloid precursor protein, serum amyloid A, as an innate regulator of granulomatous inflammation in sarcoidosis. Serum amyloid A expression was determined by immunohistochemistry in sarcoidosis and control tissues and by ELISA. The effect of serum amyloid A on nuclear factor (NF)-kappaB induction, cytokine expression, and Toll-like receptor-2 stimulation was determined with transformed human cell lines and bronchoalveolar lavage cells from patients with sarcoidosis. The effects of serum amyloid A on regulating helper T cell type 1 (Th1) granulomatous inflammation were determined in experimental models of sarcoidosis, using Mycobacterium tuberculosis catalase-peroxidase. We found that the intensity of expression and distribution of serum amyloid A within sarcoidosis granulomas was unlike that in many other granulomatous diseases. Serum amyloid A localized to macrophages and giant cells within sarcoidosis granulomas but correlated with CD3(+) lymphocytes, linking expression to local Th1 responses. Serum amyloid A activated NF-kappaB in Toll-like receptor-2-expressing human cell lines; regulated experimental Th1-mediated granulomatous inflammation through IFN-gamma, tumor necrosis factor, IL-10, and Toll-like receptor-2; and stimulated production of tumor necrosis factor, IL-10, and IL-18 in lung cells from patients with sarcoidosis, effects inhibited by blocking Toll-like receptor-2. Serum amyloid A is a constituent and innate regulator of granulomatous inflammation in sarcoidosis through Toll-like receptor-2, providing a mechanism for chronic disease and new therapeutic targets.

Monocyte heterogeneity in angiotensin-converting enzyme induction mediated by autologous T lymphocytes.

The ability of monocyte subpopulations to be induced selectively by T lymphocytes to synthesize enhanced levels of angiotensin-converting enzyme (ACE) was examined using an in vitro model employing normal peripheral blood monocytes and T lymphocytes. Separation of monocytes into subpopulations on the basis of buoyant density indicated no difference in the ability of the resulting monocyte subpopulations to produce basal levels of ACE when cultured in the absence of T lymphocytes. However, the subpopulations differed significantly in their ability to synthesize enhanced levels of ACE in response to the presence of autologous T lymphocytes; low-density monocytes were induced by T lymphocytes to synthesize three-fold more ACE than were high-density monocytes. Surface antigen labelling using MoAbs demonstrated that the low-density monocyte subpopulations also had a significantly higher percentage of Leu-M2+ monocytes compared with the high-density monocyte subpopulations. When monocytes were separated on the basis of the presence of the Leu-M2 antigen using an immune rosetting technique, T lymphocytes were able to induce significantly elevated levels of ACE in the Leu-M2+ enriched monocyte subpopulation but were unable to induce ACE beyond basal levels in the Leu-M2(+)-depleted monocyte subpopulation. These results demonstrate that monocytes are heterogeneous with respect to their ability to be induced by T lymphocytes to synthesize ACE. This raises the possibility that selective accumulation of a monocyte subpopulation in the granulomatous inflammation of sarcoidosis may be one of the factors required for elevated ACE synthesis in the resulting granuloma epithelioid cells.

Mycobacterial catalase-peroxidase is a tissue antigen and target of the adaptive immune response in systemic sarcoidosis.

Sarcoidosis is a disease of unknown etiology characterized by noncaseating epithelioid granulomas, oligoclonal CD4+ T cell infiltrates, and immune complex formation. To identify pathogenic antigens relevant to immune-mediated granulomatous inflammation in sarcoidosis, we used a limited proteomics approach to detect tissue antigens that were poorly soluble in neutral detergent and resistant to protease digestion, consistent with the known biochemical properties of granuloma-inducing sarcoidosis tissue extracts. Tissue antigens with these characteristics were detected with immunoglobulin (Ig)G or F(ab′)2 fragments from the sera of sarcoidosis patients in 9 of 12 (75%) sarcoidosis tissues (150–160, 80, or 60–64 kD) but only 3 of 22 (14%) control tissues (all 62–64 kD; P = 0.0006). Matrix-assisted laser desorption/ionization time of flight mass spectrometry identified Mycobacterium tuberculosis catalase–peroxidase (mKatG) as one of these tissue antigens. Protein immunoblotting using anti-mKatG monoclonal antibodies independently confirmed the presence of mKatG in 5 of 9 (55%) sarcoidosis tissues but in none of 14 control tissues (P = 0.0037). IgG antibodies to recombinant mKatG were detected in the sera of 12 of 25 (48%) sarcoidosis patients compared with 0 of 11 (0%) purified protein derivative (PPD)− (P = 0.0059) and 4 of 10 (40%) PPD+ (P = 0.7233) control subjects, suggesting that remnant mycobacterial catalase–peroxidase is one target of the adaptive immune response driving granulomatous inflammation in sarcoidosis.

Treatment of sarcoidosis – from a basic science point of view

Progress in our understanding of the scientific basis of granulomatous inflammation in sarcoidosis provides a framework for enlightened treatment decisions. Current evidence supports the concept that the pathogenesis of sarcoidosis involves a highly polarized T-helper 1 (Th1) immune response to pathogenic tissue antigens. Conventional treatment is focused on attenuating granuloma formation with antimalarial drugs that inhibit antigen presentation or with nonspecific anti-inflammatory agents such as glucocorticosteroids, methotrexate, or azathioprine. Anti-tumour necrosis factor (TNF)-alpha agents such as pentoxifylline, thalidomide, etanercept and remicade, have recently shown some successes in sarcoidosis. Designing future therapies depends on improved knowledge of the critical immunological processes operative in different stages of disease.

In situ localization of Propionibacterium acnes DNA in lymph nodes from sarcoidosis patients by signal amplification with catalysed reporter deposition.

Sarcoidosis is a systemic granulomatous disease of unknown aetiology. Many genomes of Propionibacterium acnes and P. granulosum have been detected in lymph nodes from patients with sarcoidosis. In situ localization of propionibacterial genomes in sarcoid lymph nodes may help to establish an aetiological link between sarcoidosis and these indigenous bacteria. Formalin-fixed and paraffin-embedded biopsy samples of lymph nodes from nine patients with sarcoidosis, nine patients with tuberculosis, and nine patients with non-specific lymphadenitis as controls were examined by quantitative real-time PCR (QPCR) for P. acnes and by in situ hybridization (ISH) that used catalysed reporter deposition (CARD) for signal amplification with digoxigenin-labelled oligonucleotide probes that complemented 16S rRNA of P. acnes. The signals per 250 micro m(2) of tissue sections were counted from inside and outside the granulomas of sarcoidosis and tuberculosis and from control lymph nodes. The number of genomes by QPCR was examined for correlation with the mean signal count by ISH with CARD. In sarcoid samples, one or several signals were detected in the cytoplasm of some epithelioid cells in granulomas and of many mononuclear cells around granulomas. The mean signal counts were higher (p < 0.001) in granulomatous areas than in other areas of sarcoid lymph nodes. Even in their non-granulomatous areas, counts were higher than in granulomatous areas (p = 0.0023) and non-granulomatous areas (p < 0.001) of tuberculous lymph nodes and control lymph nodes (p = 0.0071). Correlation between the results by QPCR and ISH with CARD was significant (r = 0.86, p < 0.001). The accumulation of P. acnes genomes in and around sarcoid granulomas suggests that this indigenous bacterium may be related to the cause of granulomatous inflammation in sarcoidosis.

Expression of C-C chemokines in bronchoalveolar lavage cells from patients with granulomatous lung diseases.

To determine the role of C-C chemokines in the pathogenesis of granulomatous lung diseases, we studied the mRNA levels of C-C chemokines, regulated on activation normal T expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and monocyte chemoattractant protein (MCP)-1 in bronchoalveolar lavage (BAL) cells obtained from patients with sarcoidosis (n = 17), hypersensitivity pneumonitis (HP) (n = 4), and cryptogenic fibrosing alveolitis (CFA) (n = 10) using the reverse transcription-polymerase chain reaction (RT-PCR) technique. The mRNA levels of RANTES, MIP-1alpha, and MIP-1beta in BAL cells were significantly correlated with the lavaged lymphocyte proportion, and a significant inverse correlation was observed between the mRNA level of MIP-1beta and the CD4/CD8 ratio of lavaged lymphocytes. Among the three diseases, the mRNA levels of RANTES and MIP-1alpha were significantly higher in the patients with sarcoidosis or HP compared with those in the patients with CFA. The level of MIP-1beta mRNA was significantly higher in the HP patients compared with that in the patients with sarcoidosis or CFA. No significant differences were observed in the level of MCP-1 mRNA among the three diseases. Thus, RANTES and MIP-1alpha were suggested to be important in the pathogenesis of granulomatous inflammation in sarcoidosis and HP. MIP-1beta might play an important role in the pathogenesis of HP, mediating the recruitment of lymphocytes specific to HP.

Apoptosis in the course of granulomatous inflammation in pulmonary sarcoidosis.

Sarcoidosis is a chronic inflammatory disease of unknown aetiology characterized by the formation of non-necrotizing granulomas. The course of disease is usually self-limiting with the spontaneous resolution of granuloma. In the immune system, Fas antigen (Fas) and Fas ligand (FasL) are involved in the down regulation of immune reactions by inducing apoptosis. Therefore, it was hypothesized that the Fas/FasL pathway and apoptosis may be associated with the course of granulomatous inflammation in sarcoidosis. Terminal deoxynucleotidyl transferase-mediated biotin nick end-labelling (TUNEL) was performed to assess deoxyribonucleic acid strand breakages as a characteristic of apoptosis. Immunohistochemistry was also performed to detect Fas and FasL protein, and reverse transcriptase polymerase chain reaction (RT-PCR) and RT in situ PCR to detect FasL messenger ribonucleic acid (mRNA). Positive signals for TUNEL were detected in epithelioid histiocytes and lymphocytes within granulomas and in bronchoalveolar lavage (BAL) lymphocytes from patients with sarcoidosis. Positive signals for Fas were also detected in these cells. FasL mRNA was expressed in BAL lymphocytes from 15 of 20 patients with sarcoidosis, but from only one of 10 patients with normal lung parenchyma. FasL protein was expressed in lymphocytes surrounding and within the granuloma. There was a significant correlation between the result of TUNEL and clinical course in patients with sarcoidosis. Apoptosis in epithelioid histiocytes and inflammatory cells seems to participate in the course of granulomatous inflammation. Further studies are needed to determine the role of Fas, FasL and other regulatory factors in apoptosis in the granulomatous inflammation in pulmonary sarcoidosis.

Cytokine-induced airway epithelial ICAM-1 upregulation: quantification by high-resolution scanning and transmission electron microscopy

Sarcoidosis is a chronic inflammatory disease of unknown aetiology characterized by the formation of non-necrotizing granulomas. The course of disease is usually self-limiting with the spontaneous resolution of granuloma. In the immune system, Fas antigen (Fas) and Fas ligand (FasL) are involved in the down regulation of immune reactions by inducing apoptosis. Therefore, it was hypothesized that the Fas/FasL pathway and apoptosis may be associated with the course of granulomatous inflammation in sarcoidosis. Terminal deoxynucleotidyl transferase-mediated biotin nick end-labelling (TUNEL) was performed to assess deoxyribonucleic acid strand breakages as a characteristic of apoptosis. Immunohistochemistry was also performed to detect Fas and FasL protein, and reverse transcriptase polymerase chain reaction (RT-PCR) and RT in situ PCR to detect FasL messenger ribonucleic acid (mRNA). Positive signals for TUNEL were detected in epithelioid histiocytes and lymphocytes within granulomas and in bronchoalveolar lavage (BAL) lymphocytes from patients with sarcoidosis. Positive signals for Fas were also detected in these cells. FasL mRNA was expressed in BAL lymphocytes from 15 of 20 patients with sarcoidosis, but from only one of 10 patients with normal lung parenchyma. FasL protein was expressed in lymphocytes surrounding and within the granuloma. There was a significant correlation between the result of TUNEL and clinical course in patients with sarcoidosis. Apoptosis in epithelioid histiocytes and inflammatory cells seems to participate in the course of granulomatous inflammation. Further studies are needed to determine the role of Fas, FasL and other regulatory factors in apoptosis in the granulomatous inflammation in pulmonary sarcoidosis.

Phenotypic analysis of lymphocytes and monocytes/macrophages in peripheral blood and bronchoalveolar lavage fluid from patients with pulmonary sarcoidosis

BACKGROUNDThe granulomatous inflammation in sarcoidosis is driven by the interplay between T cells and macrophages. To gain a better understanding of this process the expression by these cells of cell...