Immunological Evidence for the Role of Mycobacteria in Sarcoidosis: A Meta-Analysis

Sarcoidosis and its relation to other immune-mediated diseases: Epidemiological insights

Several epidemiological studies show a co-occurrence of sarcoidosis with other immune-mediated diseases (IMD). There are many similarities between sarcoidosis and IMDs in their geographical distribution and risk factors. Understanding these similarities and identifying the differences can help us to better understand sarcoidosis and put it into context with other IMDs. In this review, we present the current knowledge about the overlap between sarcoidosis and other IMDs derived from epidemiological studies. Epidemiologic methods utilize study design and statistical analysis to describe the patterns in data and, ideally, identify causal relationships between an exposure and a health outcome. We discuss how study design and analysis may affect the interpretation of epidemiological studies on this topic and highlight some theories that attempt to explain the relation between sarcoidosis and other IMDs.

A serum B-lymphocyte activation signature is a key distinguishing feature of the immune response in sarcoidosis compared to tuberculosis

Sarcoidosis and tuberculosis (TB) are two granulomatous diseases that often share overlapping clinical features, including uveitis. We measured 368 inflammation-related proteins in serum in both diseases, with and without uveitis from two distinct geographically separated cohorts: sarcoidosis from the Netherlands and TB from Indonesia. A total of 192 and 102 differentially expressed proteins were found in sarcoidosis and active pulmonary TB compared to their geographical healthy controls, respectively. While substantial overlap exists in the immune-related pathways involved in both diseases, activation of B cell activating factor (BAFF) signaling and proliferation-inducing ligand (APRIL) mediated signaling pathways was specifically associated with sarcoidosis. We identified a B-lymphocyte activation signature consisting of BAFF, TNFRSF13B/TACI, TRAF2, IKBKG, MAPK9, NFATC1, and DAPP1 that was associated with sarcoidosis, regardless of the presence of uveitis. In summary, a difference in B-lymphocyte activation is a key discriminative immunological feature between sarcoidosis/ocular sarcoidosis (OS) and TB/ocular TB (OTB).

[Analysis of 14 cases of sarcoidosis of head and neck]

Objective:To explore the clinical characteristics of sarcoidosis of head and neck symptoms, and to summarize the diagnosis and treatment experience. Methods:A retrospective study was conducted on patients with nodular disease with main symptoms in the head and neck who visited Henan Provincial People's Hospital from January 2020 to August 2023. The clinical data including symptom characteristics, pathological characteristics, treatment methods, and prognosis were analyzed. Results:A total of 14 patients were included, with 4 males（28.6%） and 10 females（71.4%）, age ranged from 11 to 71 years, with an average age of（52.0±15.8） years. The lesions were located in the parotid gland in 2 cases and the neck in 12 cases. Twelve cases underwent neck mass resection surgery, and 2 cases underwent ultrasound-guided core biopsy of parotid gland tumor and postoperative pathological diagnosis was confirmed in all cases. Four cases received steroid treatment postoperatively, and showed good prognosis with reduced lesion size after 3 months. Three cases did not take medication and the lesions continued to persist, causing discomfort. Seven cases did not take medication postoperatively, and the lesions expanded with multi-organ progression. Conclusion:Patients with head and neck sarcoidosis are rare in clinical practice, and it is prone to misdiagnosis and missed diagnosis. Steroid therapy can achieve good therapeutic effects.

The role of the host-microbiome and metabolomics in sarcoidosis

Sarcoidosis is a complex inflammatory fibrotic disease that affects multiple organ systems. It is characterized by the infiltration of lymphocytes and mononuclear phagocytes, which form non-caseating granulomas in affected organs. The lungs and intrathoracic lymph nodes are the most commonly affected organs. The underlying cause of sarcoidosis is unknown, but it is believed to occur in genetically predisposed individuals who are exposed to pathogenic organisms, environmental contaminants, or self and non-self-antigens. Recent research has suggested that the microbiome may play a role in the development of respiratory conditions, including sarcoidosis. Additionally, metabolomic studies have identified potential biomarkers for monitoring sarcoidosis progression. This review will focus on recent microbiome and metabolomic findings in sarcoidosis, with the goal of shedding light on the pathogenesis and possible diagnostic and therapeutic approaches.

Pulmonary fibrosis in sarcoidosis

Sarcoidosis may progress to pulmonary fibrosis in 5% of patients with significantly increased mortality. Histopathology shows fibrosis in a lymphangitic pattern surrounding the granulomas. Th1 to Th2 shift in environment along with angiogenesis is implicated in exuberant fibrosis. Clinical features include dyspnea, cough, and frequently with pulmonary function tests showing a mixed ventilatory defect with severely decreased diffusion capacity of carbon monoxide.  Serologic markers including soluble interleukin 2 receptor, chitotriosidase and kern von den lunges 6, and chemokine ligand 18 are elevated and implicated in progression of disease. CT imaging shows fibrosis along bronchovascular bundles with reticulations, traction bronchiectasis and honeycombing predominantly in the upper and central distribution. Complications include sarcoidosis-associated pulmonary hypertension (SAPH) and chronic pulmonary aspergillosis. Treatment involves glucocorticoids and steroid-sparing agents in the presence of active granulomas. Anti-fibrotic agents such as pirfenidone and nintedanib have been shown to slow down pulmonary function decline in randomized clinical trials involving sarcoidosis-associated pulmonary fibrosis. Transplant workup is indicated in New York Heart Association class III or IV with similar success rates as in other lung transplant patients.

Pulmonary Sarcoidosis: Experimental Models and Perspectives of Molecular Diagnostics Using Quantum Dots

Sarcoidosis is a complex inflammatory multisystem disease of unknown etiology that is characterised by epithelioid cell granulomatous lesions affecting various organs, mainly the lungs. In general, sarcoidosis is asymptomatic, but some cases result in severe complications and organ failure. So far, no accurate and validated modelling for clinical and pathohistological manifestations of sarcoidosis is suggested. Moreover, knowledge about disease-specific diagnostic markers for sarcoidosis is scarce. For instance, pulmonary granulomatosis is associated with the upregulated production of proinflammatory molecules: TNF-α, IL-6, CXCL1, CCL2, CCL18, CD163, serum angiotensin-converting enzyme (sACE), lysozyme, neopterin, and serum amyloid A (SAA). Quantum dots (QDs) are widely applied for molecular diagnostics of various diseases. QDs are semiconductor nanoparticles of a few nanometres in size, made from ZnS, CdS, ZnSe, etc., with unique physical and chemical properties that are useful for the labelling and detection in biological experiments. QDs can conjugate with various antibodies or oligonucleotides, allowing for high-sensitivity detection of various targets in organs and cells. Our review describes existing experimental models for sarcoidosis (in vitro, in vivo, and in silico), their advantages and restrictions, as well as the physical properties of quantum dots and their potential applications in the molecular diagnostics of sarcoidosis. The most promising experimental models include mice with TSC2 deletion and an in silico multiscale computational model of sarcoidosis (SarcoidSim), developed using transcriptomics and flow cytometry of human sarcoid biopsies. Both models are most efficient to test different candidate drugs for sarcoidosis.

The Overlap of Kidney Failure in Extrapulmonary Sarcoidosis in Children-Case Report and Review of Literature

Sarcoidosis is a non-necrotizing granulomatous inflammatory multisystemic disorder of unknown etiology. In children, as in adults, it can involve a few or all organ systems to a varying extent and degree, entailing multisystemic manifestations. Kidney involvement in pediatric-onset adult-type sarcoidosis is rare, with a wide range of renal manifestations, most of them related to calcium metabolism. Children with renal sarcoidosis tend to be more symptomatic than adults, although male patients have a higher prevalence. We present the case of a 10-year-old boy who presented with advanced renal failure with nephrocalcinosis and important hepatosplenomegaly. The diagnosis was established by histopathological examination, with consequent cortisone therapy and hemodialysis. This review emphasizes that sarcoidosis should be considered in the differential diagnosis of pediatric patients with acute kidney insufficiency or chronic kidney disease of an unknown etiology. As far as we know, this is the first study regarding extrapulmonary sarcoidosis in children from Romania.

Head and Neck Tuberculosis associated to Sarcoidosis : A Case Report

The distinction between tuberculosis and sarcoidosis presents sometimes a clinical challenge. Their sequential occurrence in the same patient is uncommon. We present the case of a 42-year-old female with a proven diagnosis of tuberculous lymphadenitis who has developed successively nasal tuberculosis and pulmonary sarcoidosis respectively after 10 and 14 months of antituberculosis treatment. The patient presented with bilateral cervical lymphadenopathy. Tuberculin skin test was negative. Chest radiography was normal. An excision biopsy was taken and histopathological examination established tuberculosis diagnosis. Therapy with antituberculosis drugs was started, and cervical lymphadenopathy showed progressive resolution. Subsequently, nearly 10 months after, the patient developed new cervical lymphadenopathies and nasal obstruction. Tuberculosis of the nasal mucosa was confirmed by biopsy. Antituberclosis bitherapy was enhanced by ofloxacin and ethambutol. Thoracic CT scan showed several nodular elements in both lungs, with bilateral enlarged mediastinal adenopathy. Bronchoalveolar lavage showed a lymphocytic alveolitis with a CD4/CD8 ratio of 5, consistent with the diagnosis of pulmonary sarcoidosis. Corticosteroid treatment, in form of oral prednisolone was introduced, 3 months after sarcoidosis diagnosis have been setteled; because of pulmonary fibrosis noticed on thoracic CT. Systemic corticotherapy was continued for a further period of 3 years, until all the lesions cleared out. The present case emphasizes the possible association between tuberculosis and sarcoidosis.

Sarcoidosis: Epidemiology and clinical insights

Sarcoidosis is characterized by noncaseating granulomas which form in almost any part of the body, primarily in the lungs and/or thoracic lymph nodes. Environmental exposures in genetically susceptible individuals are believed to cause sarcoidosis. There is variation in incidence and prevalence by region and race. Males and females are almost equally affected, although disease peaks at a later age in females than in males. The heterogeneity of presentation and disease course can make diagnosis and treatment challenging. Diagnosis is suggestive in a patient if one or more of the following is present: radiologic signs of sarcoidosis, evidence of systemic involvement, histologically confirmed noncaseating granulomas, sarcoidosis signs in bronchoalveolar lavage fluid (BALF), and low probability or exclusion of other causes of granulomatous inflammation. No sensitive or specific biomarkers for diagnosis and prognosis exist, but there are several that can be used to support clinical decisions, such as serum angiotensin-converting enzyme levels, human leukocyte antigen types, and CD4 Vα2.3+ T cells in BALF. Corticosteroids remain the mainstay of treatment for symptomatic patients with severely affected or declining organ function. Sarcoidosis is associated with a range of adverse long-term outcomes and complications, and with great variation in prognosis between populations. New data and technologies have moved sarcoidosis research forward, increasing our understanding of the disease. However, there is still much left to be discovered. The pervading challenge is how to account for patient variability. Future studies should focus on how to optimize current tools and develop new approaches so that treatment and follow-up can be targeted to individuals with more precision.

FDG PET/CT Imaging of Sarcoidosis

Sarcoidosis is a multisystemic granulomatous disease of unknown etiology. The diagnostic can be made by histological identification of non-caseous granuloma or by a combination of clinical criteria. Active inflammatory granuloma can lead to fibrotic damage. Although 50% of cases resolve spontaneously, systemic treatments are often necessary to decrease symptoms and avoid permanent organ dysfunction, notably in cardiac sarcoidosis. The course of the disease can be punctuated by exacerbations and relapses and the prognostic depends mainly on affected sites and patient management. FDG-PET/CT along with newer FDG-PET/MR have emerged as key imaging modalities in sarcoidosis, namely for certain diagnostic purposes, staging and biopsy guiding. By identifying with a high sensitivity inflammatory active granuloma, FDG hybrid imaging is a main prognostic tool and therapeutic ally in sarcoidosis. This review aims to highlight the actual critical roles of hybrid PET imaging in sarcoidosis and display a brief perspective for the future which appears to include other radiotracers and artificial intelligence applications.

Case Report: Multiple Ocular Manifestations Assisted the Diagnosis of Systemic Sarcoidosis

SIGNIFICANCE

Sarcoidosis is a variable, multisystem granulomatous disease which can affect many organs including the lungs, lymph nodes and eyes. It is difficult to differentiate sarcoidosis and tuberculosis due to their similar clinical and pathological features.

PURPOSE

To describe a sarcoidosis case with typical ocular and systemic manifestations combined with suspected tuberculosis infection.

CASE REPORT

A 30-year-old Chinese male, initially diagnosed with tuberculosis, presented with typical ocular sarcoidosis during anti-tuberculosis therapy. The ocular surface, anterior chamber, anterior chamber angle, ciliary body, vitreous, optic disc and lacrimal gland of the patient all exhibited manifestations of sarcoidosis, although optic disc involvement has rarely been reported. Typical ocular sarcoidosis manifestations and positive responses to corticosteroid therapy of the patient helped us reach the diagnosis of systemic sarcoidosis. The patient was followed up for 48 months and showed significant improvement of miliary nodules and lymph nodes in both lungs. However, the appearance of uveitis in the right eye persisted due to non-adherence with steroid treatment.

CONCLUSIONS

This case shows the importance of ophthalmic evaluation in the diagnosis and management of sarcoidosis, and supports a possible role of mycobacterium tuberculosis in the pathogenesis of sarcoidosis.

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.

Characteristics and management of ocular sarcoidosis

Sarcoidosis is a chronic inflammatory disease of unknown etiology that affects many systemic organs, including the eye. The eye is the second most frequently affected organ in patients with sarcoidosis after lung disease. Approximately 30-50% of patients with systemic sarcoidosis develop uveitis, which is a sight-threatening intraocular inflammatory disorder. Sarcoidosis is the leading cause of uveitis in Japan and is one of the major clinical entities in many countries. Therefore, uveitis in association with sarcoidosis (ocular sarcoidosis) is considered essential in clinical practice in ophthalmology. The current review focuses on distinguishing features of ocular sarcoidosis, diagnosis, management, and discussion of the etiology of ocular sarcoidosis.

A Primer on the Clinical Aspects of Sarcoidosis for the Basic and Translational Scientist

The immunopathogenesis of sarcoidosis remains unclear. This failure in understanding has been clinically impactful, as it has impeded the accurate diagnosis, treatment, and prevention of this disease. Unraveling the mechanisms of sarcoidosis will require input from basic and translational scientists. In order to reach this goal, scientists must have a firm grasp of the clinical aspects of the disease, including its diagnostic criteria, the immunologic defects, clinical presentations, response to therapy, risk factors, and clinical course. This manuscript will provide an overview of the clinical aspects of sarcoidosis that are particularly relevant for the basic and translational scientist. The variable phenotypic expression of the disease will be described, which may be integral in identifying immunologic disease mechanisms that may be relevant to subgroups of sarcoidosis patients. Data concerning treatment and risk factors may yield important insights concerning germane immunologic pathways involved in the development of disease. It is hoped that this manuscript will stimulate communication between scientists and clinicians that will eventually lead to improved care of sarcoidosis patients.

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

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

Immunohistochemical Detection of Potential Microbial Antigens in Granulomas in the Diagnosis of Sarcoidosis

Sarcoidosis may have more than a single causative agent, including infectious and non-infectious agents. Among the potential infectious causes of sarcoidosis, Mycobacterium tuberculosis and Propionibacterium acnes are the most likely microorganisms. Potential latent infection by both microorganisms complicates the findings of molecular and immunologic studies. Immune responses to potential infectious agents of sarcoidosis should be considered together with the microorganisms detected in sarcoid granulomas, because immunologic reactivities to infectious agents reflect current and past infection, including latent infection unrelated to the cause of the granuloma formation. Histopathologic data more readily support P. acnes as a cause of sarcoidosis compared with M. tuberculosis, suggesting that normally symbiotic P. acnes leads to granuloma formation in some predisposed individuals with Th1 hypersensitivity against intracellular proliferation of latent P. acnes, which may be triggered by certain host or drug-induced conditions. Detection of bacterial nucleic acids in granulomas does not necessarily indicate co-localization of the bacterial proteins in the granulomas. In the histopathologic diagnosis of sarcoidosis, M. tuberculosis-associated and P. acnes-associated sarcoidosis will possibly be differentiated in some patients by immunohistochemistry with appropriate antibodies that specifically react with mycobacterial and propionibacterial antigens, respectively, for each etiology-based diagnosis and potential antimicrobial intervention against sarcoidosis.

Distinguishing Blau Syndrome from Systemic Sarcoidosis

PURPOSE OF REVIEW

The purpose of this review is to provide a framework to distinguish Blau syndrome/Early Onset Sarcoidosis and Sarcoidosis clinically. We also discuss relevant differences in genetics, pathogenesis, and management of these diseases.

RECENT FINDINGS

Blau syndrome and Sarcoidosis share the characteristic histologic finding of noncaseating granulomas as well as some similar clinical characteristics; nevertheless, they are distinct entities with important differences between them. Blau syndrome and Early Onset Sarcoidosis are due to one of numerous possible gain-of-function mutations in NOD2, commonly presenting before age 5 with a triad of skin rash, arthritis, and uveitis. However, as more cases are reported, expanded clinical manifestations have been described. In systemic Sarcoidosis, there are numerous susceptibility genes that have been identified, and disease is thought to result from an environmental exposure in a genetically susceptible host. It most often presents with constitutional symptoms and pulmonary involvement and typically affects adolescents and adults. This paper reviews the similarities and differences between Blau syndrome and Sarcoidosis. We also discuss the importance of distinguishing between them, particularly with regard to prognosis and outcomes.

Simultaneous testing of immunological sensitization to multiple antigens in sarcoidosis reveals an association with inorganic antigens specifically related to a fibrotic phenotype

Organic and inorganic antigens were studied simultaneously in the same cohort of sarcoidosis patients to investigate whether correlations between clinical characteristics and immunological sensitization could reveal new phenotypes. Sensitization to antigens of mycobacteria, Propionibacterium acnes catalase and vimentin was investigated in 201 sarcoidosis and 51 obstructive sleep apnoea patients, serving as control group. Sensitization to aluminium, beryllium, silica and zirconium was also studied in 105 of the sarcoidosis patients and in 24 of the controls. A significantly higher percentage of sarcoidosis patients (27·6%) than controls (4·2%) had an immunological response to metals or silica (P = 0·014). A higher percentage of these sarcoidosis patients showed fibrosis on chest X-ray 5 years after the diagnosis (69·2 versus 30·3%, P = 0·016). No significant differences in mycobacterial or vimentin enzyme-linked immunospot (ELISPOT) assay results were observed between sarcoidosis and control patients. A significantly lower percentage of sarcoidosis patients (3·5%) than control patients (15·7%) had a positive ELISPOT for P. acnes catalase (P = 0·003). However, sarcoidosis patients sensitized to P. acnes catalase were more likely to have skin involvement, while sarcoidosis patients sensitized to mycobacterial antigens were more likely to have cardiac involvement. Our study suggests a more prominent role for inorganic triggers in sarcoidosis pathogenesis than previously thought. Immunological sensitization to inorganic antigens was associated with development of fibrotic sarcoidosis. No association was found between sensitization to bacterial antigens or vimentin and sarcoidosis in Dutch patients. However, our data suggest that trigger-related phenotypes can exist in the heterogeneous population of sarcoidosis patients.

Latent tuberculosis infection associates with cardiac involvement in patients with sarcoidosis

BACKGROUND

Sarcoidosis is a systemic disease characterized by formation of non-caseating granulomas. About 5% of patients have symptoms of cardiac sarcoidosis. Identification of cardiac involvement is important since it is a major cause of death. Mycobacterial antigens have been linked to sarcoidosis pathogenesis. Previous findings suggest that a latent tuberculosis infection (LTBI) might associate with development of cardiac involvement in patients with sarcoidosis. The aim of the present study was to further evaluate these findings in another cohort of cardiac sarcoidosis patients.

METHODS

Interferon release assays (IGRAs) or tuberculin skin tests (TST) were analysed in a cohort of cardiac sarcoidosis patients (n=103) and compared to non-cardiac sarcoidosis patients (n=153).

RESULTS

In the cohort of patients with cardiac sarcoidosis, 7 could be diagnosed with a LTBI (6.8%) compared to only one of the non-cardiac patients (0.7%), p = 0.008.

CONCLUSIONS

To conclude, we were able to show an association between a LTBI and cardiac involvement in patients with sarcoidosis. Future research is however required to unravel the mechanism involved in this association. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (3): e2020005).

Case Report: Co-existence of sarcoidosis and Takayasu arteritis

Takayasu arteritis is a rare systemic large vessel vasculitis affecting the aorta and its branches. Sarcoidosis, too, is an inflammatory disease. Both entities are granulomatous conditions with a questionable association in their etiopathogenesis. Only a few cases of their coexistence have been reported in the literature. To our knowledge, no such cases have been reported from Nepal. We report a Nepalese woman who presented with non-productive cough, progressive shortness of breath and chest tightness of 3 years duration. She had a history of recurrent bilateral granulomatous uveitis over the previous 3 years. Examination revealed clubbing of digits, absent pulses over the left radial, ulnar and brachial arteries, and a weak pulse over the right arm including the bilateral carotid arteries. Pulmonary function test showed restrictive pattern, a high-resolution computed tomography (HRCT) scan of the chest revealed findings suggestive of pulmonary sarcoidosis. A CT angiogram suggested large vessel vasculitis. Bronchoscopy with biopsy revealed granulomatous inflammation, negative for malignancy and tuberculosis. She was hence, diagnosed with co-existing Takayasu arteritis and sarcoidosis, and treated with Prednisolone 60 mg once daily with dramatic improvement over 4 days and was discharged stable on domiciliary oxygen. She is currently on azathioprine 50 mg, prednisolone 10 mg without the need for supplemental oxygen. This case report highlights the importance of a proper physical examination as a guide to the use of modern technology in making a correct diagnosis. Furthermore, in countries where tuberculosis is endemic, it should always come as the most important differential diagnosis of granulomatous inflammation.

Indirect pathological indicators for cardiac sarcoidosis on endomyocardial biopsy

BACKGROUND

The definitive pathologic diagnosis of cardiac sarcoidosis requires observation of a granuloma in the myocardial tissue. It is common, however, to receive a "negative" report for a clinically probable case. We would like to advise pathologists and clinicians on how to interpret "negative" biopsies.

METHODS

Our study samples were 27 endomyocardial biopsies from 25 patients, three cardiac transplantation and an autopsied heart with suspected cardiac sarcoidosis. Pathologic, radiologic, and clinical features were compared.

RESULTS

The presence of micro-granulomas or increased histiocytic infiltration was always (6/6 or 100%) associated with fatty infiltration and confluent fibrosis, and they showed radiological features of sarcoidosis. Three of five cases (60%) with fatty change and confluent fibrosis were probable for cardiac sarcoidosis on radiology. When either confluent fibrosis or fatty change was present, one-third (3/9) were radiologically probable for cardiac sarcoidosis. We interpreted cases with micro-granuloma as positive for cardiac sarcoidosis (five of 25, 20%). Cases with both confluent fibrosis and fatty change were interpreted as probable for cardiac sarcoidosis (seven of 25, 28%). Another 13 cases, including eight cases with either confluent fibrosis or fatty change, were interpreted as low probability based on endomyocardial biopsy.

CONCLUSIONS

The presence of micro-granuloma could be an evidence for positive diagnosis of cardiac sarcoidosis. Presence of both confluent fibrosis and fatty change is necessary for probable cardiac sarcoidosis in the absence of granuloma. Either of confluent fibrosis or fatty change may be an indirect pathological evidence but they are interpreted as nonspecific findings.

Environmental Risk Factors for Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease that may affect any body organ. Sarcoidosis is associated with many environmental and occupational exposures. Because the exact immunopathogenesis of sarcoidosis is unknown, it is not known whether these exposures are truly causing sarcoidosis, rendering the immune system more susceptible to the development of sarcoidosis, exacerbating subclinical cases of sarcoidosis, or causing a granulomatous condition distinct from sarcoidosis. This manuscript outlines what is known about the immunopathogenesis of sarcoidosis and postulates mechanisms whereby these exposures could cause or exacerbate the disease. We also describe the varied environmental and occupational exposures that have been associated with sarcoidosis. This includes potential infectious exposures such as mycobacteria and Propionibacterium acnes, a skin commensal bacterium, as well as non-infectious environmental exposures including inhaled bioaerosols, metal dusts and products of combustion. Further insights concerning the relationship of environmental exposures to the development of sarcoidosis may have a major impact on the prevention and treatment of this enigmatic disease.

Anti-inflammatory effects of α-MSH through p-CREB expression in sarcoidosis like granuloma model

Lung inflammation due to sarcoidosis is characterized by a complex cascade of immunopathologic events, including leukocyte recruitment and granuloma formation. α-melanocyte stimulating hormone (α-MSH) is a melanocortin signaling peptide with anti-inflammatory properties. We aimed to evaluate the effects of α-MSH in a novel in vitro sarcoidosis model. An in vitro sarcoidosis-like granuloma model was developed by challenging peripheral blood mononuclear cells (PBMCs) derived from patients with confirmed treatment-naïve sarcoidosis with microparticles generated from Mycobacterium abscessus cell walls. Unchallenged PBMCsand developed granulomas were treated daily with 10 μM α-MSH or saline as control. Cytokine concentrations in supernatants of culture and in cell extracts were measured using Illumina multiplex Elisa and western blot, respectively. Gene expression was analyzed using RNA-Seq and RT-PCR. Protein secretion and gene expression of IL-7, IL-7R, IFN-γ, MC1R, NF-κB, phosphorylated NF-κB (p-NF-κB), MARCO, and p-CREB were measured with western blot and RNAseq. A significant increase in IL-7, IL-7R, and IFN-γ protein expression was found in developed granulomas comparing to microparticle unchallenged PBMCs. IL-7, IL-7R, and IFN-γ protein expression was significantly reduced in developed granulomas after exposure to α-MSH compared with saline treated granulomas. Compared with microparticle unchallenged PBMCs, total NF-κB and p-NF-κB were significantly increased in developed granulomas, while expression of p-CREB was not changed. Treatment with α-MSH promoted a significantly higher concentration of p-CREB in granulomas. The anti-inflammatory effects of α-MSH were blocked by specific p-CREB inhibition. α-MSH has anti-inflammatory properties in this in vitro granuloma model, which is an effect mediated by induction of phosphorylation of CREB.

Case Report: Co-existence of sarcoidosis and Takayasu arteritis

Takayasu arteritis is a rare systemic large vessel vasculitis affecting the aorta and its branches. Sarcoidosis, too, is an inflammatory disease. Both entities are granulomatous conditions with a question of possible linkquestionable association in their etiopathogenesis. Only a few cases of their coexistence have been reported in the literature. To our knowledge, no such cases have been reported from Nepal. We report a Nepalese woman who presented with non-productive cough, progressive shortness of breath and chest tightness of 3 years duration. She had a history of recurrent bilateral granulomatous uveitis over the previous 3 years. Examination revealed clubbing of digits, absent pulses over the left radial, ulnar and brachial arteries, and a weak pulse over the right arm including the bilateral carotid arteries. Pulmonary function test showed restrictive pattern, a high-resolution computed tomography (HRCT) scan of the chest revealed findings suggestive of pulmonary sarcoidosis. A CT aortogram suggested large vessel vasculitis. Bronchoscopy with biopsy revealed granulomatous inflammation, negative for malignancy and tuberculosis. She was hence, diagnosed with co-existing Takayasu arteritis and sarcoidosis, and treated with Prednisolone 60 mg once daily with dramatic improvement over 4 days and was discharged stable on domiciliary oxygen. She is currently on azathioprine 50 mg, prednisolone 10 mg without the need for supplemental oxygen. This case report highlights the importance of a proper physical examination as a guide to the use of modern technology in making a correct diagnosis. Furthermore, in countries where tuberculosis is endemic, it should always come as the most important differential diagnosis of granulomatous inflammation.

PPARγ Deficiency in Carbon Nanotube-elicited Granulomatous Inflammation Promotes a Th17 Response to a Microbial Antigen

BACKGROUND

The pathological consequences of interaction between environmental carbon pollutants and microbial antigens have not been fully explored. We developed a murine model of multi-wall carbon nanotube (MWCNT)-elicited granulomatous disease which bears a striking resemblance to sarcoidosis, a human granulomatous disease. Because of reports describing lymphocyte reactivity to mycobacterial antigens in sarcoidosis patients, we hypothesized that addition of mycobacterial antigen (ESAT-6) to MWCNT might elicit activation in T cells.

METHODS

Macrophage-specific peroxisome-proliferator-activated receptor gamma (PPARγ) knock out (KO) mice were studied along with wild-type mice because our previous report indicated PPARγ deficiency in sarcoidosis alveolar macrophages. MWCNT+ESAT-6 were instilled into mice. Controls received vehicle (surfactant-PBS) or ESAT-6 and were evaluated 60 days post-instillation. As noted in our recent publication, lung tissues from PPARγ KO mice instilled with MWCNT+ESAT-6 yielded more intensive pathophysiology, with elevated fibrosis.

RESULTS

Inspection of mediastinal lymph nodes (MLN) revealed no granulomas but deposition of MWCNT. MLN cell counts were higher in PPARγ KO than in wild-type instilled with MWCNT+ESAT-6. Moreover, the CD4:CD8 T cell ratio, a major clinical metric for human disease, was increased in PPARγ KO mice. Bronchoalveolar lavage (BAL) cells from PPARγ KO mice instilled with MWCNT+ESAT-6 displayed increased Th17 cell markers (RORγt, IL-17A, CCR6) which associate with elevated fibrosis.

CONCLUSION

These findings suggest that PPARγ deficiency in macrophages may promote ESAT-6-associated T cell activation in the lung, and that the MWCNT+ESAT-6 model may offer new insights into pathways of lymphocyte-mediated sarcoidosis histopathology.

Are infectious diseases risk factors for sarcoidosis or a result of reverse causation? Findings from a population-based nested case-control study

Findings from molecular studies suggesting that several infectious agents cause sarcoidosis are intriguing yet conflicting and likely biased due to their cross-sectional design. As done in other inflammatory diseases to overcome this issue, prospectively-collected register data could be used, but reverse causation is a threat when the onset of disease is difficult to establish. We investigated the association between infectious diseases and sarcoidosis to understand if they are etiologically related. We conducted a nested case-control study (2009-2013) using incident sarcoidosis cases from the Swedish National Patient Register (n = 4075) and matched general population controls (n = 40,688). Infectious disease was defined using inpatient/outpatient visits and/or antimicrobial dispensations starting 3 years before diagnosis/matching. Adjusted odds ratios (aOR) of sarcoidosis were estimated using conditional logistic regression and tested for robustness assuming the presence of reverse causation bias. The aOR of sarcoidosis associated with history of infectious disease was 1.19 (95% confidence interval [CI] 1.09, 1.29; 21% vs. 16% exposed cases and controls, respectively). Upper respiratory and ocular infections conferred the highest OR. Findings were similar when we altered the infection definition or varied the infection-sarcoidosis latency period (1-7 years). In bias analyses assuming one in 10 infections occurred because of preclinical sarcoidosis, the observed association was completely attenuated (aOR 1.02; 95% CI 0.90, 1.15). Our findings, likely induced by reverse causation due to preclinical sarcoidosis, do not support the hypothesis that common symptomatic infectious diseases are etiologically linked to sarcoidosis. Caution for reverse causation bias is required when the real disease onset is unknown.

PET/CT Imaging in Soft Tissue Infection and Inflammation-An Update

Nuclear medicine procedures, including Ga-67 and labeled leucocyte SPECT/CT as well as PET/CT using 18F-FDG and recently Ga-68 tracers, have found extensive applications in the assessment of infectious and inflammatory processes in general and in soft tissues in particular. Recent published data focus on summarizing the available imaging information with the purpose of providing the referring clinicians with optimized evidence based results. Guidelines and/or recommendations of clinical societies have incorporated nuclear medicine tests (using both labeled leucocytes and FDG) in their suggested work-up for evaluation of infective endocarditis and in certain patients with suspected vascular graft infections. Joint guidelines of the European and American nuclear medicine societies include fever of unknown origin, sarcoidosis, and vasculitis among the major clinical indications that will benefit from nuclear medicine procedures, specifically from FDG PET/CT. Limitations and pitfalls for the use of radiotracers in assessment of infection and inflammation can be related to patient conditions (eg, diabetes mellitus), or to the biodistribution of a specific radiopharmaceutical. Limited presently available data on the use of functional and/or metabolic monitoring of response to infectious and inflammatory processes to treatment and with respect to the effect of drugs such as antibiotics and glucocorticoids on the imaging patterns of these patients need further confirmation.

Identification of Mycobacterium tuberculosis and non-tuberculous mycobacteria from cutaneous sarcoidosis lesions by reverse blot hybridization assay

While the etiology of sarcoidosis remains uncertain, mycobacteria have been suggested as a causative infectious agent. To investigate the causal relationship between mycobacteria and sarcoidosis, we performed a reverse blot hybridization assay (REBA) to identify mycobacteria from the skin samples of nine patients with sarcoidosis. Six of the nine samples were shown to be positive for mycobacteria by REBA, including Mycobacterium tuberculosis and non-tuberculous mycobacteria. This is the first study to identify mycobacteria from the skin samples of sarcoidosis patients using REBA, and our results could strengthen the etiologic association between mycobacteria and sarcoidosis.

Musculoskeletal Manifestations of Sarcoidosis: A Review Article

BACKGROUND

Sarcoidosis is a multisystem inflammatory disease with an etiology that is not clearly understood. Amongst the different organs that may be affected, the lungs are the most common. Musculoskeletal manifestations of the disease are uncommon.

OBJECTIVES

They include arthropathy, bone lesions, or myopathy, all of which may occur as initial symptoms or develop during the course of the disease.

METHODS

Articular involvement my present as arthralgia or arthritis. Skeletal complications usually develop in the chronic state of the disease. Muscular disease is rare and usually asymptomatic. Appropriate imaging modalities including X-ray, MRI, FDG-PET/CT assist in the diagnosis of rheumatic sarcoidosis. However, biopsy is necessary for definite diagnosis.

RESULT AND CONCLUSION

In most cases of musculoskeletal involvement, NSAIDs and corticosteroids are sufficient for symptomatic management. For more resistant cases immunosuppressive drugs (i.e., methotrexate) and TNF- inhibitors are used. Our aim is to review various types of musculoskeletal involvement in sarcoidosis and their existing treatment options.

Host-microbe interactions in the pathogenesis and clinical course of sarcoidosis

Sarcoidosis is a rare inflammatory disease characterized by the development of granulomas in various organs, especially in the lungs and lymph nodes. Clinics of the disease largely depends on the organ involved and may range from mild symptoms to life threatening manifestations. Over the last two decades, significant advances in the diagnosis, clinical assessment and treatment of sarcoidosis have been achieved, however, the precise etiology of this disease remains unknown. Current evidence suggests that, in genetically predisposed individuals, an excessive immune response to unknown antigen/s is crucial for the development of sarcoidosis. Epidemiological and microbiological studies suggest that, at least in a fraction of patients, microbes or their products may trigger the immune response leading to sarcoid granuloma formation. In this article, we discuss the scientific evidence on the interaction of microbes with immune cells that may be implicated in the immunopathogenesis of sarcoidosis, and highlight recent studies exploring potential implications of human microbiota in the pathogenesis and the clinical course of sarcoidosis.

SpotLight Proteomics-A IgG-Enrichment Phenotype Profiling Approach with Clinical Implications

Sarcoidosis is a systemic interstitial lung disease of unknown aetiology. Less invasive diagnostics are needed to decipher disease pathology and to distinguish sub-phenotypes. Here we test if SpotLight proteomics, which combines de novo MS/MS sequencing of enriched IgG and co-extracted proteins with subsequent label-free quantification of new and known peptides, can differentiate controls and sarcoidosis phenotypes (Löfgrens and non-Löfgrens syndrome, LS and nonLS). Intra-individually matched IgG enriched from serum and bronchial lavage fluid (BALF) from controls (n = 12), LS (n = 11) and nonLS (n = 12) were investigated. High-resolution mass-spectrometry SpotLight proteomics and uni- and multivariate-statistical analyses were used for data processing. Major differences were particularly observed in control-BALF versus sarcoidosis-BALF. However, interestingly, information obtained from BALF profiles was still present (but less prominent) in matched serum profiles. By using information from orthogonal partial least squares discriminant analysis (OPLS-DA) differentiating 1) sarcoidosis-BALF and control-BALF and 2) LS-BALF vs. nonLS-BALF, control-serum and sarcoidosis-serum (p = 0.0007) as well as LS-serum and nonLS-serum (p = 0.006) could be distinguished. Noteworthy, many factors prominent in identifying controls and patients were those associated with Fc-regulation, but also features from the IgG-Fab region and novel peptide variants. Differences between phenotypes were mostly IgG-specificity related. The results support the analytical utility of SpotLight proteomics which prospectively have potential to differentiate closely related phenotypes from a simple blood test.

Revised criteria of International Workshop on Ocular Sarcoidosis (IWOS) for the diagnosis of ocular sarcoidosis

AIMS

International criteria for the diagnosis of ocular sarcoidosis (OS) was established by the first International Workshop on Ocular Sarcoidosis (IWOS) and validations studies revealed certain limitations of the criteria. To overcome the limitations, revised IWOS criteria was established in an international meeting. This manuscript was aimed at reporting the revised IWOS criteria.

METHODS

A consensus workshop was carried out to discuss and revise the IWOS criteria. The workshop was held on 27 April 2017, in Nusa Dua, Bali, Indonesia. Prior to the workshop, a questionnaire proposing revised criteria and consisting of one item for differential diagnosis, seven items for ocular clinical signs, 10 items for systemic investigations and three categories of diagnostic criteria was circulated to 30 uveitis specialists. Questionnaire items with over 75% support were taken as consensus agreement; items with below 50% support were taken as consensus disagreement and items with 50%-75% support were discussed at the workshop. Of the latter items, those supported by two-thirds majority in the workshop were taken as consensus agreement.

RESULTS

The survey and subsequent workshop reached consensus agreements of the revised criteria for the diagnosis of OS as follows: (1) other causes of granulomatous uveitis must be ruled out; (2) seven intraocular clinical signs suggestive of OS; (3) eight results of systemic investigations in suspected OS and (4) three categories of diagnostic criteria depending on biopsy results and combination of intraocular signs and results of systemic investigations.

CONCLUSIONS

Revised IWOS criteria were proposed by a consensus workshop.

Epidemiology of sarcoidosis: current findings and future directions

Sarcoidosis is a granulomatous inflammatory disease with unknown etiology. Epidemiological studies have contributed greatly to our knowledge about sarcoidosis, providing critical information on the determinants and distribution of the disease. In this review, we summarize recently published findings from epidemiological studies on sarcoidosis. We review the epidemiological tools used, the incidence and prevalence of disease, mortality and cancer risk after sarcoidosis and nongenetic risk factors for sarcoidosis. Genetics studies have not been included as they deserve a separate review. Leveraging existing epidemiological data to conduct etiological studies aimed towards understanding and preventing disease is critical for future sarcoidosis research.

Sarcoid of the Upper Humerus Found Incidentally on MR Images Obtained for Work-Up of Rotator Cuff Tear Where Compromised Tissue Quality Was a Concern for Surgical Success

Sarcoidosis is an idiopathic systemic inflammatory disorder characterized histologically by noncaseating granulomas. The pathogenesis likely includes genetic, immunologic, and environmental factors. The lungs, skin, and eyes are most commonly affected. Although bone involvement is possible, sarcoidosis of the humerus is rare, with few cases reported. Furthermore, we are unaware of any reports of sarcoidosis of the upper humerus with a coexisting rotator cuff tear. We report the case of a 50-year-old female with sarcoidosis of the humerus and a coexisting tear of the supraspinatus tendon. Her medical history includes type 2 diabetes, depression, and fatigue. She had chronic shoulder pain that worsened after her dog jerked on the leash. Radiographs were grossly normal. Subsequent magnetic resonance imaging (MRI) demonstrated a possible small full-thickness rotator cuff tear. Multiple rounded lesions were also noted within the proximal humerus. A biopsy demonstrated noncaseating granulomas, confirming the diagnosis of sarcoidosis. There was concern that her sarcoid lesions would compromise bone quality, limiting options for surgical repair of her rotator cuff tear. However, it was determined that her lesion did not involve cortical bone, and surgery was performed. During surgery, the supraspinatus tendon was found to be partially torn and was treated with arthroscopic debridement and acromioplasty. An excellent result was ultimately achieved after her rheumatologist started adalimumab injections. This case demonstrates that there can be a rare incidental finding of osseous sarcoid lesions in the upper humerus where the bone might be compromised in the location of a planned rotator cuff repair.

Mycobacterium tuberculosis: An Adaptable Pathogen Associated With Multiple Human Diseases

Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB), is an extremely successful pathogen that adapts to survive within the host. During the latency phase of infection, M. tuberculosis employs a range of effector proteins to be cloud the host immune system and shapes its lifestyle to reside in granulomas, sophisticated, and organized structures of immune cells that are established by the host in response to persistent infection. While normally being restrained in immunocompetent hosts, M. tuberculosis within granulomas can cause the recrudescence of TB when host immunity is compromised. Aside from causing TB, accumulating evidence suggests that M. tuberculosis is also associated with multiple other human diseases, such as pulmonary complications, autoimmune diseases, and metabolic syndromes. Furthermore, it has been recently appreciated that M. tuberculosis infection can also reciprocally interact with the human microbiome, which has a strong link to immune balance and health. In this review, we highlight the adaptive survival of M. tuberculosis within the host and provide an overview for regulatory mechanisms underlying interactions between M. tuberculosis infection and multiple important human diseases. A better understanding of how M. tuberculosis regulates the host immune system to cause TB and reciprocally regulates other human diseases is critical for developing rational treatments to better control TB and help alleviate its associated comorbidities.

Sarcoidosis: a review for the internist

Sarcoidosis is a systemic granulomatous lung disease of unknown origin affecting people of any age, mainly young adults. The disease is extremely heterogeneous with an unpredictable clinical course. Different phenotypes have been identified: an acute syndrome can be distinguished from subacute and chronic variants. About 20% of patients are chronically progressive and may develop lung fibrosis. Sarcoidosis usually involves the lungs and thoracic lymph nodes, although the skin, eyes, bones, liver, spleen, heart, upper respiratory tract and nervous system can also be affected. No reliable indicators of clinical outcome are available, and there is no single serological biomarker with demonstrated unequivocal diagnostic and prognostic value. Diagnosis requires histological confirmation although a presumptive diagnosis may be acceptable in special conditions. This review examines the diagnostic approach to sarcoidosis involving a multidisciplinary team of specialists in which the internist has the task of identifying all pulmonary and extrapulmonary localizations of the disease and of managing complications and comorbidities.

[Sarcoidosis and uveitis : An update]

Ocular involvement in sarcoidosis is present in up to one third of patients and is frequently manifested before the underlying systemic disease has been diagnosed. With a view to the therapeutic consequences an early diagnosis of the underlying disease is advantageous. In cases of visual loss early diagnostic measures include invasive procedures, such as ultrasound-guided bronchoalveolar lavage and transbronchial biopsy, if nodular conjunctival or cutaneous manifestations which would confirm the diagnosis are not present. Sufficiently sensitive biomarkers of disease activity have not yet been identified. As elevated activity of angiotensin-converting enzyme (ACE) and lysozyme are associated with disease activity they may be supportive of but not specific for the diagnosis. Other indicators include calcemia, calciuria, augmented activity of hepatic enzymes, cutaneous anergy and hilar changes in the lungs. In patients with newly diagnosed anterior uveitis presenting with granulomatous mutton-fat corneal precipitates, snow balls and vitreous body base condensates with mild retinal periphlebitis in intermediate uveitis as well as multifocal choroiditis (creamy choroidal lesions at different stages of activity and approximately 500 µm in diameter), a diagnosis of sarcoidosis has to be considered and tuberculosis should be excluded, even in the absence of a known systemic disease. Anterior uveitis is frequently a self-limiting condition, which can be well-controlled with topical steroids. On the other hand, intermediate, posterior and panuveitis are typically associated with a chronic course and require systemic therapy to prevent severe loss of vision. If the response to systemic corticosteroids is insufficient, treatment with immunomodulatory agents and biologics is initiated at progressively earlier stages, with a view to averting permanent organ damage and frequently with a positive impact on the short and long-term outcomes, even in therapy-refractive cases.