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

The Renin-Angiotensin-Aldosterone System Regulates Sarcoidosis Granulomatous Inflammation

Rationale: Sarcoidosis is a granulomatous disorder of unclear cause notable for abnormal elevation of blood and tissue ACE1 (angiotensin converting enzyme 1) levels and activity. ACE1 regulates the renin-angiotensin-aldosterone system (RAAS), the terminal product of which is aldosterone, which selectively engages mineralocorticoid receptors to promote inflammation. Objectives: We sought to determine whether the RAAS promotes sarcoidosis granuloma formation and related inflammatory responses. Methods: Using an established ex vivo model, we first determined whether aldosterone was produced by sarcoidosis granulomas and verified the presence of CYP11B2, the enzyme required for its production. We then evaluated the effects of selective inhibitors of ACE1 (captopril), angiotensin type 1 receptor (losartan), and mineralocorticoid receptors (spironolactone, eplerenone) on granuloma formation, reflected by computer image analysis-generated granuloma area, and selected cytokines incriminated in sarcoidosis pathogenesis. Measurements and Main Results: Aldosterone was spontaneously produced by sarcoidosis peripheral blood mononuclear cells, and both intra- and extracellular levels steadily increased during granuloma formation. In parallel, peripheral blood mononuclear cells were shown to express more CYP11B2 during granuloma formation. Significant inhibition of sarcoidosis granulomas and related cytokines (TNFα, IL-1β, IFNγ, IL-10) was observed in response to pretreatments with captopril, losartan, spironolactone, or eplerenone, comparable to that of prednisone. Conclusions: The RAAS is intact in sarcoidosis granulomas and contributes significantly to early granuloma formation and to related inflammatory mediator responses, with important implications for clinical management.

Diagnostic Utility of QuantiFERON-Gold Testing in Patients with Ocular Inflammation in a Low-Endemic Tuberculosis Region

PURPOSE

To evaluate the diagnostic value of QuantiFERON Gold (QFT-G) testing for ocular inflammation in a low prevalence tuberculosis (TB) area.

DESIGN

Diagnostic utility analysis.

METHODS

A review was performed for all uveitis patients who underwent QFT-G testing at the University of Colorado Eye Center from 2009 to 2022. Records were reviewed to assess QFT-G positivity rate and to identify which patients were tested for diagnostic purposes, defined as meeting the Standardization of Uveitis Nomenclature (SUN) criteria for tubercular uveitis (TBU): anterior uveitis with iris nodules, serpiginous-like choroiditis, choroidal nodule resembling a tuberculoma, multifocal choroiditis, or occlusive retinal vasculitis.

RESULTS

A total of 388 patients with uveitis underwent QFT-G testing, of which 17 (4.38%) were positive. Only one (5.88%) patient had true TBU with anterior uveitis with iris nodules. The remaining 16 (94.1%) patients did not meet SUN criteria for TBU and were incidentally found to be QFT-G positive during laboratory work-up prior to immunosuppression. The positive predictive value was 100% when QFT-G testing was performed in patients who met SUN criteria for TBU, whereas the positive predictive value was 0% for QFT-G testing performed in patients who did not meet SUN criteria for TBU.

CONCLUSION

In low prevalence areas, the majority of QFT-G positive tests in uveitis patients are coincidental and unrelated to their uveitic disease process. The diagnostic value of a TB test is likely to be minimal unless the SUN clinical criteria for tubercular uveitis are met.

Spatial distribution of Mycobacterium tuberculosis mRNA and secreted antigens in acid-fast negative human antemortem and resected tissue

BACKGROUND

The ability to detect evidence of Mycobacterium tuberculosis (Mtb) infection within human tissues is critical to the study of Mtb physiology, tropism, and spatial distribution within TB lesions. The capacity of the widely-used Ziehl-Neelsen (ZN) staining method for identifying Mtb acid-fast bacilli (AFB) in tissue is highly variable, which can limit detection of Mtb bacilli for research and diagnostic purposes. Here, we sought to circumvent these limitations via detection of Mtb mRNA and secreted antigens in human tuberculous tissue.

METHODS

We adapted RNAscope, an RNA in situ hybridisation (RISH) technique, to detect Mtb mRNA in ante- and postmortem human TB tissues and developed a dual ZN/immunohistochemistry staining approach to identify AFB and bacilli producing antigen 85B (Ag85B).

FINDINGS

We identified Mtb mRNA within intact and disintegrating bacilli as well as extrabacillary mRNA. Mtb mRNA was distributed zonally within necrotic and non-necrotic granulomas. We also found Mtb mRNA within, and adjacent to, necrotic granulomas in ZN-negative lung tissue and in Ag85B-positive bronchiolar epithelium. Intriguingly, we observed accumulation of Mtb mRNA and Ag85B in the cytoplasm of host cells. Notably, many AFB were negative for Ag85B staining. Mtb mRNA was observed in ZN-negative antemortem lymph node biopsies.

INTERPRETATION

RNAscope and dual ZN/immunohistochemistry staining are well-suited for identifying subsets of intact Mtb and/or bacillary remnants in human tissue. RNAscope can identify Mtb mRNA in ZN-negative tissues from patients with TB and may have diagnostic potential in complex TB cases.

FUNDING

Wellcome Leap Delta Tissue Program, Wellcome Strategic Core Award, the National Institutes of Health (NIH, USA), the Mary Heersink Institute for Global Health at UAB, the UAB Heersink School of Medicine.

Infectious and non-infectious precipitants of sarcoidosis

Sarcoidosis is a chronic inflammatory disease that can affect any organ in the body. Its exact cause remains unknown, but it is believed to result from a combination of genetic and environmental factors. Some potential causes of sarcoidosis include genetics, environmental triggers, immune system dysfunction, the gut microbiome, sex, and race/ethnicity. Genetic mutations are associated with protection against disease progression or an increased susceptibility to more severe disease, while exposure to certain chemicals, bacteria, viruses, or allergens can trigger the formation of immune cell congregations (granulomas) in different organs. Dysfunction of the immune system, including autoimmune reactions, may also contribute. The gut microbiome and factors such as being female or having African American, Scandinavian, Irish, or Puerto Rican heritage are additional contributors to disease outcome. Recent research has suggested that certain drugs, such as anti-Programmed Death-1 (PD-1) and antibiotics such as tuberculosis (TB) drugs, may raise the risk of developing sarcoidosis. Hormone levels, particularly higher levels of estrogen and progesterone in women, have also been linked to an increased likelihood of sarcoidosis. The diagnosis of sarcoidosis involves a comprehensive assessment that includes medical history, physical examination, laboratory tests, and imaging studies. While there is no cure for sarcoidosis, the symptoms can often be effectively managed through various treatment options. Treatment may involve the use of medications, surgical interventions, or lifestyle changes. These disparate factors suggests that sarcoidosis has multiple positive and negative exacerbants on disease severity, some of which can be ameliorated and others which cannot.

Biomarkers in Sarcoidosis: Beginning of a New Era?

At present, no biomarker exists which is truly specific for sarcoidosis and the ones available have modest sensitivity and specificity. The clinical context should dictate the choice of biomarker(s) used to address different clinical questions such as diagnosis, monitoring disease activity or monitoring response to treatment. In the future, in addition to known serum biomarkers, it seems fruitful to further explore a possible role of imaging, exhaled air and even biopsy-related biomarkers in sarcoidosis to guide clinical management.

Ocular Sarcoidosis

Sarcoidosis frequently affects the eye and can do so in many different ways. Sarcoidosis causing uveitis can have distinctive features that facilitate identifying sarcoidosis as the cause of the uveitis. Progress is being made in elucidating ocular sarcoidosis, as for example, by transcriptomics, genetics, therapy, and imaging.

Lung microbiome: new insights into the pathogenesis of respiratory diseases

The lungs were long thought to be sterile until technical advances uncovered the presence of the lung microbial community. The microbiome of healthy lungs is mainly derived from the upper respiratory tract (URT) microbiome but also has its own characteristic flora. The selection mechanisms in the lung, including clearance by coughing, pulmonary macrophages, the oscillation of respiratory cilia, and bacterial inhibition by alveolar surfactant, keep the microbiome transient and mobile, which is different from the microbiome in other organs. The pulmonary bacteriome has been intensively studied recently, but relatively little research has focused on the mycobiome and virome. This up-to-date review retrospectively summarizes the lung microbiome's history, composition, and function. We focus on the interaction of the lung microbiome with the oropharynx and gut microbiome and emphasize the role it plays in the innate and adaptive immune responses. More importantly, we focus on multiple respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), fibrosis, bronchiectasis, and pneumonia. The impact of the lung microbiome on coronavirus disease 2019 (COVID-19) and lung cancer has also been comprehensively studied. Furthermore, by summarizing the therapeutic potential of the lung microbiome in lung diseases and examining the shortcomings of the field, we propose an outlook of the direction of lung microbiome research.

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.

Immune mechanisms of granuloma formation in sarcoidosis and tuberculosis

Sarcoidosis is a complex immune-mediated disease characterized by clusters of immune cells called granulomas. Despite major steps in understanding the cause of this disease, many questions remain. In this Review, we perform a mechanistic interrogation of the immune activities that contribute to granuloma formation in sarcoidosis and compare these processes with its closest mimic, tuberculosis, highlighting shared and divergent immune activities. We examine how Mycobacterium tuberculosis is sensed by the immune system; how the granuloma is initiated, formed, and perpetuated in tuberculosis compared with sarcoidosis; and the role of major innate and adaptive immune cells in shaping these processes. Finally, we draw these findings together around several recent high-resolution studies of the granuloma in situ that utilized the latest advances in single-cell technology combined with spatial methods to analyze plausible disease mechanisms. We conclude with an overall view of granuloma formation in sarcoidosis.

T-cell signature cytokines distinguish pulmonary sarcoidosis from pulmonary tuberculosis

Sarcoidosis is a systemic inflammatory disorder characterized by tissue infiltration due to mononuclear phagocytes and lymphocytes and associated noncaseating granuloma formation. Pulmonary sarcoidosis (PS) shares a number of clinical, radiological, and histopathological characteristics with that of pulmonary tuberculosis (PTB). Due to this, clinicians face issues in differentiating between PS and PTB in a substantial number of cases. There is a lack of any specific biomarker that can diagnose PS distinctively from PTB. We compared T-cell-based signature cytokines in patients with PS and PTB. In this study, we proposed a serum biomarker panel consisting of cytokines from cells: T helper (Th) 1 [interferon-gamma (IFN-γ); tumor necrosis factor-alpha (TNF-α)], Th9 [interleukin (IL)-9], Th17 [IL-17], and T regulatory (Treg) [IL-10; transforming growth factor-beta (TGF-β)]. We performed the principal component analysis that demonstrated that our serum cytokine panel has a significant predictive ability to differentiate PS from PTB. Our results could aid clinicians to improve the diagnostic workflow for patients with PS in TB endemic settings where the diagnosis between PS and PTB is often ambiguous.

Pulmonary miliary sarcoidosis masquerading the reactivation of tuberculosis 30 years later

Key Clinical Message

Sarcoidosis may occur after treatment with pulmonary tuberculosis and requires differential diagnosis from tuberculosis reactivation. Miliary sarcoidosis should be promptly differentiated from miliary tuberculosis associated with high mortality.

Abstract

Clinical, histological, and radiological similarities between sarcoidosis and tuberculosis render differential diagnosis challenging. The association between these two diseases has long been discussed, although the coexistence or subsequent occurrence of tuberculosis and sarcoidosis is rare. We report a case of miliary sarcoidosis that developed 30 years after tuberculous pleurisy treatment. Sarcoidosis may occur after treatment with pulmonary tuberculosis and requires differential diagnosis from tuberculosis reactivation. Although miliary sarcoidosis is uncommon, it should be promptly differentiated from miliary tuberculosis associated with high mortality. This study reignites the debate on the causal association between tuberculosis and sarcoidosis.

Cystatin C as a Potential Blood Biomarker for Sarcoidosis: A Case Report

Sarcoidosis is a multi-organ medical condition that is characterized by the formation of granulomas. We aimed to identify a correlation between each sarcoidosis blood biomarker and cystatin C (Cys-C) in sarcoidosis patients. We report a case of a 60-year-old man with sarcoidosis. The correlation between his Cys-C and each blood biomarker level and that between each blood biomarker and serum creatinine levels were determined using linear regression. Serum Cys-C correlated with each blood biomarker of sarcoidosis, while creatinine did not. These findings suggest that Cys-C is a potential blood biomarker for sarcoidosis.

Sarcoidosis rates in BCG-vaccinated and unvaccinated young adults: A natural experiment using Danish registers

OBJECTIVES

Sarcoidosis may have an infectious trigger, including Mycobacterium spp. The Bacille Calmette-Guérin (BCG) vaccine provides partial protection against tuberculosis and induces trained immunity. We examined the incidence rate (IR) of sarcoidosis in Danish individuals born during high BCG vaccine uptake (born before 1976) compared with individuals born during low BCG vaccine uptake (born in or after 1976).

METHODS

We performed a quasi-randomized registry-based incidence study using data from the Danish Civil Registration System and the Danish National Patient Registry between 1995 and 2016. We included individuals aged 25-35 years old and born between 1970 and 1981. Using Poisson regression models, we calculated the incidence rate ratio (IRR) of sarcoidosis in individuals born during low BCG vaccine uptake versus high BCG vaccine uptake, adjusting for age and calendar year (separately for men and women).

RESULTS

The IR of sarcoidosis was increased for individuals born during low BCG vaccine uptake compared with individuals born during high BCG vaccine uptake, which was largely attributed to men. The IRR of sarcoidosis for men born during low BCG vaccine uptake versus high BCG vaccine uptake was 1.22 (95% confidence interval [CI] 1.02-1.45). In women, the IRR was 1.08 (95% CI 0.88-1.31).

CONCLUSION

In this quasi-experimental study that minimizes confounding, the time period with high BCG vaccine uptake was associated with a lower incidence rate of sarcoidosis in men, with a similar effect seen in women that did not reach significance. Our findings support a potential protective effect of BCG vaccination against the development of sarcoidosis. Future interventional studies for high-risk individuals could be considered.

Sarcoidosis and Autoimmune Inflammatory Syndrome Induced by Adjuvants

Currently, sarcoidosis remains one of the diseases with unknown etiology, which significantly complicates its diagnosis and treatment. Various causes of sarcoidosis have been studied for many years. Both organic and inorganic trigger factors, provoking the development of granulomatous inflammation are considered. However, the most promising and evidence-based hypothesis is the development of sarcoidosis as an autoimmune disease, provoked by various adjuvants in genetic predisposed individuals. This concept fits into the structure of the autoimmune/inflammatory syndrome, induced by adjuvants (ASIA) that was proposed in 2011 by Professor Shoenfeld Y. In this paper, the authors reveal the presence of major and minor ASIA criteria for sarcoidosis, propose a new concept of the course of sarcoidosis within the framework of ASIA, and point out the difficulties in creating a model of the disease and the selection of therapy. It is obvious that the data obtained not only bring us closer to understanding the nature of sarcoidosis, but also potentiate new studies confirming this hypothesis by obtaining a model of the disease.

Sarcoidosis

Sarcoidosis is a disease of unknown cause characterized by granulomatous inflammation. Although the lung is almost universally involved, any organ can be affected. Complex pathogenesis and protean clinical manifestations are additional features of the disease. The diagnosis is one of exclusion, although the presence of noncaseating granulomas at disease sites is a prerequisite in most cases. The management of sarcoidosis requires a multidisciplinary approach, particularly when the heart, the brain, or the eyes are involved. The paucity of effective therapies and the lack of reliable predictors of disease behavior greatly contribute to making sarcoidosis a challenging disease to manage.

Prevalence of Positive QuantiFERON-TB Test among Sarcoid Uveitis Patients and its Clinical Implications in a Country Non-endemic for Tuberculosis

AIM

To report on the prevalence and clinical implications of positive QuantiFERON-TB (QFT) test results in the diagnostic evaluation of a cohort of consecutive sarcoid uveitis patients in France.

DESIGN

Retrospective cross-sectional study.

METHODS

This study included consecutive sarcoid uveitis patients who all underwent QFT testing.

RESULTS

A total of 234 patients were included in the study, among them 28 (12%) were QFT-positive. Previously treated tuberculosis (TB) was documented in 2 patients. QFT-positive patients were older (59 ± 16 years vs. 51 ± 18 years, p = .025) and more in proportion to suffer from chronic uveitis and panuveitis compared to QFT-negative patients. Moderate and severe visual impairment were significantly more frequent in the QFT-positive group (35.7% vs. 18.9%, p = .049 and 25.0% vs. 9.2%, p = .022, respectively).

CONCLUSION

The significant proportion of QFT-positive patients (12%) in this large series of sarcoid uveitis patients makes us suggest not to exclude the diagnosis of sarcoidosis in case of positive QFT in a low-endemic country for tuberculosis, and to manage these patients early by initiating without delay systemic steroids associated with latent tuberculosis therapy.

Sarcoid-like Granulomatosis Associated with Immune Checkpoint Inhibitors in Melanoma

We aimed to review the clinical and biological presentation of granulomatosis associated with immune-checkpoint inhibitors (ICI) in patients with melanoma and to explore its association with classical sarcoidosis as well as with cancer response to ICI. To this end, a retrospective study on 18 melanoma patients with histologically proven ICI-induced granulomatosis over a 12-year period in a single center, as well as on 67 similar cases reported in the literature, was conducted. Results indicate ICI-induced granulomatosis is an early side effect (median time to onset: 2 months). Its clinical presentation, with predominant (90%) thoracic involvement, histopathological appearance and supposed underlying biology (involving the mTOR pathway in immune cells, Th17 polarization and TReg dysfunction) are indistinguishable from those of sarcoidosis. Moreover, it appears to be associated with ICI benefit (>65% objective response rate). Evolution is generally favorable, and symptomatic steroid treatment and/or ICI discontinuation are rarely necessary. ICI-associated granulomatosis is critical to explore for several reasons. Practically, it is essential to differentiate it from cancer progression. Secondly, this “experimental” sarcoidosis brings new elements that may help to address sarcoidosis origin and pathophysiology. Its association with ICI efficacy must be confirmed on a larger scale but could have significant impacts on patient management and biomarker definition.

The Evolving Landscape of Cutaneous Sarcoidosis: Pathogenic Insight, Clinical Challenges, and New Frontiers in Therapy

Sarcoidosis is a multisystem disorder of unknown etiology characterized by accumulation of granulomas in affected tissue. Cutaneous manifestations are among the most common extrapulmonary manifestations in sarcoidosis and can lead to disfiguring disease requiring chronic therapy. In many patients, skin disease may be the first recognized manifestation of sarcoidosis, necessitating a thorough evaluation for systemic involvement. Although the precise etiology of sarcoidosis and the pathogenic mechanisms leading to granuloma formation, persistence, or resolution remain unclear, recent research has led to significant advances in our understanding of this disease. This article reviews recent advances in epidemiology, sarcoidosis clinical assessment with a focus on the dermatologist's role, disease pathogenesis, and new therapies in use and under investigation for cutaneous and systemic sarcoidosis.

Innate and Adaptive Immunity in Noninfectious Granulomatous Lung Disease

Sarcoidosis and chronic beryllium disease are noninfectious lung diseases that are characterized by the presence of noncaseating granulomatous inflammation. Chronic beryllium disease is caused by occupational exposure to beryllium containing particles, whereas the etiology of sarcoidosis is not known. Genetic susceptibility for both diseases is associated with particular MHC class II alleles, and CD4⁺ T cells are implicated in their pathogenesis. The innate immune system plays a critical role in the initiation of pathogenic CD4⁺ T cell responses as well as the transition to active lung disease and disease progression. In this review, we highlight recent insights into Ag recognition in chronic beryllium disease and sarcoidosis. In addition, we discuss the current understanding of the dynamic interactions between the innate and adaptive immune systems and their impact on disease pathogenesis.

A review of hypersensitivity methods to detect immune responses to SARS-CoV-2

The investigation of the immune response after SARS-CoV-2 infection has been the goal of many researchers worldwide. The study of humoral immune responses and in vitro T cell production after infection requires the obtaining of individualized blood samples to test the presence of antibodies or activated T cells specific for the virus. In vitro T cell studies are especially troublesome due to the need for more specialized resources often outside the daily routine of clinical laboratories. For this reason the development of a simple and objective method to achieve these T cell studies is needed. In this manuscript we reviewed the hypersensitivity reactions, the theoretical basis and the historical background of delayed type hypersensitivity (DTH) which uses the principles of use of this test in the clinical setting for the past century. In the second part of the review, we focus on COVID adaptive immune responses, to understand the differences and challenges offered by this new application of DTH to investigate immune responses elicited after infection. In the last part of the review a vision provided for the use of this test to investigate the immunogenicity elicited by the vaccines. In our opinion, the clinical guidelines of immune assessment of SARS-CoV-2-infected or vaccinated individuals should include this simple and low-cost test to measure T-cell immunity. Rationale and improved vaccination schemes could be obtained after its implementation in the routine assessment of immunity in this pandemic situation.

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.

Antifibrotic effect of Gancao Ganjiang decoction is mediated by PD-1 / TGF-β1 / IL-17A pathway in bleomycin-induced idiopathic pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Firstly prescribed in the ancient Chinese book Jingui Yaolue, Gancao Ganjiang decoction (GGD) is a traditional Chinese herbal formula that has been widely used to treat "atrophic lung disease". GGD is a popular and widely used traditional Chinese medicine. The decoction is extracted from the dried rhizomes and roots of Glycyrrhiza uralensis Fisch. and Zingiber officinale Roscoe (2:1).

AIM OF STUDY

To investigate the therapeutic effect of idiopathic pulmonary fibrosis (IPF) of GGD, a bleomycin-induced IPF murine model was used in this study.

MATERIALS AND METHODS

Mice were induced by bleomycin instillation and GGD was orally administered. Changes on mice weight were recorded during the experiment. Lung weight was recorded on days 14 and 28, and pulmonary index was calculated accordingly. Pathological evaluation, including fibrosis analysis of lung tissue, was assessed by H&E and Masson staining. The expression of PD-1, p-STAT3 and IL-17A were detected by immunohistochemistry (IHC). The expression of p-STAT3 in lung tissues of mice were detected by Western blot. The level of IL-17A in lung tissue were detected by ELISA. The expression of PD-1 in CD4+ T cells in peripheral blood of mice was detected by flow cytometry. The levels of hydroxyproline and TGF-β1 in lung tissue were detected by ELISA. The expression of E-cadherin, vimentin and α-SMA in lung tissues of mice were detected by qRT-PCR and Western blot.

RESULTS

GGD can increase body weight and reduce pulmonary index in mice with pulmonary fibrosis. As such, GGD can significantly improve the inflammatory and alleviate IPF in the lung tissue of mice. GGD treatment was capable of reducing the content of PD-1 in lung tissue as well as the expression of PD-1 in CD4+ T cells in peripheral blood. Likewise, GGD was able to reduce the content of p-STAT3, IL-17A and TGF-β1. In addition, GGD stimulation could inhibit epithelial-mesenchymal transformation (EMT) by increasing the expression of E-cadherin and reducing vimentin and α-SMA, thus reducing extracellular matrix (ECM) deposition.

CONCLUSION

Our results indicate that GGD positively affects IPF by regulating PD-1/TGF-β1/IL-17A pathway.

Cardiac sarcoidosis: from diagnosis to treatment

Sarcoidosis is a systemic granulomatous disease of unknown cause. Its clinical presentations are heterogeneous and virtually any organ system can be affected, most commonly lungs. The manifestations of cardiac sarcoidosis (CS) are heterogenous depending on the extent and location of the disease and range from asymptomatic forms to life-threatening arrhythmias as well as to progressive heart failure. Cardiac involvement is associated with a worse prognosis. The diagnosis of CS is often challenging and requires a multimodality approach based on current international recommendations. Pharmacological treatment of CS is based on administration of anti-inflammatory therapy (mainly corticosteroids), which is often combined with heart failure medication and/or antiarrhythmics. Nonpharmacological therapeutic approaches in CS cover pacemaker or defibrillator implantation, catheter ablations and heart transplantation. This review aims to summarize the current understanding of CS including its epidemiology, etiopathogenesis, clinical presentations, diagnostic approaches, and therapeutic possibilities.

CD4+ T cells in the lungs of acute sarcoidosis patients recognize an Aspergillus nidulans epitope

Löfgren’s syndrome (LS) is an acute form of sarcoidosis characterized by a genetic association with HLA-DRB1*03 (HLA-DR3) and an accumulation of CD4⁺ T cells of unknown specificity in the bronchoalveolar lavage (BAL). Here, we screened related LS-specific TCRs for antigen specificity and identified a peptide derived from NAD-dependent histone deacetylase hst4 (NDPD) of Aspergillus nidulans that stimulated these CD4⁺ T cells in an HLA-DR3–restricted manner. Using ELISPOT analysis, a greater number of IFN-γ– and IL-2–secreting T cells in the BAL of DR3⁺ LS subjects compared with DR3⁺ control subjects was observed in response to the NDPD peptide. Finally, increased IgG antibody responses to A. nidulans NDPD were detected in the serum of DR3⁺ LS subjects. Thus, our findings identify a ligand for CD4⁺ T cells derived from the lungs of LS patients and suggest a role of A. nidulans in the etiology of LS.

IL23R on myeloid cells is involved in murine pulmonary granuloma formation

PURPOSE OF THE STUDY

The involvement of the IL-23/IL23R pathway is well known in the disease pathogenesis of sarcoidosis and other inflammatory diseases. To date, the pathogenic mechanism of IL-23 is most notably described on CD4⁺ Th17 lymphocytes. However, the function of the IL23R on myeloid cells in sarcoidosis is poorly understood. Thus, the aim of the study is to investigate the role of the IL23R on myeloid cell in pulmonary granuloma formation. Methods: We generated IL23RLysMCre mice lacking the IL23R gene in myeloid cells. The importance of IL23R in myeloid cells for the development of sarcoidosis was studied in a mouse model of inflammatory lung granuloma formation through embolization of PPD from Mycobacterium bovis-coated Sepharose beads into previously PPD-immunized mice. In addition the function of IL23R on myeloid cells was studied in LPS or IFNγ stimulated BMDMs and BMDCs. The mRNA and protein expression levels of relevant cytokines were analyzed by RT-PCR (TaqMan) and ELISA. The composition of immune cells in BALF was quantified by flow cytometry and alteration in granuloma sizes were observed by H&E stained lung sections. Results: Mycobacterium Ag-elicted pulmonary granulomas tend to be smaller in IL23RLysMCre mice and NF-κB dependent Th1 cytokines in the murine lungs are reduced compared to wildtype mice. In line, we observed that IL23R-deficient bone marrow-derived macrophages show a reduced production of Th1 cytokines after LPS stimulation. Conclusion: We here for the first time demonstrate a role for IL23R on myeloid cells in pulmonary inflammation and granuloma formation. Our findings provide essential insights in the pathogenesis of inflammatory lung diseases like sarcoidosis, which might be useful for the development of novel therapeutics targeting distinct immunological pathways like IL-23/IL23R.

Immunohistochemical Detection of Propionibacterium acnes in Granulomas for Differentiating Sarcoidosis from Other Granulomatous Diseases Utilizing an Automated System with a Commercially Available PAB Antibody

Propionibacterium acnes is implicated in the pathogenesis of sarcoidosis. We investigated the usefulness of immunohistochemistry (IHC) with a commercially available P. acnes-specific monoclonal antibody (PAB antibody) for differentiating sarcoidosis from other granulomatous diseases. Formalin-fixed paraffin-embedded tissue samples from 94 sarcoidosis patients and 30 control patients with other granulomatous diseases were examined by the original manual IHC method. We also compared the detection frequency of P. acnes in sarcoid granulomas between manual and automated IHC methods. P. acnes was detected in sarcoid granulomas of samples obtained by transbronchial lung biopsy (64%), video-associated thoracic surgery (67%), endobronchial-ultrasound-guided transbronchial-needle aspiration (32%), lymph node biopsy (80%), and skin biopsy (80%) from sarcoidosis patients, but not in any non-sarcoid granulomas of the samples obtained from control patients. P. acnes outside granulomas, however, was frequently detected in both groups. The detection status of P. acnes in granulomas did not correlate with the clinical characteristics of sarcoidosis patients. The automated Leica system exhibited the best detection sensitivity (72%) and almost an identical localization for P. acnes in sarcoid granulomas compared with the manual method. IHC with a PAB antibody is useful for differentiating sarcoidosis from other granulomatous diseases by detecting P. acnes in granulomas. An automated method by the Leica system can be used in pathology laboratories for differential diagnosis of granulomas by IHC with the PAB antibody.

Epigenetics and sarcoidosis

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

Inflammatory Pathways in Sarcoidosis

Concepts regarding etiology and pathophysiology of sarcoidosis have changed remarkably within the past 5 years. Sarcoidosis is now viewed as a complex multi-causation disease related to a diverse collection of external environmental or infectious signals. It is generally accepted that the cause of sarcoidosis is unknown. Moreover, concepts of the inflammatory pathway have been modified by the realization that intrinsic genetic factors and innate immunity may modify adaptive immune responses to external triggers. With those potential regulatory pathways in mind, we will attempt to discuss the current understanding of the inflammatory response in sarcoidosis with emphasis on development of pulmonary granulomatous pathology. In that context, we will emphasize that both macrophages and T lymphocytes play key roles, with sometimes overlapping cytokine production (i.e., TNFα and IFN-γ) but also with unique mediators that influence the pathologic picture. Numerous studies have shown that in a sizable number of sarcoidosis patients, granulomas spontaneously resolve, usually within 3 years. Other sarcoidosis patients, however, may develop a chronic granulomatous disease which may subsequently lead to fibrosis. This chapter will outline our current understanding of inflammatory pathways in sarcoidosis which initiate and mediate granulomatous changes or onset of pulmonary fibrosis.

Involvement of Dendritic Cells and Th17 Cells in Induced Tertiary Lymphoid Structures in a Chronic Beryllium Disease Mouse Model

Objective

To study airway pathophysiology and the role of dendritic cells (DCs) and IL-17 receptor (IL-17R) signals in a mouse model for CBD.

Methods

Here, we present a CBD mouse model in which mice were exposed to beryllium during three weeks. We also exposed IL-17R-deficient mice and mice in which DCs were depleted.

Results

Eight weeks after the initial beryllium exposure, an inflammatory response was detected in the lungs. Mice displayed inflammation of the lower airways that included focal dense infiltrates, granuloma-like foci, and tertiary lymphoid structure (TLS) containing T cells, B cells, and germinal centers. Alveolar cell analysis showed significantly increased numbers of CD4⁺ T cells expressing IFNγ, IL-17, or both cytokines. The pathogenic role of IL-17R signals was demonstrated in IL-17R-deficient mice, which had strongly reduced lung inflammation and TLS development following beryllium exposure. In CBD mice, pulmonary DC subsets including CD103⁺ conventional DCs (cDCs), CD11b⁺ cDCs, and monocyte-derived DCs (moDCs) were also prominently increased. We used diphtheria toxin receptor-mediated targeted cell ablation to conditionally deplete DCs and found that DCs are essential for the maintenance of TLS in CBD. Furthermore, the presence of antinuclear autoantibodies in the serum of CBD mice showed that CBD had characteristics of autoimmune disease.

Conclusions

We generated a translational model of sarcoidosis driven by beryllium and show that DCs and IL-17R signals play a pathophysiological role in CBD development as well as in established CBD in vivo.

New laboratory criteria of the autoimmune inflammation in pulmonary sarcoidosis and tuberculosis

Sarcoidosis and tuberculosis have many clinical and laboratory similarities, which allowed researchers to assume the presence of common pathogenetic mechanisms in the development of both diseases. Recently, much attention has been paid to investigate the autoimmune origins in these pathologies. The aim of this study is to find out the characteristics of the autoinflammatory immune response in sarcoidosis and tuberculosis. In patients with sarcoidosis (n = 93), tuberculosis (n = 28), and in healthy donors (n = 40), the serum anti-MCV concentration was measured by ELISA, and B cell subpopulations were analyzed by flow cytometry. Based on the results obtained, the formula ([B-naïve%]\[B-memory%]) * ([B-CD38%] + [B-CD5%]) / [anti-MCV] was described. The increase in the calculated index by more than 5 units with a sensitivity of 80.00% and a specificity of 93.10% (AUC = 0.926) suggest the presence of the autoimmune component, which is more typical for sarcoidosis, rather than tuberculosis patients and may serve as a diagnostic criterion.

Phagosome-regulated mTOR signalling during sarcoidosis granuloma biogenesis

INTRODUCTION

Sarcoidosis and tuberculosis are granulomatous pulmonary diseases characterised by heightened immune reactivity to Mycobacterium tuberculosis antigens. We hypothesised that an unsupervised analysis comparing the molecular characteristics of granulomas formed in response to M. tuberculosis antigens in patients with sarcoidosis or latent tuberculosis infection (LTBI) would provide novel insights into the pathogenesis of sarcoidosis.

METHODS

A genomic analysis identified differentially expressed genes in granuloma-like cell aggregates formed by sarcoidosis (n=12) or LTBI patients (n=5) in an established in vitro human granuloma model wherein peripheral blood mononuclear cells were exposed to M. tuberculosis antigens (beads coated with purified protein derivative) and cultured for 7 days. Pathway analysis of differentially expressed genes identified canonical pathways, most notably antigen processing and presentation via phagolysosomes, as a prominent pathway in sarcoidosis granuloma formation. The phagolysosomal pathway promoted mechanistic target of rapamycin complex 1 (mTORc1)/STAT3 signal transduction. Thus, granuloma formation and related immune mediators were evaluated in the absence or presence of various pre-treatments known to prevent phagolysosome formation (chloroquine) or phagosome acidification (bafilomycin A1) or directly inhibit mTORc1 activation (rapamycin).

RESULTS

In keeping with genomic analyses indicating enhanced phagolysosomal activation and predicted mTORc1 signalling, it was determined that sarcoidosis granuloma formation and related inflammatory mediator release was dependent upon phagolysosome assembly and acidification and mTORc1/S6/STAT3 signal transduction.

CONCLUSIONS

Sarcoidosis granulomas exhibit enhanced and sustained intracellular antigen processing and presentation capacities, and related phagolysosome assembly and acidification are required to support mTORc1 signalling to promote sarcoidosis granuloma formation.

Respiratory Tract Manifestations of Inflammatory Bowel Disease

Inflammatory bowel disease can manifest in many extraintestinal organ systems. The most frequently involved extraintestinal locations include the mucocutaneous, hepatobiliary, and ocular organ systems. The respiratory tract is less commonly involved and is therefore frequently overlooked. Consequently, it is believed that involvement of the respiratory tract in patients with inflammatory bowel disease is underreported. The pathogenesis is thought to be multifactorial, involving the common embryologic origin shared by the respiratory and luminal digestive tract, molecular mimicry, and immunologic interactions leading to immune-complex deposition in affected tissue. The spectrum of manifestations of the respiratory tract related to inflammatory bowel disease is broad. It not only includes direct involvement of the respiratory tract (ie, airways, interstitium, and pleura) but also can result as a consequence of systemic involvement such as in thromboembolic events. In addition, it may also be related to other conditions that affect the respiratory tract such as sarcoidosis and alpha-1 antitrypsin deficiency. Though some conditions related to respiratory tract involvement might be subclinical, others may have life-threatening consequences. It is critical to approach patients with suspected inflammatory bowel disease-related respiratory tract involvement in concert with pulmonology, infectious diseases, and any other pertinent experts, as treatments may require a multidisciplinary overlap of measures. Therefore, it is of paramount importance for the clinician to be aware of the array of respiratory tract manifestations of patients with inflammatory bowel disease, in addition to the possible spectrum of therapeutic measures.

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.

Challenges in Cardiac and Pulmonary Sarcoidosis: JACC State-of-the-Art Review

Sarcoidosis is a complex disease with heterogeneous clinical presentations that can affect virtually any organ. Although the lung is typically the most common organ involved, combined pulmonary and cardiac sarcoidosis (CS) account for most of the morbidity and mortality associated with this disease. Pulmonary sarcoidosis can be asymptomatic or result in impairment in quality of life and end-stage, severe, and/or life-threatening disease. The latter outcome is seen almost exclusively in those with fibrotic pulmonary sarcoidosis, which accounts for 10% to 20% of pulmonary sarcoidosis patients. CS is problematic to diagnose and may cause significant morbidity and death from heart failure or ventricular arrhythmias. The diagnosis of CS usually requires surrogate cardiac imaging biomarkers, as endomyocardial biopsy has relatively low yield, even with directed electrophysiological mapping. Treatment of CS is often multifactorial, involving a combination of antigranulomatous therapy and pharmacotherapy for cardiac arrhythmias and/or heart failure in addition to device placement and cardiac transplantation.

Phase II Investigation of the Efficacy of Antimycobacterial Therapy in Chronic Pulmonary Sarcoidosis

Background

A Phase I, single-center investigation found that 8 weeks of antimycobacterial therapy improved sarcoidosis FVC. Safety and efficacy assessments have not been performed in a multicenter cohort.

Research Question

The objective of this study was to determine the safety and efficacy of antimycobacterial therapy on the physiological and immunologic end points of sarcoidosis.

Study Design and Methods

In a double-blind, placebo-controlled, multicenter investigation, patients with pulmonary sarcoidosis were randomly assigned to receive 16 weeks of concomitant levofloxacin, ethambutol, azithromycin, and rifabutin (CLEAR) or matching placebo to investigate the effect on FVC. The primary outcome was a comparison of change in percentage of predicted FVC among patients randomized to receive CLEAR or placebo in addition to their baseline immunosuppressive regimen. Secondary outcomes included 6-min walk distance (6MWD), St. George’s Respiratory Questionnaire (SGRQ) score, adverse events, and decrease in mycobacterial early secreted antigenic target of 6 kDa (ESAT-6) immune responses.

Results

The intention-to-treat analysis revealed no significant differences in change in FVC among the 49 patients randomized to receive CLEAR (1.1% decrease) compared with the 48 randomized to receive placebo (0.02% increase) (P = .64). Physiological parameters such as the change in 6MWD were likewise similar (P = .91); change in SGRQ favored placebo (–8.0 for placebo vs –1.5 for CLEAR; P = .028). The per-protocol analysis revealed no significant change in FVC at 16 weeks between CLEAR and placebo. There was no significant change in 6MWD (36.4 m vs 6.3 m; P = .24) or SGRQ (–2.3 vs –7.0; P = .14). A decline in ESAT-6 immune responses at 16 weeks was noted among CLEAR-treated patients (P = .0003) but not patients receiving placebo (P = .24).

Interpretation

Despite a significant decline in ESAT-6 immune responses, a 16-week CLEAR regimen provided no physiological benefit in FVC or 6MWD among patients with sarcoidosis.

Treatment of Sarcoidosis: A Multidisciplinary Approach

Sarcoidosis is a systemic disease of unknown etiology defined by the presence of noncaseating granulomatous inflammation that can cause organ damage and diminished quality of life. Treatment is indicated to protect organ function and decrease symptomatic burden. Current treatment options focus on interruption of granuloma formation and propagation. Clinical trials guiding evidence for treatment are lacking due to the rarity of disease, heterogeneous clinical course, and lack of prognostic biomarkers, all of which contribute to difficulty in clinical trial design and implementation. In this review, a multidisciplinary treatment approach is summarized, addressing immunuosuppressive drugs, managing complications of chronic granulomatous inflammation, and assessing treatment toxicity. Discovery of new therapies will depend on research into pathogenesis of antigen presentation and granulomatous inflammation. Future treatment approaches may also include personalized decisions based on pharmacogenomics and sarcoidosis phenotype, as well as patient-centered approaches to manage immunosuppression, symptom control, and treatment of comorbid conditions.

Key Players and Biomarkers of the Adaptive Immune System in the Pathogenesis of Sarcoidosis

Sarcoidosis is a systemic inflammatory disease characterized by development of granulomas in the affected organs. Sarcoidosis is often a diagnosis of exclusion, and traditionally used tests for sarcoidosis demonstrate low sensitivity and specificity. We propose that accuracy of diagnosis can be improved if biomarkers of altered lymphocyte populations and levels of signaling molecules involved in disease pathogenesis are measured for patterns suggestive of sarcoidosis. These distinctive biomarkers can also be used to determine disease progression, predict prognosis, and make treatment decisions. Many subsets of T lymphocytes, including CD8⁺ T-cells and regulatory T-cells, have been shown to be dysfunctional in sarcoidosis, and the predominant CD4⁺ T helper cell subset in granulomas appears to be a strong indicator of disease phenotype and outcome. Studies of altered B cell populations, B cell signaling molecules, and immune complexes in sarcoidosis patients reveal promising biomarkers as well as possible explanations of disease etiology. Furthermore, examined biomarkers raise questions about new treatment methods and sarcoidosis antigens.

Sarcoidosis is associated with lower risks of penetrating disease and colectomy in hospitalized patients with inflammatory bowel disease

Background and Aim

Inflammatory bowel disease (IBD) and sarcoidosis, primarily considered distinct entities, share commonalties in pathophysiology and clinical manifestations. This study aimed to examine the in‐hospital outcomes of patients with concurrent IBD and sarcoidosis.

Methods

The National Inpatient Sample was used to identify hospitalized adult patients with IBD and sarcoidosis from 2010 to 2014. Primary outcomes were in‐hospital mortality, rates of septic shock, acute renal failure, respiratory failure, length of stay, and total hospitalization charges. Secondary outcomes were IBD‐specific complications and surgery interventions.

Results

A total of 3995 patients with IBD and coexisting sarcoidosis (IBD/sarcoidosis), of which 2500 patients had Crohn's disease with coexisting sarcoidosis (Crohn's disease [CD]/sarcoidosis) and 1495 patients had ulcerative colitis with coexisting sarcoidosis (ulcerative colitis [UC]/sarcoidosis), were included. Patients with IBD/sarcoidosis had a lower risk of penetrating disease (adjusted odds ratio [aOR] 0.3, 95% confidence interval [CI] 0.16–0.55, P < 0.0001) and colectomy (aOR 0.48, 95% CI 0.27–0.84, P < 0.05). Subgroup analysis demonstrated lower rates of colectomy when comparing CD/sarcoidosis (P < 0.05) and UC/sarcoidosis (P = 0.0003) versus CD or UC alone. There was no difference in mortality.

Conclusion

IBD/sarcoidosis is associated with lower risks of penetrating disease and colectomy when compared to patients with IBD alone.

Catch the rainbow: Prognostic factor of sarcoidosis

Sarcoidosis is a systemic, chronic, inflammatory disease characterized by noncaseating granuloma formations. The fact that the etiopathogenesis of the disease has not been elucidated yet brings it many theories and assumptions. Being a systemic disease and ability to involve many organs and systems, it attracts the attention of physicians from different branches. In addition to lung involvement, skin, eye, heart, and locomotor system involvement is an important clinical finding. Sarcoidosis may present with very different clinical presentations, and therefore, it is one of the important "imitators" in the medical literature. I like sarcoidosis as a "rainbow," it is a disease that contains the characteristics of many diseases. Different clinical, radiological, and laboratory prognostic factors (lupus pernio, chronic uveitis, late-onset disease, chronic hypercalcemia, nephrocalcinosis, Afro-American race, progressive pulmonary sarcoidosis, radiologic Stage 4, bone involvement, neurosarcoidosis, cardiac involvement, and chronic respiratory failure) have been defined in this "rainbow." Early identification of these factors plays an important role in the determination of treatment strategies, morbidity, and mortality of the disease. In this article, clinical, genetic, laboratory, and radiological factors that determine the prognosis of sarcoidosis are discussed in light of the latest data in the literature.

Current Sarcoidosis Models and the Importance of Focusing on the Granuloma

The inability to effectively model sarcoidosis in the laboratory or in animals continues to hinder the discovery and translation of new, targeted treatments. The granuloma is the signature pathological hallmark of sarcoidosis, yet there are significant knowledge gaps that exist with regard to how granulomas form. Significant progress toward improved therapeutic and prognostic strategies in sarcoidosis hinges on tractable experimental models that recapitulate the process of granuloma formation in sarcoidosis and allow for mechanistic insights into the molecular events involved. Through its inherent representation of the complex genetics underpinning immune cell dysregulation in sarcoidosis, a recently developed in vitro human granuloma model holds promise in providing detailed mechanistic insight into sarcoidosis–specific disease regulating pathways at play during early stages of granuloma formation. The purpose of this review is to critically evaluate current sarcoidosis models and assess their potential to progress the field toward the goal of improved therapies in this disease. We conclude with the potential integrated use of preclinical models to accelerate progress toward identifying and testing new drugs and drug combinations that can be rapidly brought to clinical trials.

Models Contribution to the Understanding of Sarcoidosis Pathogenesis: "Are There Good Models of Sarcoidosis?"

Sarcoidosis is a systemic, granulomatous, and noninfectious disease of unknown etiology. The clinical heterogeneity of the disease (targeted tissue(s), course of the disease, and therapy response) supports the idea that a multiplicity of trigger antigens may be involved. The pathogenesis of sarcoidosis is not yet completely understood, although in recent years, considerable efforts were put to develop novel experimental research models of sarcoidosis. In particular, sarcoidosis patient cells were used within in vitro 3D models to study their characteristics compared to control patients. Likewise, a series of transgenic mouse models were developed to highlight the role of particular signaling pathways in granuloma formation and persistence. The purpose of this review is to put in perspective the contributions of the most recent models in the understanding of sarcoidosis.

Comparative Proteomic Analysis of Adhesion/Invasion Related Proteins in Cronobacter sakazakii Based on Data-Independent Acquisition Coupled With LC-MS/MS

Cronobacter sakazakii is foodborne pathogen that causes serious illnesses such as necrotizing enterocolitis, meningitis and septicemia in infants. However, the virulence determinants and mechanisms of pathogenicity of these species remain unclear. In this study, multilocus sequence typing (MLST) was performed on 34 C. sakazakii strains and two strains with the same sequence type (ST) but distinct adhesion/invasion capabilities were selected for identification of differentially expressed proteins using data-independent acquisition (DIA) proteomic analysis. A total of 2,203 proteins were identified and quantified. Among these proteins, 210 exhibited differential expression patterns with abundance ratios ≥3 or ≤0.33 and P values ≤0.05. Among these 210 proteins, 67 were expressed higher, and 143 were expressed lower in C. sakazakii SAKA80220 (strongly adhesive/invasive strain) compared with C. sakazakii SAKA80221 (weakly adhesive/invasive strain). Based on a detailed analysis of the differentially expressed proteins, the highly expressed genes involved in flagellar assembly, lipopolysaccharide synthesis, LuxS/AI-2, energy metabolic pathways and iron-sulfur cluster may be associated with the adhesion/invasion capability of C. sakazakii. To verify the accuracy of the proteomic results, real-time qPCR was used to analyze the expression patterns of some genes at the transcriptional level, and consistent results were observed. This study, for the first time, used DIA proteomic to investigate potential adhesion/invasion related factors as a useful reference for further studies on the pathogenic mechanism of C. sakazakii.

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.

Comparison of lung microbiota between antineutrophil cytoplasmic antibody-associated vasculitis and sarcoidosis

Microbial involvement in the pathogenesis have been suggested in both antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and sarcoidosis, both of which have lung involvement. However, exhaustive research to assess the bacteria in the lung in AAV and in sarcoidosis have not been performed. We sought to elucidate the distinct dysbiotic lung microbiota between AAV and sarcoidosis. We used 16S rRNA gene high-throughput sequencing to obtain the bacterial community composition of bronchoalveolar lavage fluid (BALF) in patients with AAV (n = 16) compared to patients with sarcoidosis (n = 21). The patients had not undergone therapy with immunosuppressive medication when their BALF was acquired. No difference was observed in α-diversity between patients with AAV and patients with sarcoidosis when using all the detected taxa. We defined the taxa of the oral cavity by using the data of oral microbiota of healthy individuals from the Human Microbiome Project (HMP). The analysis using only oral taxa made the difference in α-diversity between AAV and sarcoidosis clearer compared with those using all the detected taxa. Besides, the analysis using detected taxa except for oral taxa also made the difference in α-diversity between AAV and sarcoidosis clearer compared with those using all the detected taxa. A linear negative relationship between the α-diversity and Birmingham vasculitis activity score (BVAS) was detected in the AAV group. The observed p-value for the effect of the disease groups on the ß-diversity was small while the effect of other factors including sex and smoking status did not have small p-values. By excluding oral taxa from all the detected taxa, we found a cluster mainly consisted of sarcoidosis patients which was characterized with microbial community monopolized by Erythrobacteraceae family. Our results suggested the importance of considering the influence of oral microbiota in evaluating lung microbiota.

Sarcoidosis: Causes, Diagnosis, Clinical Features, and Treatments

Sarcoidosis is a multisystem granulomatous disease with nonspecific clinical manifestations that commonly affects the pulmonary system and other organs including the eyes, skin, liver, spleen, and lymph nodes. Sarcoidosis usually presents with persistent dry cough, eye and skin manifestations, weight loss, fatigue, night sweats, and erythema nodosum. Sarcoidosis is not influenced by sex or age, although it is more common in adults (< 50 years) of African-American or Scandinavians decent. Diagnosis can be difficult because of nonspecific symptoms and can only be verified following histopathological examination. Various factors, including infection, genetic predisposition, and environmental factors, are involved in the pathology of sarcoidosis. Exposures to insecticides, herbicides, bioaerosols, and agricultural employment are also associated with an increased risk for sarcoidosis. Due to its unknown etiology, early diagnosis and detection are difficult; however, the advent of advanced technologies, such as endobronchial ultrasound-guided biopsy, high-resolution computed tomography, magnetic resonance imaging, and 18F-fluorodeoxyglucose positron emission tomography has improved our ability to reliably diagnose this condition and accurately forecast its prognosis. This review discusses the causes and clinical features of sarcoidosis, and the improvements made in its prognosis, therapeutic management, and the recent discovery of potential biomarkers associated with the diagnostic assay used for sarcoidosis confirmation.

Adaptive Immunity in Pulmonary Sarcoidosis and Chronic Beryllium Disease

Pulmonary sarcoidosis and chronic beryllium disease (CBD) are inflammatory granulomatous lung diseases defined by the presence of non-caseating granulomas in the lung. CBD results from beryllium exposure in the workplace, while the cause of sarcoidosis remains unknown. CBD and sarcoidosis are both immune-mediated diseases that involve Th1-polarized inflammation in the lung. Beryllium exposure induces trafficking of dendritic cells to the lung in a mechanism dependent on MyD88 and IL-1α. B cells are also recruited to the lung in a MyD88 dependent manner after beryllium exposure in order to protect the lung from beryllium-induced injury. Similar to most immune-mediated diseases, disease susceptibility in CBD and sarcoidosis is driven by the expression of certain MHCII molecules, primarily HLA-DPB1 in CBD and several HLA-DRB1 alleles in sarcoidosis. One of the defining features of both CBD and sarcoidosis is an infiltration of activated CD4+ T cells in the lung. CD4+ T cells in the bronchoalveolar lavage (BAL) of CBD and sarcoidosis patients are highly Th1 polarized, and there is a significant increase in inflammatory Th1 cytokines present in the BAL fluid. In sarcoidosis, there is also a significant population of Th17 cells in the lungs that is not present in CBD. Due to persistent antigen exposure and chronic inflammation in the lung, these activated CD4+ T cells often display either an exhausted or anergic phenotype. Evidence suggests that these T cells are responding to common antigens in the lung. In CBD there is an expansion of beryllium-responsive TRBV5.1+ TCRs expressed on pathogenic CD4+ T cells derived from the BAL of CBD patients that react with endogenous human peptides derived from the plexin A protein. In an acute form of sarcoidosis, there are expansions of specific TRAV12-1/TRBV2 T cell receptors expressed on BAL CD4+ T cells, indicating that these T cells are trafficking to and expanding in the lung in response to common antigens. The specificity of these pathogenic CD4+T cells in sarcoidosis are currently unknown.

Sarcoidosis as an Autoimmune Disease

Despite the large number of performed studies, the etiology and pathogenesis of sarcoidosis still remain unknown. Most researchers allude to the possible autoimmune or immune-mediated genesis of the disease. This review attempts an integral analysis of currently available information suggesting an autoimmune genesis of sarcoidosis and is divided into four categories: the evaluation of clinical signs described both in patients with sarcoidosis and “classic” autoimmune diseases, the role of triggering factors in the development of sarcoidosis, the presence of immunogenic susceptibility in the development of the disease, and the analysis of cellular and humoral immune responses in sarcoidosis. Studying the etiology and pathogenesis of sarcoidosis will improve diagnostic procedures as well as the prognosis and patients' quality of life.