IL-12 and IL-18 are increased and stimulate IFN-gamma production in sarcoid lungs

Jiawei Yanghe Decoction alleviates pulmonary sarcoidosis by upregulating NR1D1/2 and suppressing Th17 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Yanghe Decoction (JWYHD) is a modified version traditional Chinese medicine formula Yanghe Decoction which has been used to treat various autoimmune diseases. However, the effect of JWYHD on pulmonary sarcoidosis remains unclear.

AIM OF THE STUDY

This study aimed to determine the therapeutic efficacy and potential mechanism of action of JWYHD in pulmonary sarcoidosis.

MATERIALS AND METHODS

A murine model of sarcoidosis was established by intravenous injection of inactivated Propionibacterium acnes and mature dendritic cells to assess the efficacy of JWYHD. Lung tissue mRNA sequencing was conducted to identify the targets of JWYHD's action. Molecular docking verified of the interaction between identified compounds and key targets.

RESULTS

JWYHD treatment alleviated the formation of granulomas in the lung tissue of sarcoidosis model mice. JWYHD significantly attenuated the pulmonary accumulation of macrophages and CD4+T lymphocytes in sarcoidosis mice, and effectively suppressed the proportion of Th17 cells and the levels of IL-17A and TNF-α in BALF, which are pivotal in the pathogenesis of granuloma formation and progression. The therapeutic efficacy of JWYHD was found to be equivalent to that of prednisone. RNA-seq revealed that JWYHD upregulated Nr1d1/2 expression in the lung tissue. Nr1d1/2 is highly expressed in Th17 cells and regulates their differentiation. The NR1D1/2 agonist SR9009 could inhibit Th17 cell proportion and reduce the formation of pulmonary granuloma, exhibiting effects similar to those of JWYHD. Molecular docking result showed that Cyclocephaloside II, Epimedin B, Glycyrrhetic acid, Glycyrrhizic acid, Uralsaponin B, and Uralsaponin U may be key compounds in JWYHD for the treatment of pulmonary sarcoidosis, which had a strong binding ability for NR1D1/2.

CONCLUSIONS

JWYHD might exert a therapeutic benefit in pulmonary sarcoidosis through upregulating NR1D1/2 and suppressing Th17 cells. NR1D1/2 might serve as a therapeutic target for the treatment of pulmonary sarcoidosis.

Pulmonary sarcoidosis: A comprehensive review: Past to present

Sarcoidosis is a sterile non-necrotizing granulomatous disease without known causes that can involve multiple organs with a predilection for the lung and thoracic lymph nodes. Worldwide it is estimated to affect 2-160/100,000 people and has a mortality rate over 5 years of approximately 7%. For sarcoidosis patients, the cause of death is due to sarcoid in 60% of the cases, of which up to 80% are from advanced cardiopulmonary failure (pulmonary hypertension and respiratory microbial infections) in all races except in Japan were greater than 70% of the sarcoidosis deaths are due to cardiac sarcoidosis. Scadding stages for pulmonary sarcoidosis associates with clinical outcomes. Stages I and II have radiographic remission in approximately 30%-80% of cases. Stage III only has a 10%-40% chance of resolution, while stage IV has no change of resolution. Up to 40% of pulmonary sarcoidosis patients progress to stage IV disease with lung parenchyma fibroplasia, bronchiectasis with hilar retraction and fibrocystic disease. These patients are at highest risk for the development of precapillary pulmonary hypertension, which may occur in up to 70% of these patients. Sarcoid patients with pre-capillary pulmonary hypertension can respond to targeted pulmonary arterial hypertension medications. Stage IV fibrocytic sarcoidosis with significant pulmonary physiologic impairment, >20% fibrosis on HRCT or pre-capillary pulmonary hypertension have the highest risk of mortality, which can be >40% at 5-years. First line treatment for patients who are symptomatic (cough and dyspnea) with parenchymal infiltrates and abnormal pulmonary function testing (PFT) is oral glucocorticoids, such as prednisone with a typical starting dose of 20-40 mg daily for 2 weeks to 2 months. Prednisone can be tapered over 6-18 months if symptoms, spirometry, PFTs, and radiographs improve. Prolonged prednisone may be required to stabilize disease. Patients requiring prolonged prednisone ≥10 mg/day or those with adverse effects due to glucocorticoids may be prescribed second and third line treatements. Second and third line treatments include immunosuppressive agents (e.g., methotrexate and azathioprine) and anti-tumor necrosis factor (TNF) medication; respectively. Effective treatments for advanced fibrocystic pulmonary disease are being explored. Despite different treatments, relapse rates range from 13% to 75% depending on the stage of sarcoid, number of organs involved, socioeconomic status, and geography. CONCLUSION: The mortality rate for sarcoidosis over a 5 year follow up is approximately 7%. Unfortunately, 10%-40% of patients with sarcoidosis develop progressive pulmonary disease, and >60% of deaths resulting from sarcoidosis are due to advance cardiopulmonary disease. Oral glucocorticoids are the first line treatment, while methotrexate and azathioprine are considered second and anti-TNF agents are third line treatments that are used solely or as glucocorticoid sparing agents for symptomatic extrapulmonary or pulmonary sarcoidosis with infiltrates on chest radiographs and abnormal PFT. Relapse rates have ranged from 13% to 75% depending on the population studied.

Developmental drugs for sarcoidosis

Sarcoidosis is a multi-organ granulomatous inflammatory disease of unknown etiology. Over 50% of patients will require treatment at some point in their disease and 10%-30% will develop a chronic progressive disease with pulmonary fibrosis leading to significant morbidity and mortality. Recently published guidelines recommend immunosuppressive therapy for sarcoidosis patients at risk of increased disease-related morbidity and mortality, and in whom disease has negatively impacted quality of life. Prednisone the currently recommended first line therapy is associated with significant toxicity however none of the other guideline recommended steroid sparing therapy is approved by regulatory agencies for use in sarcoidosis, and data in support of their use is weak. For patients with severe refractory disease requiring prolonged therapy, treatment options are limited. The need for expanding treatment options in sarcoidosis has been emphasized. Well conducted large, randomized trials evaluating currently available therapeutic options as well as novel pathways for targeting disease are necessary to better guide treatment decisions. These trials will not be without significant challenges. Sarcoidosis is a rare disease with heterogenous presentation and variable progression and clinical outcome. There are no universally agreed upon biomarkers of disease activity and measurement of outcomes is confounded by the need to balance patient centric measures and objective measures of disease activity. Our paper provides an update on developmental drugs in sarcoidosis and outlines several novel pathways that may be targeted for future drug development. Currently available trials are highlighted and ongoing challenges to drug development and clinical trial design are briefly discussed.

The immunopathogenesis of sarcoidosis

Sarcoidosis is a granulomatous multiorgan disease, thought to result from exposure to yet unidentified antigens in genetically susceptible individuals. The exaggerated inflammatory response that leads to granuloma formation is highly complex and involves the innate and adaptive immune system. Consecutive immunological studies using advanced technology have increased our understanding of aberrantly activated immune cells, mediators and pathways that influence the formation, maintenance and resolution of granulomas. Over the years, it has become increasingly clear that disease immunopathogenesis can only be understood if the clinical heterogeneity of sarcoidosis is taken into consideration, along with the distribution of immune cells in peripheral blood and involved organs. Most studies offer an immunological snapshot during disease course, while the cellular composition of both the circulation and tissue microenvironment may change over time. Despite these challenges, novel insights on the role of the immune system are continuously published, thus bringing the field forward. This review highlights current knowledge on the innate and adaptive immune responses involved in sarcoidosis pathogenesis, as well as the pathways involved in non-resolving disease and fibrosis development. Additionally, we describe proposed immunological mechanisms responsible for drug-induced sarcoid like reactions. Although many aspects of disease immunopathogenesis remain to be unraveled, the identification of crucial immune reactions in sarcoidosis may help identify new treatment targets. We therefore also discuss potential therapies and future strategies based on the latest immunological findings.

Targeting cytokine networks in neuroinflammatory diseases

In neuroinflammatory diseases, systemic (blood-borne) leukocytes invade the central nervous system (CNS) and lead to tissue damage. A causal relationship between neuroinflammatory diseases and dysregulated cytokine networks is well established across several preclinical models. Cytokine dysregulation is also observed as an inadvertent effect of cancer immunotherapy, where it often leads to neuroinflammation. Neuroinflammatory diseases can be separated into those in which a pathogen is at the centre of the immune response and those of largely unknown aetiology. Here, we discuss the pathophysiology, cytokine networks and therapeutic landscape of 'sterile' neuroinflammatory diseases such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), neurosarcoidosis and immune effector cell-associated neurotoxicity syndrome (ICANS) triggered by cancer immunotherapy. Despite successes in targeting cytokine networks in preclinical models of neuroinflammation, the clinical translation of targeting cytokines and their receptors has shown mixed and often paradoxical responses.

Anti-inflammatory Therapy for Sarcoidosis

Over 50% of patients with sarcoidosis will require anti-inflammatory therapy at some point in their disease course. Indications for therapy are to improve health-related quality of life, prevent or arrest organ dysfunction (or organ failure) or avoid death. Recently published treatment guidelines recommended a stepwise approach to therapy however there are some patients for whom up front combination or more intense therapy maybe reasonable. The last decade has seen an explosion of studies and trials evaluating novel therapeutic agents and treatment strategies. Currently available anti-inflammatory therapies and several novel therapies are discussed here.

Systemic and cerebrospinal fluid biomarkers for tuberculous meningitis identification and treatment monitoring

IMPORTANCE

Tuberculous meningitis is a life-threatening infection with high mortality and disability rates. Current diagnostic methods using cerebrospinal fluid (CSF) samples have limited sensitivity and lack predictive biomarkers for evaluating prognosis. This study's findings reveal excessive activation of the immune response during tuberculous meningitis (TBM) infection. Notably, a strong negative correlation was observed between CSF levels of monokine induced by interferon-γ (MIG) and the CSF/blood glucose ratio in TBM patients. MIG also exhibited the highest area under the curve with high sensitivity and specificity. This study suggests that MIG may serve as a novel biomarker for differentiating TBM infection in CSF or serum, potentially leading to improved diagnostic accuracy and better patient outcomes.

Increased circulating interleukin-23 level in patients with sarcoidosis

BACKGROUND

Sarcoidosis is a Th1-mediated chronic inflammatory disease characterized by non-caseating granulomas. Its pathogenesis is not yet clear, but the possible role of various proinflammatory cytokines is being discussed.

AIM

This study aims to determine serum cytokine (IL-6, IL-12, IL-17, and IL-23) levels in patients with sarcoidosis, and to determine a possible correlation with clinical and laboratory findings of the disease.

MATERIAL AND METHOD

Forty-four biopsy-proven sarcoidosis patients followed up at a single centre and 41 healthy volunteers were included in the study. Demographic, clinical, laboratory, and radiological data of all patients were recorded. Serum samples from the patients and the control group were taken and IL-6, IL-12, IL-17, IL-23 were measured by ELISA method.

RESULTS

Of the 44 sarcoidosis patients, 13(29.5%) were male and 31(70.5%) were female. Average patient age was 47.4 years, mean disease duration was 3.2 years. Twenty-one (47.7%) patients had erythema nodosum, three (6.8%) had uveitis, 40(90.9%) had arthralgia, 23(52.3%) had ankle arthritis, 15(34.1%) had enthesitis. Laboratory evaluation showed increased serum ACE levels in 24(54.5%) patients, increased serum calcium levels in 11 (25%) patients, increased serum D3 levels in 5(11.4%) patients, increased ESR and CRP levels in 22(50%) and 23(52.3%) patients, respectively. Compared with the control group higher serum IL-23 levels were found in the patients with sarcoidosis (p=.01). Serum IL-23 was associated with ankle arthritis (p=.02). Serum IL-6, IL-12, and IL-17 levels were similar in the sarcoidosis patients and the control group (p=.128, p=.212, p=.521 respectively).

CONCLUSION

In our study, we found increased serum IL-23 in patients with sarcoidosis, while serum IL-6, IL-12, and IL-17 were detected as normal. Although our results are somewhat contradictory to other studies in the literature, the question should still be whether sarcoidosis is a Th1/Th17 disease. Multicentre studies are needed in this regard.

Molecularly Targeted Therapies for Inflammatory Cutaneous Granulomatous Disorders: A Review of the Evidence and Implications for Understanding Disease Pathogenesis

Inflammatory cutaneous granulomatous diseases, including granuloma annulare, cutaneous sarcoidosis, and necrobiosis lipoidica, are distinct diseases unified by the hallmark of macrophage accumulation and activation in the skin. There are currently no Food and Drug Administration-approved therapies for these conditions except prednisone and repository corticotropin injection for pulmonary sarcoidosis. Treatment of these diseases has generally been guided by low-quality evidence and may involve broadly immunomodulatory medications. Development of new treatments has in part been limited by an incomplete understanding of disease pathogenesis. Recently, there has been substantial progress in better understanding the molecular pathogenesis of these disorders, opening the door for therapeutic innovation. Likewise, reported outcomes of treatment with immunologically targeted therapies may offer insights into disease pathogenesis. In this systematic review, we summarize progress in deciphering the pathomechanisms of these disorders and discuss this in the context of emerging evidence on the use of molecularly targeted therapies in treatment of these diseases.

Imbalanced distribution of regulatory T cells and Th17.1 cells in the peripheral blood and BALF of sarcoidosis patients: relationship to disease activity and the fibrotic radiographic phenotype

Rationale

Sarcoidosis is a granulomatous interstitial lung disease involving a complex interplay among different cluster of differentiation 4 (CD4⁺) thymus cell (T-cell) subsets. Originally described as a type 1 T-helper (Th1) inflammatory disease, recent evidence suggests that both effector and regulatory T-cell subgroups play a critical role in sarcoidosis, but this remains controversial.

Objectives

We aimed to investigate the distribution of CD4⁺ T-cell subpopulations in sarcoidosis patients and its potential associations with clinical disease activity and a radiographic fibrotic phenotype.

Methods

We measured the frequencies of regulatory T cells (Tregs), Th1, Th17, and Th17.1 cells in the peripheral blood and/or bronchoalveolar lavage fluid (BALF) of 62 sarcoidosis patients, 66 idiopathic pulmonary fibrosis (IPF) patients, and 41 healthy volunteers using flow cytometry. We also measured the changes in these T-cell subpopulations in the blood at the follow-up visits of 11 sarcoidosis patients.

Measurements and results

An increased percentage of Tregs was observed in the peripheral blood of sarcoidosis patients, with a positive association to disease activity and a fibrotic radiographic phenotype. We found a higher frequency of Tregs, a lower proportion of Th17.1 cells, and a lower ratio of Th17.1 cells to total Tregs in the peripheral blood of both active and fibrotic sarcoidosis patients, compared with IPF patients or healthy donors. In contrast, a lower frequency of Tregs and a higher proportion of Th17.1 cells was found in the BALF of sarcoidosis patients than in that of IPF patients. There was an imbalance of Tregs and Th17.1 cells between the peripheral blood and BALF in sarcoidosis patients. Following immunoregulatory therapy, the proportion of circulating Tregs in sarcoidosis patients decreased.

Conclusion

A higher proportion of Tregs in the peripheral blood of sarcoidosis patients was related to disease activity, fibrotic phenotype, and the need for immunoregulatory therapy. The imbalanced distribution of Tregs and Th17.1 cells in patients' peripheral blood and BALF suggests that the lung microenvironment has an effect on the immunological pathogenesis of sarcoidosis. Therefore, further studies on the functional analysis of Tregs and Th17.1 cells in sarcoidosis patients are warranted.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

Sarcoidosis is a systemic granulomatous inflammatory disease of unknown etiology. It affects the lungs in over 90% of patients yet extra-pulmonary and multi-organ involvement is common. Spontaneous remission of disease occurs commonly, nonetheless, over 50% of patients will require treatment and up to 30% of patients will develop a chronic progressive non-remitting disease with marked pulmonary fibrosis leading to significant morbidity and death. Guidelines outlining an immunosuppressive treatment approach to sarcoidosis were recently published, however, the strength of evidence behind many of the guideline recommended drugs is weak. None of the drugs currently used for the treatment of sarcoidosis have been rigorously studied and prescription of these drugs is often based on off-label” indications informed by experience with other diseases. Indeed, only two medications [prednisone and repository corticotropin (RCI) injection] currently used in the treatment of sarcoidosis are approved by the United States Food and Drug Administration. This situation results in significant reimbursement challenges especially for the more advanced (and often more effective) drugs that are favored for severe and refractory forms of disease causing an over-reliance on corticosteroids known to be associated with significant dose and duration dependent toxicities. This past decade has seen a renewed interest in developing new drugs and exploring novel therapeutic pathways for the treatment of sarcoidosis. Several of these trials are active randomized controlled trials (RCTs) designed to recruit relatively large numbers of patients with a goal to determine the safety, efficacy, and tolerability of these new molecules and therapeutic approaches. While it is an exciting time, it is also necessary to exercise caution. Resources including research dollars and most importantly, patient populations available for trials are limited and thus necessitate that several of the challenges facing drug trials and drug development in sarcoidosis are addressed. This will ensure that currently available resources are judiciously utilized. Our paper reviews the ongoing and anticipated drug trials in sarcoidosis and addresses the challenges facing these and future trials. We also review several recently completed trials and draw lessons that should be applied in future.

Histology of Cardiac Sarcoidosis with Novel Considerations Arranged upon a Pathologic Basis

Sarcoidosis is a rare disease of isolated or diffuse granulomatous inflammation. Although any organs can be affected by sarcoidosis, cardiac sarcoidosis is a fatal disorder, and it is crucial to accurately diagnose it to prevent sudden death due to dysrhythmia. Although endomyocardial biopsy is invasive and has limited sensitivity for identifying granulomas, it is the only modality that yields a definitive diagnosis of cardiac sarcoidosis. It is imperative to develop novel pathological approaches for the precise diagnosis of cardiac sarcoidosis. Here, we aimed to discuss commonly used diagnostic criteria for cardiac sarcoidosis and to summarize useful and novel histopathologic criteria of cardiac sarcoidosis. While classical histologic observations including noncaseating granulomas and multinucleated giant cells (typically Langhans type) are the most important findings, others such as microgranulomas, CD68⁺ CD163^- pro-inflammatory (M1) macrophage accumulation, CD4/CD8 T-cell ratio, Cutibacterium acnes components, lymphangiogenesis, confluent fibrosis, and fatty infiltration may help to improve the sensitivity of endomyocardial biopsy for detecting cardiac sarcoidosis. These novel histologic findings are based on the pathology of cardiac sarcoidosis. We also discussed the principal histologic differential diagnoses of cardiac sarcoidosis, such as tuberculosis myocarditis, fungal myocarditis, giant cell myocarditis, and dilated cardiomyopathy.

Potential therapeutic targets to prevent organ damage in chronic pulmonary sarcoidosis

INTRODUCTION

Sarcoidosis is a granulomatous inflammatory disease with high chances of reduced quality of life, irreversible organ damage, and reduced life expectancy when vital organs are involved. Any organ system can be affected, and the lungs are most often affected. There is no preventive strategy as the exact etiology is unknown, and complex immunogenetic and environmental factors determine disease susceptibility and phenotype. Present-day treatment options originated from clinical practice and are effective in many patients. However, a substantial percentage of patients suffer from unacceptable side effects or still develop refractory, threatening pulmonary or extrapulmonary disease.

AREAS COVERED

As non-caseating granulomas, the pathological hallmark of disease, are assigned to divergent activation and regulation of the immune system, targets in relation to the possible triggers of granuloma formation and their sequelae were searched and reviewed.

EXPERT OPINION

:The immunopathogenesis underlying sarcoidosis has been a dynamic field of study. Several recent new insights give way to promising new therapeutic targets, such as certain antigenic triggers (e.g. from Aspergillus nidulans), mTOR, JAK-STAT and PPARγ pathways, the NRP2 receptor and MMP-12, which await further exploration. Clinical and trigger related phenotyping, and molecular endotyping in sarcoidosis will likely hold the key for precision medicine in the future.

Effects of intra-articular inoculation with Mycoplasma bovis on immunological responses in calf joints

Mycoplasma arthritis that caused by Mycoplasma bovis exhibit severe lameness. This disease is difficult to cure with antibiotics, but the detailed pathological mechanisms have not been fully clarified. In this study, we examined the effects of intra-articular inoculation with M. bovis on immunological responses in calf joints. We inoculated three calves each with M. bovis or phosphate buffer saline (control) into the right stifle joint and dissected them at 15 days postinoculation. Mycoplasma bovis-inoculated calves exhibited swelling of the stifle joint, increases in synovial fluid, fibrin deposition, and cartilage thinning. Intracellular M. bovis was detected in synovial tissues analyzed by immunohistochemistry and transmission electron microscopy. Messenger RNA expressions of interleukin (IL)-1β, IL-6, IL-8, IL-12p40, and IL-17A in synovial fluid cells and synovial tissues from M. bovis-inoculated calves were significantly higher than those from control calves. Protein levels of these cytokines in synovial fluid from M. bovis-inoculated calves were markedly higher than those from control calves. Our study clarified that inoculation with M. bovis into the stifle joint induced the production of inflammatory cytokines by synovial fluid cells and synovial tissues, causing a severe inflammatory response in joints. Additionally, M. bovis could invade cells in synovial tissues, which may have aided it in evading antibiotics and host immune surveillance.

The Role of Diverse Immune Cells in Sarcoidosis

Sarcoidosis is a systemic inflammatory disorder of unknown etiology characterized by tissue infiltration with macrophages and lymphocytes and associated non-caseating granuloma formation. The disease primarily affects the lungs. Patients suffering from sarcoidosis show a wide range of clinical symptoms, natural history and disease outcomes. Originally described as a Th1-driven disease, sarcoidosis involves a complex interplay among diverse immune cells. This review highlights recent advances in the pathogenesis of sarcoidosis, with emphasis on the role of different immune cells. Accumulative evidence suggests Th17 cells, IFN-γ-producing Th17 cells or Th17.1 cells, and regulatory T (Treg) cells play a critical role. However, their specific actions, whether protective or pathogenic, remain to be clarified. Macrophages are also involved in granuloma formation, and M2 polarization may be predictive of fibrosis. Previously neglected cells including B cells, dendritic cells (DCs), natural killer (NK) cells and natural killer T (NKT) cells were studied more recently for their contribution to sarcoid granuloma formation. Despite these advances, the pathogenesis remains incompletely understood, indicating an urgent need for further research to reveal the distinct immunological events in this process, with hope to open up new therapeutic avenues and if possible, to develop preventive measures.

Sarcoidosis manifesting during treatment with secukinumab for psoriatic arthritis

Sarcoidosis is a multisystem inflammatory disorder of uncertain aetiology. There are numerous case reports of sarcoidosis occurring during treatment with biological immunotherapies. Here, we describe the case of a 52-year-old woman with psoriatic arthritis who developed multisystem sarcoidosis while being treated with secukinumab (anti-interleukin-17A) therapy which, to our knowledge, is the first such case. We discuss existing literature and hypothesise that IL-17 blockade may precipitate the development of granulomatous disease.

Musculoskeletal sarcoidosis: A single center experience over 15 years

BACKGROUND

Musculoskeletal (MSK) sarcoidosis presents with a variety of clinical phenotypes. Four subtypes of MSK sarcoidosis have been identified to date: Lofgren syndrome, chronic sarcoid arthritis, osseous sarcoidosis, sarcoid myopathy. Each subtype has been reported with varying incidence mainly due to lack of universal classification criteria.

METHODS

We performed a retrospective chart review of patients with MSK sarcoidosis at a single academic center between January 2000 and December 2014. Descriptive statistics were used to describe the proportion of patients with sarcoidosis who had the 4 MSK syndromes of interest, demographic characteristics and therapeutic agents used.

RESULTS

A cohort of 58 patients with MSK manifestations were identified among 1016 patients with sarcoidosis. Frequency of subtypes include: Lofgren syndrome 46.6%, osseous sarcoidosis 25.9%, chronic sarcoid arthritis 24.1% and sarcoid myopathy 6.9%. The cohort was predominantly female (43/58 patients, 74%) and Caucasian (48/58 patients, 82.8%). Mean age was 47.2 years. One patient had overlap of osseous sarcoidosis and chronic sarcoid arthritis, another patient initially had Lofgren syndrome and later developed chronic sarcoid arthritis. Sarcoid myopathy patients presented with myalgia more often than muscle weakness.

CONCLUSION

We identified a large cohort of MSK sarcoidosis and determined the prevalence of all 4 subtypes. In patients who do develop MSK manifestations of sarcoidosis, they are commonly a part of the initial presentation of sarcoidosis. There is an unmet need to establish standardized classification criteria for the 4 MSK sarcoidosis syndromes.

Biologic and advanced immunomodulating therapeutic options for sarcoidosis: a clinical update

Introduction: Sarcoidosis is a multi-organ disease with a wide range of clinical manifestations and outcomes. A quarter of sarcoidosis patients require long-term treatment for chronic disease. In this group, corticosteroids and cytotoxic agents be insufficient to control diseaseAreas covered: Several biologic agents have been studied for treatment of chronic pulmonary and extra-pulmonary disease. A review of the available literature was performed searching PubMed and an expert opinion regarding specific therapy was developed.Expert opinion: These agents have the potential of treating patients who have progressive disease. Many of these agents have different mechanisms of action, response rates, and toxicity profiles.

Emerging Molecular Targets for the Treatment of Refractory Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown origin that has variable clinical course and can affect nearly any organ. It has a chronic course in about 25% of patients. Corticosteroids (CS) are the cornerstone of therapy but their long-term use is associated with cumulative toxicity. Commonly used CS-sparing agents include methotrexate, cyclophosphamide, azathioprine, and mycophenolate mofetil. Twenty to forty percentage of sarcoidosis patients are refractory to these therapies or develop severe adverse events. Therefore, additional and targeted CS-sparing agents are needed for chronic sarcoidosis. Macrophage activation, interferon response, and formation of the granuloma are mainly mediated by T helper-1 responses. Different pro-inflammatory cytokines such as interleukin (IL)-8, IL-12, IL-6, and tumor necrosis factor-alpha (TNF-α) have been shown to be highly expressed in sarcoidosis-affected tissues. As a result of increased production of these cytokines, Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is constitutively active in sarcoidosis. Several studies of biological agents that target TNF-α have reported their efficacy and appear today as a second line option in refractory sarcoidosis. Some case series report a positive effect of tocilizumab an anti-IL-6 monoclonal antibody in this setting. More recently, JAK inhibition appears as a new promising strategy. This review highlights key advances on the management of chronic refractory sarcoidosis. Novel therapeutic strategies and treatment agents to manage the disease are described.

Sarcoid- like Phenomenon - ustekinumab induced granulomatous reaction mimicking diffuse metastatic disease: a case report and review of the literature

Background

The utilization of monoclonal antibodies has become more widespread over the past decade. However, the development of non-caseating granulomas with the use of monoclonal antibodies, such as ustekinumab, is not widely reported in the literature.

Case presentation

We report a case of a 50-year-old Caucasian male who presented complaining of weight loss and shortness of breath. He was receiving ustekinumab for refractory psoriasis but had no other significant medical comorbidities. On physical examination, reduced breath sounds on the right side were noted. Blood cultures were drawn on presentation and came back negative in 48 hours. A chest computed tomography scan revealed a large right lung mass in addition to right-sided pleural effusion. Therapeutic thoracocentesis was done; fluid cytology and analysis were negative for malignancy, acid-fast bacilli, or fungal infections. A positron emission tomography scan showed multifocal radiotracer uptake including within right lung mass, multiple bones, lymph nodes, liver and spleen. Biopsies showed hyalinized non-necrotizing granulomas. Immunohistochemical stains for AE1/AE3, cytokeratin 7 and 20, and thyroid transcription factor 1, were all negative. He was started on steroid therapy, and ustekinumab was discontinued and the follow-up computed tomography after a few months showed substantial improvement. However, over the course of next 4 months patient developed hepatic dysfunction and recurrent ascites and ultimately underwent transjugular intrahepatic portosystemic shunt placement. Furthermore, he was started on azathioprine and steroids were tapered. He improved clinically and was discharged from our hospital within a week.

Conclusions

This case highlights the need for careful consideration of patient medication history while evaluating the possible differential diagnoses that may contribute to a patient’s presentation.

Moving target: shifting the focus to pulmonary sarcoidosis as an autoimmune spectrum disorder

Despite more than a century of research, the causative agent(s) in sarcoidosis, a heterogeneous granulomatous disorder mainly affecting the lungs, remain(s) elusive. Following identification of genetic factors underlying different clinical phenotypes, increased understanding of CD4⁺ T-cell immunology, which is believed to be central to sarcoid pathogenesis, as well as the role of B-cells and other cells bridging innate and adaptive immunity, contributes to novel insights into the mechanistic pathways influencing disease resolution or chronicity. Hopefully, new perspectives and state-of-the-art technology will help to shed light on the still-elusive enigma of sarcoid aetiology. This perspective article highlights a number of recent advances in the search for antigenic targets in sarcoidosis, as well as the main arguments for sarcoidosis as a spectrum of autoimmune conditions, either as a result of an external (microbial) trigger and/or due to defective control mechanisms regulating the balance between T-cell activation and inhibition.

Augmentation of DTH reaction of mycobacterial antigenic cocktail using synthetic mycobacterial 19-kDa lipoprotein as a TLR-stimulant

The current study proposed that previously characterized individual antigenic proteins could represent potential replacement for conventional purified protein derivative (PPD) in tuberculosis skin testing when used in cocktails triggered by suitable TLR-stimulants that would provide the missing pro-inflammatory stimulus. Three different cocktails of previously selected antigens, including C1 (ESAT-6/CPF-10/MPB-83); C2 (ESAT-6/MPB-64/MPB-83); and C3 (CPF-10/MPB-64/MPB-83), were evaluated in vitro using lymphocytic proliferation and IFN-γ production assays, as well as mRNA and protein expression levels of TNF-α, IL-12p40, and IL-2 as pro-inflammatory molecules. C1 showed the highest significant induction of pro-inflammatory molecules as compared to other cocktails, yet still significantly lower than that induced by conventional PPD. Interestingly, inclusion of the synthetic Mycobacterium tuberculosis 19-kDa lipoprotein (Pam3Cys-SSNKSTTGSGETTTA) as a TLR-stimulant resulted in obvious augmentation of C1-induced pro-inflammatory molecules to levels comparable to that of PPD. In addition, skin testing using sensitized guinea pig model revealed comparable significant reaction to that of conventional PPD. ESAT-6/CPF-10/MPB-83 cocktail is suggested as a potential alternative skin-testing reagent when used in combination with the M. tuberculosis 19-kDa lipoprotein as a TLR-stimulant.

Increased T-helper 17.1 cells in sarcoidosis mediastinal lymph nodes

The lung-draining mediastinal lymph nodes (MLNs) are currently widely used to diagnose sarcoidosis. We previously reported that T-helper (Th) 17.1 cells are responsible for the exaggerated interferon-γ production in sarcoidosis lungs. In this study, we aimed to investigate 1) whether Th17.1 cells are also increased in the MLNs of sarcoidosis patients and 2) whether frequencies of the Th17.1 cells at diagnosis may correlate with disease progression.

MLN cells from treatment-naive pulmonary sarcoidosis patients (n=17) and healthy controls (n=22) and peripheral blood mononuclear cells (n=34) and bronchoalveolar lavage fluid (BALF) (n=36) from sarcoidosis patients were examined for CD4+ T-cell subset proportions using flow cytometry.

Higher proportions of Th17.1 cells were detected in sarcoidosis MLNs than in control MLNs. Higher Th17.1 cell proportions were found in sarcoidosis BALF compared with MLNs and peripheral blood. Furthermore, BALF Th17.1 cell proportions were significantly higher in patients developing chronic disease than in patients undergoing resolution within 2 years of clinical follow-up.

These data suggest that Th17.1 cell proportions in pulmonary sarcoidosis can be evaluated as a diagnostic and/or prognostic marker in clinical practice and could serve as a new therapeutic target.

T-cell immunology in sarcoidosis: Disruption of a delicate balance between helper and regulatory T-cells

PURPOSE OF REVIEW

Although the aetiology of sarcoidosis is not yet completely understood, immunological changes within the T-cell compartment are characteristic for an exaggerated antigen-driven immune response. In this review, we describe the most recent findings on T-cell subset responses and regulation in sarcoidosis. We discuss how future immunological research can advance the field to unravel pathobiological mechanisms of this intriguingly complex disease.

RECENT FINDINGS

Research into the field of T-cell plasticity has recently challenged the long-held T helper type 1 (Th1) paradigm in sarcoidosis and striking parallels with autoimmune disorders and common variable immunodeficiency were recognized. For instance, it was demonstrated that Th17.1-cells rather than Th1-cells are responsible for the exaggerated IFN-γ production in pulmonary sarcoidosis. Furthermore, impaired regulatory T-cell function and alterations within the expression of co-inhibitory receptors that control T-cell responses, such as PD-1, CTLA-4 and BTNL2, raise new questions regarding T-cell regulation in pulmonary sarcoidosis.

SUMMARY

It becomes increasingly clear that Th17(.1)-cells and regulatory T-cells are key players in sarcoidosis T-cell immunology. New findings on plasticity and co-inhibitory receptor expression by these subsets help build a more comprehensive model for T-cell regulation in sarcoidosis and will finally shed light on the potential of new treatment modalities.

Functional Toll-Like Receptor 9 Expression and CXCR3 Ligand Release in Pulmonary Sarcoidosis

Sarcoidosis is a granulomatous disease characterized by a T-helper type 1 (Th1) cell-dominated alveolitis. As a role of bacteria in the pathogenesis of sarcoidosis has been discussed, Toll-like receptors (TLRs) may be involved in the initiation of a first immune reaction. We analyzed expression and functional relevance of several TLRs in bronchoalveolar lavage (BAL) cells from patients with pulmonary sarcoidosis. In parallel, we determined the release of C-X-C motif chemokine 9 (CXCL9), CXCL10, and CXCL11 by BAL cells from patients with pulmonary sarcoidosis. Nucleotide-binding oligomerization domain-containing protein (NOD) 1 and 2, TLR2, TLR6, and TLR9 expression by BAL cells was analyzed by real-time RT-PCR and cell surface expression by flow cytometry. Chemokine release was measured in BAL cell culture supernatants by ELISA. We found increased TLR9 mRNA expression in patients with sarcoidosis with chest X-ray type I and II and TLR9 protein expression in BAL cells from patients with chest X-ray type II and III. Stimulation with CpG nucleotides increased CXCL10 release by BAL cells from patients with sarcoidosis type II significantly compared with control subjects or other patients with sarcoidosis. In contrast, no increase in TNF, IL-12p40, or CXCL8 was detected. Spontaneous release of CXCL10, but not CXCL9 or CXCL11, by cultured BAL cells was also highest in cells from patients with chest X-ray type II. We found a significant association between TLR9 expression and CD4⁺ lymphocytes in BAL. Our data demonstrate that TLR9 ligands may contribute to the immunopathogenesis of sarcoidosis via induction of CXCL10 release in the alveolar macrophages.

IFN-γ-Producing T-Helper 17.1 Cells Are Increased in Sarcoidosis and Are More Prevalent than T-Helper Type 1 Cells

RATIONALE

Pulmonary sarcoidosis is classically defined by T-helper (Th) cell type 1 inflammation (e.g., IFN-γ production by CD4(+) effector T cells). Recently, IL-17A-secreting cells have been found in lung lavage, invoking Th17 immunity in sarcoidosis. Studies also identified IL-17A-secreting cells that expressed IFN-γ, but their abundance as a percentage of total CD4(+) cells was either low or undetermined.

OBJECTIVES

Based on evidence that Th17 cells can be polarized to Th17.1 cells to produce only IFN-γ, our goal was to determine whether Th17.1 cells are a prominent source of IFN-γ in sarcoidosis.

METHODS

We developed a single-cell approach to define and isolate major Th-cell subsets using combinations of chemokine receptors and fluorescence-activated cell sorting. We subsequently confirmed the accuracy of subset enrichment by measuring cytokine production.

MEASUREMENTS AND MAIN RESULTS

Discrimination between Th17 and Th17.1 cells revealed very high percentages of Th17.1 cells in lung lavage in sarcoidosis compared with controls in two separate cohorts. No differences in Th17 or Th1 lavage cells were found compared with controls. Lung lavage Th17.1-cell percentages were also higher than Th1-cell percentages, and approximately 60% of Th17.1-enriched cells produced only IFN-γ.

CONCLUSIONS

Combined use of surface markers and functional assays to study CD4(+) T cells in sarcoidosis revealed a marked expansion of Th17.1 cells that only produce IFN-γ. These results suggest that Th17.1 cells could be misclassified as Th1 cells and may be the predominant producer of IFN-γ in pulmonary sarcoidosis, challenging the Th1 paradigm of pathogenesis.

Bone marrow sarcoidosis associated with long-term interferon-β treatment for multiple sclerosis

Sarcoidosis is a diagnosis that should be considered in patients receiving interferon therapy, who present with anemia and multiorgan dysfunction regardless of the duration of their treatment. When sarcoidosis is suspected, bone marrow biopsy should be considered especially for cases predominant by extrapulmonary features.

Enhanced LPS-induced activation of IL-27 signalling in sarcoidosis

RATIONALE

Granulomas in sarcoidosis have recently been described as containing Interleukin (IL)-27, one of the members of the IL-12 family of cytokines, which also includes IL-35. Levels of these cytokines and the IL-27 receptor subunits were hypothesised to differ between patients with sarcoidosis compared to healthy controls in peripheral blood.

METHODS

Using a cross-sectional study design, plasma and peripheral blood mononuclear cells (PBMC) were collected from patients and control subjects. Protein and mRNA (in PBMC) levels for IL-27 and IL-35 (IL27, EBI3, IL12A subunits) as well as IL-27 receptor (IL6ST and IL27RA subunits) were assessed spontaneously and following direct (LPS) and indirect (anti-CD3/28 activation beads) macrophage stimulation using RT- PCR, ELISA and flow cytometry.

RESULTS

Following stimulation with LPS, PBMC of patients with sarcoidosis displayed significantly enhanced expression of IL27 and EBI3 mRNA (p = 0.020 and p = 0.037 respectively) compared to PBMCs from healthy controls. There was also significantly enhanced production of IL-27 by PBMC from patients with sarcoidosis compared to healthy controls in response to LPS stimulation (p = 0.027). IL6ST mRNA and IL6ST protein were significantly lower in patients with sarcoidosis (mRNA p = 0.0002; MFI p = 0.0015) whilst IL27RA protein levels were significantly higher in patients with sarcoidosis compared to healthy controls (MFI p < 0.0001). Plasma IL-35 protein levels did not differ between control and sarcoidosis subjects (p = 0.23).

CONCLUSION

These results suggest there may be exaggerated activation of IL-27 signalling in response to LPS in sarcoidosis.

Cellular Players in the Immunopathogenesis of Sarcoidosis

Current hypotheses on the pathogenesis of sarcoidosis assume that it is induced by a nondegradable antigen inducing immune reactions, which are mediated by a panel of immune cells of the innate and adoptive immune system. This immune reaction leads to an accumulation of immune cells that is mainly alveolar macrophages, T cells, and neutrophils in the lung. As the antigen persists and cannot be eliminated, the ongoing immune reaction results in granuloma formation and remodeling of the lung. The current review aims to elucidate the different roles of the cellular players in the immunopathogenesis of sarcoidosis.

Tissue-resident dendritic cells and diseases involving dendritic cell malfunction

Dendritic cells (DCs) control immune responses and are central to the development of immune memory and tolerance. DCs initiate and orchestrate immune responses in a manner that depends on signals they receive from microbes and cellular environment. Although DCs consist mainly of bone marrow-derived and resident populations, a third tissue-derived population resides the spleen and lymph nodes (LNs), different subsets of tissue-derived DCs have been identified in the blood, spleen, lymph nodes, skin, lung, liver, gut and kidney to maintain the tolerance and control immune responses. Tissue-resident DCs express different receptors for microbe-associated molecular patterns (MAMPs) and damage-associated molecular patterns (DAMPs), which were activated to promote the production of pro- or anti-inflammatory cytokines. Malfunction of DCs contributes to diseases such as autoimmunity, allergy, and cancer. It is therefore important to update the knowledge about resident DC subsets and diseases associated with DC malfunction.

Etiologies of Sarcoidosis

Since sarcoidosis was first described more than a century ago, the etiologic determinants causing this disease remain uncertain. Studies suggest that genetic, host immunologic, and environmental factors interact together to cause sarcoidosis. Immunologic characteristics of sarcoidosis include non-caseating granulomas, enhanced local expression of T helper-1 (and often Th17) cytokines and chemokines, dysfunctional regulatory T-cell responses, dysregulated Toll-like receptor signaling, and oligoclonal expansion of CD4+ T cells consistent with chronic antigenic stimulation. Multiple environmental agents have been suggested to cause sarcoidosis. Studies from several groups implicate mycobacterial or propionibacterial organisms in the etiology of sarcoidosis based on tissue analyses and immunologic responses in sarcoidosis patients. Despite these studies, there is no consensus on the nature of a microbial pathogenesis of sarcoidosis. Some groups postulate sarcoidosis is caused by an active viable replicating infection while other groups contend there is no clinical, pathologic, or microbiologic evidence for such a pathogenic mechanism. The authors posit a novel hypothesis that proposes that sarcoidosis is triggered by a hyperimmune Th1 response to pathogenic microbial and tissue antigens associated with the aberrant aggregation of serum amyloid A within granulomas, which promotes progressive chronic granulomatous inflammation in the absence of ongoing infection.

Lack of Association between Interleukin-18 –607 C/A Gene Polymorphism and Pulmonary Tuberculosis in Zahedan, Southeast Iran

Interleukin-18 (IL-18) plays a critical role in immune response, contributing to the pathogenesis and pathophysiology of infectious diseases. Polymorphisms in the IL-18 genes are known to influence expression levels and may be associated with outcome of infections. The objective of this study was to determine whether the presence of IL-18 polymorphisms –607 A/C (rs1946518) was associated with tuberculosis disease. We investigated the functional polymorphism of IL-18 (rs1946518) in 174 patients with pulmonary tuberculosis (PTB) and 177 healthy subjects. Genotype analysis was done using tetra amplification refractory mutation system-PCR (T-ARMS-PCR). The allelic and genotypic frequencies of the IL-18 polymorphism did not differ significantly between PTB and the controls. Our finding suggests that IL-18 polymorphism (rs1946518) may not be a risk factor for susceptibility to tuberculosis in a sample of Iranian population. Further studies are required to validate our findings.

The role of the mediators of inflammation in cancer development

Epigenetic disorders such as point mutations in cellular tumor suppressor genes, DNA methylation and post-translational modifications are needed to transformation of normal cells into cancer cells. These events result in alterations in critical pathways responsible for maintaining the normal cellular homeostasis, triggering to an inflammatory response which can lead the development of cancer. The inflammatory response is a universal defense mechanism activated in response to an injury tissue, of any nature, that involves both innate and adaptive immune responses, through the collective action of a variety of soluble mediators. Many inflammatory signaling pathways are activated in several types of cancer, linking chronic inflammation to tumorigenesis process. Thus, Inflammatory responses play decisive roles at different stages of tumor development, including initiation, promotion, growth, invasion, and metastasis, affecting also the immune surveillance. Immune cells that infiltrate tumors engage in an extensive and dynamic crosstalk with cancer cells, and some of the molecular events that mediate this dialog have been revealed. A range of inflammation mediators, including cytokines, chemokines, free radicals, prostaglandins, growth and transcription factors, microRNAs, and enzymes as, cyclooxygenase and matrix metalloproteinase, collectively acts to create a favorable microenvironment for the development of tumors. In this review are presented the main mediators of the inflammatory response and discussed the likely mechanisms through which, they interact with each other to create a condition favorable to development of cancer.

A brief exposure to tryptase or thrombin potentiates fibrocyte differentiation in the presence of serum or serum amyloid p

A key question in both wound healing and fibrosis is the trigger for the initial formation of scar tissue. To help form scar tissue, circulating monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes, but fibrocyte differentiation is strongly inhibited by the plasma protein serum amyloid P (SAP), and healthy tissues contain very few fibrocytes. In wounds and fibrotic lesions, mast cells degranulate to release tryptase, and thrombin mediates blood clotting in early wounds. Tryptase and thrombin are upregulated in wound healing and fibrotic lesions, and inhibition of these proteases attenuates fibrosis. We report that tryptase and thrombin potentiate human fibrocyte differentiation at biologically relevant concentrations and exposure times, even in the presence of concentrations of serum and SAP that normally completely inhibit fibrocyte differentiation. Fibrocyte potentiation by thrombin and tryptase is mediated by protease-activated receptors 1 and 2, respectively. Together, these results suggest that tryptase and thrombin may be an initial trigger to override SAP inhibition of fibrocyte differentiation to initiate scar tissue formation.

Interleukin-12 family cytokines and sarcoidosis

Sarcoidosis is a systemic granulomatous disease predominantly affecting the lungs. It is believed to be caused by exposure to pathogenic antigens in genetically susceptible individuals but the causative antigen has not been identified. The formation of non-caseating granulomas at sites of ongoing inflammation is the key feature of the disease. Other aspects of the pathogenesis are peripheral T-cell anergy and disease progression to fibrosis. Many T-cell-associated cytokines have been implicated in the immunopathogenesis of sarcoidosis, but it is becoming apparent that IL-12 cytokine family members including IL-12, IL-23, IL-27, and IL-35 are also involved. Although the members of this unique cytokine family are heterodimers of similar subunits, their biological functions are very diverse. Whilst IL-23 and IL-12 are pro-inflammatory regulators of Th1 and Th17 responses, IL-27 is bidirectional for inflammation and the most recent family member IL-35 is inhibitory. This review will discuss the current understanding of etiology and immunopathogenesis of sarcoidosis with a specific focus on the bidirectional impact of IL-12 family cytokines on the pathogenesis of sarcoidosis.

Safety and efficacy of ustekinumab or golimumab in patients with chronic sarcoidosis

Sarcoidosis is characterised by non-caseating granulomas that secrete pro-inflammatory cytokines, including interleukin (IL)-12, IL-23, and tumour necrosis factor (TNF)-α. Ustekinumab and golimumab are monoclonal antibodies that specifically inhibit IL-12/IL-23 and TNF-α, respectively. Patients with chronic pulmonary sarcoidosis (lung group) and/or skin sarcoidosis (skin group) received either 180 mg ustekinumab at week 0 followed by 90 mg every 8 weeks, 200 mg golimumab at week 0 followed by 100 mg every 4 weeks, or placebo. Patients underwent corticosteroid tapering between weeks 16 and 28. The primary end-point was week 16 change in percentage predicted forced vital capacity (ΔFVC % pred) in the lung group. Major secondary end-points were: week 28 for ΔFVC % pred, 6-min walking distance, St George's Respiratory Questionnaire (lung group), and Skin Physician Global Assessment response (skin group). At week 16, no significant differences were observed in ΔFVC % pred with ustekinumab (-0.15, p = 0.13) or golimumab (1.15, p = 0.54) compared with placebo (2.02). At week 28, there were no significant improvements in the major secondary end-points, although a nonsignificant numerically greater Skin Physician Global Assessment response was observed following golimumab treatment (53%) when compared with the placebo (30%). Serious adverse events were similar in all treatment groups. Although treatment was well tolerated, neither ustekinumab nor golimumab demonstrated efficacy in pulmonary sarcoidosis. However, trends towards improvement were observed with golimumab in some dermatological end-points.

Endostatin and cathepsin-V in bronchoalveolar lavage fluid of patients with pulmonary sarcoidosis

Recently, it has been reported that lack of cathepsins prevent the development of lung granulomas in a mouse model of Besnier-Boeck-Schaumann (BBS) disease, sarcoidosis. There is no data about cathepsin V (Cath V) in bronchoalveolar lavage fluid (BALF) in humans. Endostatin is a novel inhibitor of lung epithelial cells. The role of this protein in BBS is not determined. The aim of this study was to evaluate the concentration of endostatin, Cath V, and IL-18 in BALF of BBS patients. We studied 22 BBS patients (Stage 2). The control group consisted of 20 healthy subjects. Cath V concentration was lower in BBS than in healthy group (16.03±8.60 vs. 32.25±21.90 pg/ml, p=0.004). Both endostatin and IL-18 levels were higher in BBS than in the control group (0.88±0.30 vs. 0.29±0.04 ng/ml, p=0.028; 40.37±31.60 vs. 14.61±1.30 pg/ml, p=0.007, respectively). In BBS there were correlations between the levels of endostatin and IL-18 (r=0.74, p=0.001) as well as endostatin and DLCO (diffusing capacity for carbon monoxide) (r=-0.6, p=0.013). Receiver-operating characteristic (ROC) curves were applied to find the cut-off for the BALF levels of Cath V, endostatin, and IL-18. We conclude that Cath V and endostatin may represent an index of pulmonary sarcoidosis activity.

Inflammatory markers and pulmonary granuloma infiltration in sarcoidosis

BACKGROUND AND OBJECTIVE

Previous studies have demonstrated increases of inflammatory mediators in sarcoidosis while epidemiological studies have also demonstrated an association with increased fungi exposure. This study measured the level of β-glucan in the lungs and of inflammatory mediators in serum, and correlated both with the extent of pulmonary granuloma infiltration.

METHODS

This is a cross-sectional study of 98 patients with sarcoidosis and 26 controls. β-glucan, a cell wall constituent of fungi, was measured in bronchoalveolar lavage. Inflammatory mediator levels were determined in serum. The extent of granuloma infiltration was estimated on the chest X-ray. Exposure to fungi at home was determined by taking air samples in bedrooms and analysing for the presence of β-N-acetylhexosaminidase.

RESULTS

Significantly, higher levels of β-glucan were found in broncho-alveolar lavage in subjects with sarcoidosis as compared with controls. There were significant positive relationships between the extent of granuloma infiltration and the levels of the different inflammatory mediators, except for interleukin-10. Domestic fungal exposure was higher among subjects with sarcoidosis.

CONCLUSIONS

This is the first time that a specific agent, previously suspected to be related to the risk of sarcoidosis, has been detected in the lung of subjects with sarcoidosis and related to the levels of inflammatory mediators and the degree of home exposure to fungi. The results suggest that exposure to fungi should be explored when investigating patients with sarcoidosis.

Granuloma formation in pulmonary sarcoidosis

Sarcoidosis is a granulomatous disorder of unknown cause, affecting multiple organs, but mainly the lungs. The exact order of immunological events remains obscure. Reviewing current literature, combined with careful clinical observations, we propose a model for granuloma formation in pulmonary sarcoidosis. A tight collaboration between macrophages, dendritic cells, and lymphocyte subsets, initiates the first steps toward granuloma formation, orchestrated by cytokines and chemokines. In a substantial part of pulmonary sarcoidosis patients, granuloma formation becomes an on-going process, leading to debilitating disease, and sometimes death. The immunological response, determining granuloma sustainment is not well understood. An impaired immunosuppressive function of regulatory T cells has been suggested to contribute to the exaggerated response. Interestingly, therapeutical agents commonly used in sarcoidosis, such as glucocorticosteroids and anti-TNF agents, interfere with granuloma integrity and restore the immune homeostasis in autoimmune disorders. Increasing insight into their mechanisms of action may contribute to the search for new therapeutical targets in pulmonary sarcoidosis.

Carbon nanotube-induced pulmonary granulomatous disease: Twist1 and alveolar macrophage M1 activation

Sarcoidosis, a chronic granulomatous disease of unknown cause, has been linked to several environmental risk factors, among which are some that may favor carbon nanotube formation. Using gene array data, we initially observed that bronchoalveolar lavage (BAL) cells from sarcoidosis patients displayed elevated mRNA of the transcription factor, Twist1, among many M1-associated genes compared to healthy controls. Based on this observation we hypothesized that Twist1 mRNA and protein expression might become elevated in alveolar macrophages from animals bearing granulomas induced by carbon nanotube instillation. To address this hypothesis, wild-type and macrophage-specific peroxisome proliferator-activated receptor gamma (PPARγ) knock out mice were given oropharyngeal instillation of multiwall carbon nanotubes (MWCNT). BAL cells obtained 60 days later exhibited significantly elevated Twist1 mRNA expression in granuloma-bearing wild-type or PPARγ knock out alveolar macrophages compared to sham controls. Overall, Twist1 expression levels in PPARγ knock out mice were higher than those of wild-type. Concurrently, BAL cells obtained from sarcoidosis patients and healthy controls validated gene array data: qPCR and protein analysis showed significantly elevated Twist1 in sarcoidosis compared to healthy controls. In vitro studies of alveolar macrophages from healthy controls indicated that Twist1 was inducible by classical (M1) macrophage activation stimuli (LPS, TNFα) but not by IL-4, an inducer of alternative (M2) macrophage activation. Findings suggest that Twist1 represents a PPARγ-sensitive alveolar macrophage M1 biomarker which is induced by inflammatory granulomatous disease in the MWCNT model and in human sarcoidosis.

Potential prognostic value of intracellular cytokine detection by flow cytometry in pulmonary sarcoidosis

In pulmonary sarcoidosis, differential cytokine production in the lungs could be related to variable prognosis of patients at different stages of disease. Twenty patients with pulmonary sarcoidosis (10 at radiographic stage I and 10 at stages II-IV), as well as 10 age-matched healthy volunteers participated in the study. A 4-colour flow cytometric technique was used to measure interferon-γ (IFN-γ), interleukin (IL)-2, tumour necrosis factor-α (TNF-α), IL-4, and IL-13 production in phorbol myristate acetate (PMA)/ionomycin-stimulated CD4+ and CD8+ T cells from bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) of patients, and PB of control subjects. CD4+ T cells from patients showed higher expression of IFN-γ in BALF than in PB. Significant correlations were observed between the percentages of BALF CD4+ and CD8+ T cells expressing intracellular IFN-γ, IL-2, and TNF-α. Stage I patients had lower percentages of IFN-γ-producing CD4+ and CD8+ T cells, as well as TNF-α-producing CD8+ T cells, in BALF (but not in PB) than stage II-IV patients. A decreased TH1 and TC1 response was demonstrated in BALF of patients at stage I of disease, which could explain their anticipated better prognosis.

Disordered Toll-like receptor 2 responses in the pathogenesis of pulmonary sarcoidosis

In this study, we hypothesized that the granulomatous disorder sarcoidosis is not caused by a single pathogen, but rather results from abnormal responses of Toll-like receptors (TLRs) to conserved bacterial elements. Unsorted bronchoalveolar lavage (BAL) cells from patients with suspected pulmonary sarcoidosis and healthy non-smoking control subjects were stimulated with representative ligands of TLR-2 (in both TLR-2/1 and TLR-2/6 heterodimers) and TLR-4. Responses were determined by assessing resulting production of tumour necrosis factor (TNF)-α and interleukin (IL)-6. BAL cells from patients in whom sarcoidosis was confirmed displayed increased cytokine responses to the TLR-2/1 ligand 19-kDa lipoprotein of Mycobacterium tuberculosis (LpqH) and decreased responses to the TLR-2/6 agonist fibroblast stimulating ligand-1 (FSL)-1. Subsequently, we evaluated the impact of TLR-2 gene deletion in a recently described murine model of T helper type 1 (Th1)-associated lung disease induced by heat-killed Propionibacterium acnes. As quantified by blinded scoring of lung pathology, P. acnes-induced granulomatous pulmonary inflammation was markedly attenuated in TLR-2(-/-) mice compared to wild-type C57BL/6 animals. The findings support a potential role for disordered TLR-2 responses in the pathogenesis of pulmonary sarcoidosis.

Sarcoidosis: Immunopathogenesis and Immunological Markers

Sarcoidosis is a multisystem granulomatous disorder invariably affecting the lungs. It is a disease with noteworthy variations in clinical manifestation and disease outcome and has been described as an “immune paradox” with peripheral anergy despite exaggerated inflammation at disease sites. Despite extensive research, sarcoidosis remains a disease with undetermined aetiology. Current evidence supports the notion that the immune response in sarcoidosis is driven by a putative antigen in a genetically susceptible individual. Unfortunately, there currently exists no reliable biomarker to delineate the disease severity and prognosis. As such, the diagnosis of sarcoidosis remains a vexing clinical challenge. In this review, we outline the immunological features of sarcoidosis, discuss the evidence for and against various candidate etiological agents (infective and noninfective), describe the exhaled breath condensate, a novel method of identifying immunological biomarkers, and suggest other possible immunological biomarkers to better characterise the immunopathogenesis of sarcoidosis.

The role of PPARγ in carbon nanotube-elicited granulomatous lung inflammation

Background

Although granulomatous inflammation is a central feature of many disease processes, cellular mechanisms of granuloma formation and persistence are poorly understood. Carbon nanoparticles, which can be products of manufacture or the environment, have been associated with granulomatous disease. This paper utilizes a previously described carbon nanoparticle granuloma model to address the issue of whether peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear transcription factor and negative regulator of inflammatory cytokines might play a role in granulomatous lung disease. PPARγ is constitutively expressed in alveolar macrophages from healthy individuals but is depressed in alveolar macrophages of patients with sarcoidosis, a prototypical granulomatous disease. Our previous study of macrophage-specific PPARγ KO mice had revealed an intrinsically inflammatory pulmonary environment with an elevated pro-inflammatory cytokines profile as compared to wild-type mice. Based on such observations we hypothesized that PPARγ expression would be repressed in alveolar macrophages from animals bearing granulomas induced by MWCNT instillation.

Methods

Wild-type C57Bl/6 and macrophage-specific PPARγ KO mice received oropharyngeal instillations of multiwall carbon nanotubes (MWCNT) (100 μg). Bronchoalveolar lavage (BAL) cells, BAL fluids, and lung tissues were obtained 60 days post-instillation for analysis of granuloma histology and pro-inflammatory cytokines (osteopontin, CCL2, and interferon gamma [IFN-γ] mRNA and protein expression.

Results

In wild-type mice, alveolar macrophage PPARγ expression and activity were significantly reduced in granuloma-bearing animals 60 days after MWCNT instillation. In macrophage-specific PPARγ KO mice, granuloma formation was more extensive than in wild-type at 60 days after MWCNT instillation. PPARγ KO mice also demonstrated elevated pro-inflammatory cytokine expression in lung tissue, laser-microdissected lung granulomas, and BAL cells/fluids, at 60 days post MWCNT exposure.

Conclusions

Overall, data indicate that PPARγ deficiency promotes inflammation and granuloma formation, suggesting that PPARγ functions as a negative regulator of chronic granulomatous inflammation.