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

Sarcoidosis Associated with Enlarged Mediastinal Lymph Nodes with the Detection of Streptococcus gordonii and Cutibacterium acnes Using a Clone Library Method

A 77-year-old Japanese woman with mediastinal lymphadenopathy and uveitis was diagnosed with sarcoidosis. The bacterial flora in biopsied samples from mediastinal lymph nodes was analyzed using a clone library method with Sanger sequencing of the 16S rRNA gene, and Streptococcus gordonii (52 of 71 clones) and Cutibacterium acnes (19 of 71 clones) were detected. No previous study has conducted a bacterial floral analysis using the Sanger method for the mediastinal lymph node in sarcoidosis, making this case report the first to document the presence of S. gordonii and C. acnes in the mediastinal lymph node of a patient with sarcoidosis.

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.

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.

Offense and Defense in Granulomatous Inflammation Disease

Granulomatous inflammation (GI) diseases are a group of chronic inflammation disorders characterized by focal collections of multinucleated giant cells, epithelioid cells and macrophages, with or without necrosis. GI diseases are closely related to microbes, especially virulent intracellular bacterial infections are important factors in the progression of these diseases. They employ a range of strategies to survive the stresses imposed upon them and persist in host cells, becoming the initiator of the fighting. Microbe-host communication is essential to maintain functions of a healthy host, so defense capacity of hosts is another influence factor, which is thought to combine to determine the result of the fighting. With the development of gene research technology, many human genetic loci were identified to be involved in GI diseases susceptibility, providing more insights into and knowledge about GI diseases. The current review aims to provide an update on the most recent progress in the identification and characterization of bacteria in GI diseases in a variety of organ systems and clinical conditions, and examine the invasion and escape mechanisms of pathogens that have been demonstrated in previous studies, we also review the existing data on the predictive factors of the host, mainly on genetic findings. These strategies may improve our understanding of the mechanisms underlying GI diseases, and open new avenues for the study of the associated conditions in the future.

Multinucleated Giant Cells: Current Insights in Phenotype, Biological Activities, and Mechanism of Formation

Monocytes and macrophages are innate immune cells with diverse functions ranging from phagocytosis of microorganisms to forming a bridge with the adaptive immune system. A lesser-known attribute of macrophages is their ability to fuse with each other to form multinucleated giant cells. Based on their morphology and functional characteristics, there are in general three types of multinucleated giant cells including osteoclasts, foreign body giant cells and Langhans giant cells. Osteoclasts are bone resorbing cells and under physiological conditions they participate in bone remodeling. However, under pathological conditions such as rheumatoid arthritis and osteoporosis, osteoclasts are responsible for bone destruction and bone loss. Foreign body giant cells and Langhans giant cells appear only under pathological conditions. While foreign body giant cells are found in immune reactions against foreign material, including implants, Langhans giant cells are associated with granulomas in infectious and non-infectious diseases. The functionality and fusion mechanism of osteoclasts are being elucidated, however, our knowledge on the functions of foreign body giant cells and Langhans giant cells is limited. In this review, we describe and compare the phenotypic aspects, biological and functional activities of the three types of multinucleated giant cells. Furthermore, we provide an overview of the multinucleation process and highlight key molecules in the different phases of macrophage fusion.

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.

Challenging Mimickers in the Diagnosis of Sarcoidosis: A Case Study

Sarcoidosis is a systemic granulomatous disease of unknown cause characterized by a wide variety of presentations. Its diagnosis is based on three major criteria: a clinical presentation compatible with sarcoidosis, the presence of non-necrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease. Many conditions may mimic a sarcoid-like granulomatous reaction. These conditions include infections, neoplasms, immunodeficiencies, and drug-induced diseases. Moreover, patients with sarcoidosis are at risk of developing opportunistic infections or lymphoma. Reliably confirming the diagnosis of sarcoidosis and better identifying new events are major clinical problems in daily practice. To address such issues, we present seven emblematic cases, seen in our department, over a ten-year period along with a literature review about case reports of conditions misdiagnosed as sarcoidosis.

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.

Current perspectives on the immunopathogenesis of sarcoidosis

Sarcoidosis is an inflammatory systemic disease that commonly affects the lungs or lymph nodes but can manifest in other organs. Herein, we review the latest evidence establishing how innate and adaptive immune responses contribute to the pathogenesis and clinical course of sarcoidosis. We discuss the possible role of microbial organisms as etiologic agents in sarcoidosis and the evidence supporting sarcoidosis as an autoimmune disease. We also discuss how animal and in vitro human models have advanced our understanding of the immunopathogenesis of sarcoidosis. Finally, we discuss therapeutics for sarcoidosis and the effects on the immune system.

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.

CD163-positive macrophage infiltration predicts systemic involvement in sarcoidosis

BACKGROUND

Sarcoidosis is a chronic and systemic inflammatory disease, in which patients present with noncaseating epithelioid granulomas. Cutaneous lesions of sarcoidosis develop in 9% to 35% of all sarcoidosis patients and comprise various clinical subtypes. It usually affects multiple organs and has a variable clinical course; this is called systemic sarcoidosis (SS). However, occasionally, it only affects the skin and is then called cutaneous sarcoidosis (CS). Recent observations suggest that serum levels of soluble CD163 correlate with immune cell activity in sarcoidosis patients; however, the contribution of M1 and M2 macrophages toward disease progression remains unclear.

METHODS

We evaluated macrophage phenotypes histopathologically using skin biopsy samples obtained from patients with CS (n = 8) and SS (n = 31) and performed immunostaining with CD68, iNOS (M1 macrophages), PD-L1, and CD163 (M2 macrophages).

RESULTS

The density of CD163-positive cells in the SS group was significantly higher than that in the CS group. There was no significant correlation between the CD163 (+) cell density and serum angiotensin-converting enzyme level, serum calcium, or tuberculin reaction.

CONCLUSIONS

Immunostaining for CD163 may be a novel and useful marker to predict systemic involvement in patients with cutaneous lesions of epithelioid granulomas.