Mechanism of granuloma formation in sarcoidosis:

Serum Soluble IL-2 Receptors Are Elevated in Febrile Illnesses and Useful for Differentiating Clinically Similar Malignant Lymphomas from Kikuchi Disease: A Cross-Sectional Study

Background: The use of serum soluble interleukin 2 receptor (sIL-2R) for the diagnosis of febrile illnesses has not been examined. In this study, febrile patients were classified according to etiology and disease, and serum sIL-2R levels were evaluated. We determined whether serum sIL-2R is a useful marker for differentiating between malignant lymphoma (ML) and non-ML patients and between patients with ML and Kikuchi disease, which present similar clinical manifestations. Methods: This study was a cross-sectional study and included 344 patients with uncomplicated hemophagocytic syndrome, who had a fever of 38 °C or higher within 1 week of admission to our institution. Patient serum sIL-2R was measured, and the serum sIL-2R values are shown as median and IQR. Results: Serum sIL-2R increased above the upper reference limit in all disease groups with fever. The serum sIL-2R level in ML patients (n = 13) was 4760 (2120-6730) U/mL and significantly higher (p < 0.001) than the level of 998 (640-1625) U/mL in non-ML patients (n = 331). The serum sIL-2R level in ML patients (n = 13) was also significantly higher (p < 0.001) compared with that in patients with Kikuchi disease (n = 20; 705 (538-1091) U/mL). Conclusions: Serum sIL-2R tends to exceed the upper reference limit in patients with febrile illnesses. We conclude that the measurement of serum sIL-2R is useful for differentiating ML from non-ML and ML from Kikuchi disease.

The immunopathogenesis of sarcoidosis

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

Mimickers of Immune Checkpoint Inhibitor-induced Inflammatory Arthritis

The differential diagnosis of inflammatory arthritis as an immune-related adverse event can be challenging as patients with cancer can present with musculoskeletal symptoms that can mimic arthritis because of localized or generalized joint pain. In addition, immune checkpoint inhibitors can exacerbate joint conditions such as crystal-induced arthritis or osteoarthritis, or induce systemic disease that can affect the joints such as sarcoidosis. This distinction is important as the treatment of these conditions can be different from that of immune-related inflammatory arthritis.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.

Advance in pathogenesis of sarcoidosis: Triggers and progression

Sarcoidosis, a multisystemic immune disease, significantly impacts patients' quality of life. The complexity and diversity of its pathogenesis, coupled with limited comprehensive research, had hampered both diagnosis and treatment, resulting in an unsatisfactory prognosis for many patients. In recent years, the research had made surprising progress in the triggers of sarcoidosis (genetic inheritance, infection and environmental factors) and the abnormal regulations on immunity during the formation of granuloma. This review consolidated the latest findings on sarcoidosis research, providing a systematic exploration of advanced studies on triggers, immune-related regulatory mechanisms, and clinical applications. By synthesizing previous discoveries, we aimed to offer valuable insights for future research directions and the development of clinical diagnosis and treatment strategies.

Extra-axial cranial nerve enhancement: a pattern-based approach

Cranial nerve enhancement is a common and challenging MRI finding that requires a meticulous and systematic evaluation to identify the correct diagnosis. Literature mainly describes the various pathologies with the associated clinic-radiological characteristics, while the radiologist often needs a reverse approach that starts from the radiological findings to reach the diagnosis. Therefore, our aim is to provide a new and practical pattern-based approach to cranial nerve enhancement, which starts from the radiological findings and follows pattern-driven pipelines to navigate through multiple differential diagnoses, guiding the radiologist to reach the proper diagnosis. Firstly, we reviewed the literature and identified four patterns to categorize the main pathologies presenting with cranial nerve enhancement: unilateral linear pattern, bilateral linear pattern, unilateral thickened pattern, and bilateral thickened pattern. For each pattern, we describe the underlying pathogenic origin, and the main radiological features are displayed through high-quality MRI images and illustrative panels. A suggested MRI protocol for studying cranial nerve enhancement is also provided. In conclusion, our approach for cranial nerve enhancement aims to be an easy tool immediately applicable to clinical practice for converting challenging findings into specific pathological patterns.

Emerging Therapeutic Options for Refractory Pulmonary Sarcoidosis: The Evidence and Proposed Mechanisms of Action

Sarcoidosis is a systemic disease with heterogenous clinical phenotypes characterized by non-necrotizing granuloma formation in affected organs. Most disease either remits spontaneously or responds to corticosteroids and second-line disease-modifying therapies. These medications are associated with numerous toxicities that can significantly impact patient quality-of-life and often limit their long-term use. Additionally, a minority of patients experience chronic, progressive disease that proves refractory to standard treatments. To date, there are limited data to guide the selection of alternative third-line medications for these patients. This review will outline the pathobiological rationale behind current and emerging therapeutic agents for refractory or drug-intolerant sarcoidosis and summarize the existing clinical evidence in support of their use.

Recent Clinical Studies on the Effects of Tumor Necrosis Factor-Alpha (TNF-α) and Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) Antibody Therapies in Refractory Cutaneous Sarcoidosis: A Systematic Review

The widely accepted standard of care for chronic cutaneous sarcoidosis is corticosteroids. However, when this treatment is shown to be refractory, other interventions must be considered. In this review, we report the current progress of clinical studies on various monoclonal antibody therapies and their future potential as primary interventions for refractory cutaneous sarcoidosis. In this systematic review, clinical studies on the management of refractory cutaneous sarcoidosis were retrieved from PubMed and ScienceDirect databases. Studies were screened based on article type, publication within the last 10 years, and access to free full text. The articles selected consisted of case studies, clinical trials, and observational studies. The studies needed to focus on cases of diagnosed cutaneous sarcoidosis at the time of the study and involve adult patients resistant to corticosteroid regimens, with or without additional immunomodulators. Only interventions that included tumor necrosis factor-alpha (TNF-α) (e.g., infliximab and adalimumab) or Janus kinase/signal transducers and activators of transcription (JAK/STAT) (e.g., ruxolitinib and tofacitinib) antibody therapy were considered. Two authors independently conducted quality assessments using the Joanna Briggs Institute Critical Appraisal and NIH Study Quality Assessment tools. A total of 16 clinical studies were included in this systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram. Of the 16 cases included, 15 studies demonstrated partial to complete resolution of cutaneous lesions within a range of two weeks to 18 months from initiation of antibody therapy. Studies on anti-TNF-α intervention demonstrated the most adverse events, including two deaths and one case associated with cutaneous exacerbation. Studies on anti-JAK-STAT interventions demonstrate no adverse events after treatment; however, patient study size was limiting. Recent studies have shown promising potential for anti-TNF-α and anti-JAK-STAT inhibitors to become the mainstay interventions in refractory cutaneous sarcoidosis. Due to limited population studies, the current data on the efficacy and safety of antibody therapies have not yielded a standardized FDA-approved steroid-sparing treatment. Therefore, a need for more population studies on the effectiveness of third-line intervention in refractory cutaneous sarcoidosis is necessary.

A Hypercalcemic Enigma: A Rare Case of Bone Marrow Sarcoidosis

Sarcoidosis is a multisystem inflammatory disease involving granuloma formation. The exact etiology of the disease remains unknown. While the lungs are the most commonly involved organs in sarcoidosis, bone marrow-only involvement is quite rare. As bone marrow-only involvement can have a presentation that closely resembles multiple myeloma, a significant diagnostic dilemma can occur as the treatment for sarcoidosis is different compared to multiple myeloma. We present a case of a 62-year-old female who presented with worsening lower extremity weakness and fatigue. She was found to have new-onset hypercalcemia, normocytic anemia, and lytic bony lesions. Extensive laboratory workup for multiple myeloma was negative with bone marrow biopsy showing non-caseating granulomas, thus diagnosing the patient with sarcoidosis involving the bone marrow.

Long-term mepolizumab treatment reduces relapse rates in super-responders with eosinophilic granulomatosis with polyangiitis

BACKGROUND

The mainstay of treatment for eosinophilic granulomatosis with polyangiitis (EGPA) is systemic corticosteroid therapy; some patients also receive intravenous immunoglobulins, other immunosuppressive agents, and biologics. Mepolizumab, an anti-interleukin-5 monoclonal antibody, induces remission and decreases the daily corticosteroid dose; however, the clinical efficacy of mepolizumab in EGPA and the prognosis with long-term treatment with this drug are unknown.

METHODS

Seventy-one EGPA patients were treated at Hiratsuka City Hospital, Japan, between April 2018 and March 2022. We administered mepolizumab for a mean of 2.8 ± 1.7 years to 43 patients in whom remission could not be induced by conventional treatment. After excluding 18 patients who had received mepolizumab for less than 3 years, we classified 15 patients into a "super-responder group" (the daily dose of corticosteroids or other immunosuppressant could be decreased, or the interval between IVIG treatments could be prolonged) and 10 patients into a "responder group" (neither of these changes was achievable). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and other immunosuppressants, Birmingham Vasculitis Activity Score (BVAS), and relapse frequency before and after mepolizumab initiation were determined.

RESULTS

Blood eosinophil count at diagnosis and the lowest serum IgG level before mepolizumab treatment were significantly higher in super-responders than in responders (p < 0.05). In super-responders, the prednisolone dose at last visit on mepolizumab treatment was lower than that before treatment (p < 0.01) and lower than that at last visit in the responders (p < 0.01). In both groups, peripheral blood eosinophil numbers and BVAS were lower after starting mepolizumab than before (p < 0.01). BVAS before mepolizumab (p < 0.05) and at last visit (p < 0.01) were lower in super-responders than in responders. Relapse rates every year after the start of mepolizumab were lower in super-responders than in responder groups (p < 0.01). In super-responders, relapse rates were lower during the 3 years following mepolizumab initiation (p < 0.01) and at last visit (p < 0.01) were significantly lower than after 1 year of treatment.

CONCLUSION

Mepolizumab treatment of super-responders sustainably reduced the relapse rate.

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.

Hypoxemic Respiratory Failure Due to Alveolar Pulmonary Sarcoidosis Following COVID-19 Infection

Pulmonary sarcoidosis is typically recognized as an interstitial lung disease with an infrequent occurrence of alveolar filling or acinar pattern. This rare form of alveolar sarcoidosis is known to have a rapid progression. Several case reports showed the development/worsening of sarcoidosis after COVID-19 infection. We present a case of a 60-year-old male with chronic hypoxic respiratory failure since having COVID-19 disease followed by gradual progression in symptoms, who had atypical sarcoid-like alveolar opacities on radiography, two prior negative bronchoscopies, transbronchial biopsy and BAL, and third bronchoscopic transbronchial biopsy suggestive of findings of poorly formed granulomas with high suspicion of alveolar sarcoidosis after ruling out other comparative possibilities, and later having a drastic improvement with sarcoidosis management. Our patient's worsening symptoms after COVID-19 infection suggest impaired immunoregulation role of the infection in developing the disease process.

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.

Functional link between sarcoidosis-associated gene variants and quantitative levels of bronchoalveolar lavage fluid cell types

Background

Sarcoidosis is an inflammatory disease that affects multiple organs. Cell analysis from bronchoalveolar lavage fluid (BALF) is a valuable tool in the diagnostic workup and differential diagnosis of sarcoidosis. Besides the expansion of lymphocyte expression-specific receptor segments (Vα2.3 and Vβ22) in some patients with certain HLA types, the relation between sarcoidosis susceptibility and BAL cell populations' quantitative levels is not well-understood.

Methods

Quantitative levels defined by cell concentrations of BAL cells and CD4⁺/CD8⁺ ratio were evaluated together with genetic variants associated with sarcoidosis in 692 patients with extensive clinical data. Genetic variants associated with clinical phenotypes, Löfgren's syndrome (LS) and non-Löfgren's syndrome (non-LS), were examined separately. An association test via linear regression using an additive model adjusted for sex, age, and correlated cell type was applied. To infer the biological function of genetic associations, enrichment analysis of expression quantitative trait (eQTLs) across publicly available eQTL databases was conducted.

Results

Multiple genetic variants associated with sarcoidosis were significantly associated with quantitative levels of BAL cells. Specifically, LS genetic variants, mainly from the HLA locus, were associated with quantitative levels of BAL macrophages, lymphocytes, CD3⁺ cells, CD4⁺ cells, CD8⁺ cells, CD4⁺/CD8⁺ ratio, neutrophils, basophils, and eosinophils. Non-LS genetic variants were associated with quantitative levels of BAL macrophages, CD8⁺ cells, basophils, and eosinophils. eQTL enrichment revealed an influence of sarcoidosis-associated SNPs and regulation of gene expression in the lung, blood, and immune cells.

Conclusion

Genetic variants associated with sarcoidosis are likely to modulate quantitative levels of BAL cell types and may regulate gene expression in immune cell populations. Thus, the role of sarcoidosis-associated gene-variants may be to influence cellular phenotypes underlying the disease immunopathology.

An expert overview of pulmonary fibrosis in sarcoidosis

INTRODUCTION

Advanced pulmonary sarcoidosis refers to phenotypes of pulmonary sarcoidosis that often lead to significant loss of lung function, respiratory failure, or death. Around 20% of patients with sarcoidosis may progress to this state which is mainly driven by advanced pulmonary fibrosis. Advanced fibrosis often presents with associated complications of sarcoidosis including infections, bronchiectasis, and pulmonary hypertension.

AREAS COVERED

This article will focus on the pathogenesis, natural history of disease, diagnosis, and potential treatment options of pulmonary fibrosis in sarcoidosis. In the expert opinion section, we will discuss the prognosis and management of patients with significant disease.

EXPERT OPINION

While some patients with pulmonary sarcoidosis remain stable or improve with anti-inflammatory therapies, others develop pulmonary fibrosis and further complications. Although advanced pulmonary fibrosis is the leading cause of death in sarcoidosis, there are no evidence-based guidelines for the management of fibrotic sarcoidosis. Current recommendations are based on expert consensus and often include multidisciplinary discussions with experts in sarcoidosis, pulmonary hypertension, and lung transplantation to facilitate care for such complex patients. Current works evaluating treatments include the use of antifibrotic therapies for treatment in advanced pulmonary sarcoidosis.

Granulomatous inflammation in inborn errors of immunity

Granulomas have been defined as inflammatory infiltrates formed by recruitment of macrophages and T cells. The three-dimensional spherical structure typically consists of a central core of tissue resident macrophages which may merge into multinucleated giant cells surrounded by T cells at the periphery. Granulomas may be triggered by infectious and non-infectious antigens. Cutaneous and visceral granulomas are common in inborn errors of immunity (IEI), particularly among patients with chronic granulomatous disease (CGD), combined immunodeficiency (CID), and common variable immunodeficiency (CVID). The estimated prevalence of granulomas in IEI ranges from 1%-4%. Infectious agents causing granulomas such Mycobacteria and Coccidioides presenting atypically may be 'sentinel' presentations for possible underlying immunodeficiency. Deep sequencing of granulomas in IEI has revealed non-classical antigens such as wild-type and RA27/3 vaccine-strain Rubella virus. Granulomas in IEI are associated with significant morbidity and mortality. The heterogeneity of granuloma presentation in IEI presents challenges for mechanistic approaches to treatment. In this review, we discuss the main infectious triggers for granulomas in IEI and the major forms of IEI presenting with 'idiopathic' non-infectious granulomas. We also discuss models to study granulomatous inflammation and the impact of deep-sequencing technology while searching for infectious triggers of granulomatous inflammation. We summarize the overarching goals of management and highlight the therapeutic options reported for specific granuloma presentations in IEI.

Multiorgan sarcoidosis as a diabetes insipidus mask

Summary

Sarcoidosis is an inflammatory, multisystem disease with an undetermined etiology. The presence of noncaseating granulomas in involved organs is a characteristic pathomorphological feature. Sarcoidosis, like a chameleon, can mimic different medical conditions. Although the lungs are most commonly involved, extrapulmonary manifestations can influence any system. The clinical course of the disease may differ. Immediate initiation of glucocorticosteroid therapy is important when critical organs are impaired. A case of a patient with sarcoidosis whose first clinical symptoms were related to diabetes insipidus (DI) was presented. The diagnosis of multiple organ sarcoidosis was delayed because of an adequate response to treatment with vasopressin. The multidisciplinary diagnostic approach validated the involvement of the pituitary gland, lungs, lymph nodes, bones, and subcutaneous tissue. The presented case emphasizes the critical importance of the multifaceted differential diagnosis of patients with DI.

Learning points

Sarcoidosis usually affects the lung but can also be a multisystemic disease. The assessment of the extension of sarcoidosis remains complex. A multidisciplinary approach must identify all-organ involvement and initiate appropriate sarcoidosis treatment. Diabetes insipidus (DI) can be the first symptom of a systemic granulomatous disorder. In the differential diagnosis of DI, a comprehensive assessment of rare causes of endocrine disorders, including extrapulmonary sarcoidosis, should be considered.

The Onset of Sarcoidosis After COVID-19 Vaccination Revealed by the 18 F-FDG PET

ABSTRACT

Sarcoidosis is a heterogeneous multisystem disease characterized by noncaseating granulomas. We presented 18 F-FDG PET/CT findings of sarcoidosis in a previously healthy 43-year-old man who presented intermittent cough after the third dose of COVID-19 vaccination. 18 F-FDG PET/CT showed high uptake of one solitary nodule in the right middle lobe, mediastinal lymph nodes, bilateral hila, and multiple nodules under the right pleura, mimicking the malignancy. Nevertheless, the biopsy confirmed distinct noncaseating granulomas. This case emphasizes the onset of sarcoidosis revealed by 18 F-FDG PET/CT after COVID-19 vaccination.

Transcriptional and Immune Landscape of Cardiac Sarcoidosis

BACKGROUND

Cardiac involvement is an important determinant of mortality among sarcoidosis patients. Although granulomatous inflammation is a hallmark finding in cardiac sarcoidosis, the precise immune cell populations that comprise the granuloma remain unresolved. Furthermore, it is unclear how the cellular and transcriptomic landscape of cardiac sarcoidosis differs from other inflammatory heart diseases.

METHODS

We leveraged spatial transcriptomics (GeoMx digital spatial profiler) and single-nucleus RNA sequencing to elucidate the cellular and transcriptional landscape of cardiac sarcoidosis. Using GeoMX digital spatial profiler technology, we compared the transcriptomal profile of CD68⁺ rich immune cell infiltrates in human cardiac sarcoidosis, giant cell myocarditis, and lymphocytic myocarditis. We performed single-nucleus RNA sequencing of human cardiac sarcoidosis to identify immune cell types and examined their transcriptomic landscape and regulation. Using multichannel immunofluorescence staining, we validated immune cell populations identified by single-nucleus RNA sequencing, determined their spatial relationship, and devised an immunostaining approach to distinguish cardiac sarcoidosis from other inflammatory heart diseases.

RESULTS

Despite overlapping histological features, spatial transcriptomics identified transcriptional signatures and associated pathways that robustly differentiated cardiac sarcoidosis from giant cell myocarditis and lymphocytic myocarditis. Single-nucleus RNA sequencing revealed the presence of diverse populations of myeloid cells in cardiac sarcoidosis with distinct molecular features. We identified GPNMB (transmembrane glycoprotein NMB) as a novel marker of multinucleated giant cells and predicted that the MITF (microphthalmia-associated transcription factor) family of transcription factors regulated this cell type. We also detected additional macrophage populations in cardiac sarcoidosis including HLA-DR (human leukocyte antigen-DR)⁺ macrophages, SYTL3 (synaptotagmin-like protein 3)⁺ macrophages and CD163⁺ resident macrophages. HLA-DR⁺ macrophages were found immediately adjacent to GPMMB⁺ giant cells, a distinct feature compared with other inflammatory cardiac diseases. SYTL3⁺ macrophages were located scattered throughout the granuloma and CD163⁺ macrophages, CD1c⁺ dendritic cells, nonclassical monocytes, and T cells were located at the periphery and outside of the granuloma. Finally, we demonstrate mTOR (mammalian target of rapamycin) pathway activation is associated with proliferation and is selectively found in HLA-DR⁺ and SYLT3⁺ macrophages.

CONCLUSIONS

In this study, we identified diverse populations of immune cells with distinct molecular signatures that comprise the sarcoid granuloma. These findings provide new insights into the pathology of cardiac sarcoidosis and highlight opportunities to improve diagnostic testing.

Sarcoidosis: Progression to the chronic stage and pathogenic based treatment (narrative review)

Many factors confirm the autoimmune nature of sarcoidosis and help in determining the strategy of patient management and treatment initiation. However, the causes and the mechanisms of disease progression that result in fibrosis and insufficiency of the affected organ remain unclear. This narrative review aims to analyse the mechanisms and biomarkers of sarcoidosis progression, as well as the pathogenetic basis of sarcoidosis therapy. The following characteristics of progressive chronic sarcoidosis were revealed: the disease develops in patients with a genetic predisposition (SNP in genes GREM1, CARD15, TGF-β3, HLA-DQB1^*06:02, HLA-DRB1^*07/14/15), which contributes either the decreased ability of antigen elimination or autoimmune inflammation. Various prognostic biomarkers of disease progression (decreased levels of neopterin, elastase, sIL-2R, chitotriosidase, glycoprotein Krebs von den Lungen, Th17 cell count, reduced quantity of TNF-α in peripheral blood or bronchoalveolar lavage fluid) have been described and can potentially be used to determine the group of patients who will benefit from the use of corticosteroids/cytostatic drugs/biologics.

Pharmacological Inhibition of Chitotriosidase (CHIT1) as a Novel Therapeutic Approach for Sarcoidosis

Introduction

Methods

Results

Conclusion

Diagnostic value of elevated serum carbohydrate antigen 125 level in sarcoidosis

BACKGROUND

Sarcoidosis is a multisystem disorder with unknown etiology, and it predominantly affects the lungs and intrathoracic lymph nodes. For patients with atypical clinical manifestations, the diagnosis of sarcoidosis is difficult and specific biomarkers may play an important role in assisting diagnosis. Previous research has demonstrated a correlation between sarcoidosis and increased carbohydrate antigen 125 (CA125), but remains a lack of large cohort studies to validate this observation.

AIM

To compare serum CA125 levels in sarcoidosis patients and healthy controls, and explore whether CA125 can be used as a biomarker for the diagnosis of sarcoidosis.

METHODS

In this study, the serum CA125 levels were measured by enzyme-linked immunosorbent assay in 108 consecutive sarcoidosis patients between June 2016 and December 2020 (31 males, 77 females; age at diagnosis 49.69 ± 9.10 years) and 112 healthy subjects. Data on the C-reactive protein, erythrocyte sedimentation rate, and angiotensin-converting enzyme were also collected. The association of serum CA125 levels with clinical, radiological, and respiratory functional characteristics was analyzed between patient groups with CA125 ≤ 35 U/mL or CA125 > 35 U/mL.

RESULTS

We found that serum CA125 levels were higher in sarcoidosis patients compared to healthy controls (median: 44.78 vs 19.11 U/mL, P < 0.001). The area under the receiver operator characteristic was 0.9833 (95%CI: 0.9717-0.9949), and the best cutoff point was 32.33 U/mL. The elevated serum CA125 was notably associated with the percentage of predicted forced vital capacity (FVC%) and neutrophil-to-lymphocyte ratio (P = 0.043 and P = 0.038, respectively) in sarcoidosis patients. Multivariate analysis revealed that FVC% was a statistically notable predictor of elevated serum CA125 (P = 0.029). Also, our research revealed that compared to patients with Stage I of radiology classification, patients with Stage II and III showed a higher concentration of serum CA125 (46.16 ± 8.32 vs 41.00 ± 6.04 U/mL, P = 0.005, and 47.92 ± 10.10 vs 41.00 ± 6.04 U/mL, P = 0.002, respectively).

CONCLUSION

Serum CA125 was highly increased in sarcoidosis patients and showed high efficiency for noninvasive diagnosis of the disease. In addition, abnormally elevated serum CA125 was correlated with pulmonary function and radiological Scadding’s classification of sarcoidosis.

Relevance of Medullary Vein Sign in Neurosarcoidosis

Background: Central nervous system involvement is uncommon in patients with sarcoidosis. It remains a diagnostic challenge for clinicians, as there is a broad differential diagnosis that matches the presenting neurological signs. Often, the imaging findings also overlap with other disease entities. One understudied finding in patients with neurosarcoidosis is the presence of medullary vein engorgement on SWI imaging, termed the “medullary vein sign”, which has been postulated to be a specific sign for neurosarcoidosis. This study aims to provide an understanding of the diagnostic potential of the medullary vein sign. Methods: Thirty-two patients who presented with neurologic signs concerning for possible neurosarcoidosis were analyzed retrospectively for the presence of the medullary vein sign. Results: Out of these cases, 7 cases of definitive neurosarcoidosis cases were found based on other imaging signs, biopsy and CSF analysis; the remaining were classified into groups as possible (16), probable (5) and (4) cases of other infectious meningoencephalitis including 2 cases of autoimmune encephalitis. Seven patients among all of these cases were found to have the medullary vein sign on imaging, with five cases with confirmed and two cases from possible neurosarcoidosis. The sensitivity of the medullary vein sign in this study was 71.4%, and the specificity was 92.3%. Discussion: The benefits of improving diagnostic criteria for neurosarcoidosis include more rapid diagnosis leading to more prompt treatment, less exposure to potentially harmful antibiotics or antifungals, and less long-term neurological effects. Our results support that the medullary vein sign will potentially fill in the diagnostic gaps that have challenged the timely diagnosis of neurosarcoidosis. Conclusions: Our findings support that the medullary vein sign has a high specificity and should be included in the diagnostic criteria for neurosarcoidosis.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Sarcoid Uveitis: An Intriguing Challenger

The purpose of our work is to describe the actual knowledge concerning etiopathogenesis, clinical manifestations, diagnostic procedures, complications and therapy of ocular sarcoidosis (OS). The study is based on a recent literature review and on the experience of our tertiary referral center. Data were retrospectively analyzed from the electronic medical records of 235 patients (461 eyes) suffering from a biopsy-proven ocular sarcoidosis. Middle-aged females presenting bilateral ocular involvement are mainly affected; eye involvement at onset is present in one-third of subjects. Uveitis subtype presentation ranges widely among different studies: panuveitis and multiple chorioretinal granulomas, retinal segmental vasculitis, intermediate uveitis and vitreitis, anterior uveitis with granulomatous mutton-fat keratic precipitates, iris nodules, and synechiae are the main ocular features. The most important complications are cataract, glaucoma, cystoid macular edema (CME), and epiretinal membrane. Therapy is based on the disease localization and the severity of systemic or ocular involvement. Local, intravitreal, or systemic steroids are the mainstay of treatment; refractory or partially responsive disease has to be treated with conventional and biologic immunosuppressants. In conclusion, we summarize the current knowledge and assessment of ophthalmological inflammatory manifestations (mainly uveitis) of OS, which permit an early diagnostic assay and a prompt treatment.

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.

COVID-19-induced pulmonary sarcoid: A case report and review of the literature

Background

The COVID-19 pandemic has resulted in dramatic loss of life worldwide, but as the large number of acutely ill patients subsides, the emerging group of “COVID-19 long-haulers” present a clinical challenge. Studies have shown that many of these patients suffer long-term pulmonary disease related to residual fibrosis. Prior studies have shown that while many patients have non-specific findings of fibrotic-like changes, others develop specific patterns of interstitial lung disease.

Case report

Here, we present the first case of a patient developing pulmonary sarcoidosis one year after critical illness from COVID-19. He developed numerous non-necrotizing and well-formed granulomas in mediastinal lymph nodes and pulmonary nodules, compatible radiographically and pathologically with sarcoid.

Conclusions

While the pathophysiology of sarcoid is incompletely understood, inflammation is mediated through the dysregulation of a number of different cytokines (IFNγ, IL-2, IL-12, IL-17, IL-22). This case provides valuable clues for better understanding of the shared pathophysiology of cytokine dysregulation seen in COVID-19 and other interstitial lung diseases such as sarcoidosis.

BALF and BLOOD NK- cells in different stages of pulmonary sarcoidosis

Background and objective:

Data on natural killer (NK)- and natural killer T (NKT)- like cells in the immunopathogenesis of sarcoidosis remain limited. The aim was to assess NK- and NKT-like cells across different stages in bronchoalveolar lavage (BALF) versus peripheral blood (PB) in comparison to controls.

Methods:

Forty four patients (32 women and 12 men, mean age 46.6±14.4 years) with biopsy-proven sarcoidosis and 10 healthy individuals (6 women, 4 men mean age 52.6±19.1 years) were submitted to BALF. Total cells and cell differentials were counted, while CD45+, CD3+, CD4+, CD8+, CD19+, CD3-CD16/56 (NK cells) and CD3+CD16/56+ (NKT-like cells) were determined by dual flow cytometry in BALF and PB.

Results:

A significantly lower percentage of both NK and NKT-like cells was observed in BALF of controls and sarcoid patients (SP) compared to PB. Both BALF NK and NKT-cell counts were significantly higher in SP than in controls (NK: p=0.046, NKT-like: p=0.012) In addition BALF NK cell percentage differed among sarcoidosis stages (p=0.005). In PB NK-cell count was lower in sarcoidosis patients but the difference did not reach statistical significance. Also, in sarcoid patients’ BALF NK-cell percentage negatively correlated with lymphocyte percentage (r=-0.962, p<0.001).

Conclusions:

The increased count of BALF NK and NKT-like cells in sarcoidosis compared to controls along with the increase of NK cells with stage progression are in line with a growing number of investigations suggesting the involvement of NK- and NKT-like cells 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.

Renal involvement in sarcoidosis: histological patterns and prognosis, an Italian survey

Background

Granulomatous interstitial nephritis in sarcoidosis (sGIN) is generally clinically silent, but in <1% causes acute kidney injury (AKI).

Methods

This Italian multicentric retrospective study included 39 sarcoidosis-patients with renal involvement at renal biopsy: 31 sGIN-AKI, 5 with other patterns (No-sGIN-AKI), 3 with nephrotic proteinuria. We investigate the predictive value of clinical features, laboratory, radiological parameters and histological patterns regarding steroid response. Primary endpoint: incident chronic kidney disease (CKD) beyond the 1°follow-up (FU) year; secondary endpoint: response at 1°line steroid therapy; combined endpoint: the association of initial steroid response and outcome at the end of FU.

Results

Complete recovery in all 5 No-sGIN-AKI-patients, only in 45% (13/29) sGIN-AKI-patients (p=0.046) (one lost in follow-up, for another not available renal function after steroids). Nobody had not response. Primary endpoint of 22 sGIN-AKI subjects: 65% (13/20) starting with normal renal function developed CKD (2/22 had basal CKD; median FU 77 months, 15-300). Combined endpoint: 29% (6/21) had complete recovery and final normal renal function (one with renal relapse), 48% (10/21) had partial recovery and final CKD (3 with renal relapse, of whom one with basal CKD) (p=0.024). Acute onset and hypercalcaemia were associated to milder AKI and better recovery than subacute onset and patients without hypercalcaemia, women had better endpoints than men. Giant cells, severe interstitial infiltrate and interstitial fibrosis seemed negative predictors in terms of endpoints.

Conclusions

sGIN-AKI-patients with no complete recovery at 1°line steroid should be treated with other immunosuppressive to avoid CKD, in particular if males with subacute onset and III stage-not hypercalcaemic AKI.

Pediatric sarcoidosis with diagnostic and therapeutical insights

PURPOSE OF REVIEW

Sarcoidosis is a chronic granulomatous disorder involving multiple systems and organs of undefined etiology. Although most of the morbidity relies upon lung disease, the function of several systems and organs can be affected. The natural history of lung disease consists of pulmonary involvement. An exaggerated and abnormal inflammatory response accompanies this aspect. There are noncaseating confluent epithelioid granulomas and, potentially, a progressive airway obstruction ab externo. As the disease is multisystemic, there is an increased likelihood of complications that may be serious and even fatal.

RECENT FINDINGS

The American Thoracic Society (ATS) Core Curriculum updates clinicians annually in adult and pediatric lung disease, critical medical care, and sleep medicine. In late 2020, the ATS targeted sarcoidosis. Also, in 2019, the French Sarcoidosis Group thoroughly revised the literature on pediatric sarcoidosis. Currently, staging is based on chest radiograph findings, and the most commonly used system is the Scadding classification, which has been applied to both children and adults alike. Treatment may consist of oral or pulsed intravenous corticosteroids, but it should be implemented in union with a rheumatologist, as there are no randomized controlled studies in children.

SUMMARY

Sarcoidosis is rare in childhood. Diagnosis is complex and relies on multiple diagnostic modalities with both staging and therapy progressively mirroring the sarcoidosis, which affects adults. In the majority of patients, spontaneous resolution will occur and observation is justified above treatment. Nevertheless, in case treatment is needed corticosteroids remain the mainstay of the treatment in some pediatric patients. Relapses are not uncommon and a long-term follow-up is essential.

Antimalarial drugs-are they beneficial in rheumatic and viral diseases?-considerations in COVID-19 pandemic

The majority of the medical fraternity is continuously involved in finding new therapeutic schemes, including antimalarial medications (AMDs), which can be useful in combating the 2019-nCoV: coronavirus disease (COVID-19). For many decades, AMDs have been widely used in the treatment of malaria and various other anti-inflammatory diseases, particularly to treat autoimmune disorders of the connective tissue. The review comprises in vitro and in vivo studies, original studies, clinical trials, and consensus reports for the analysis, which were available in medical databases (e.g., PubMed). This manuscript summarizes the current knowledge about chloroquine (CQ)/hydroxychloroquine (HCQ) and shows the difference between their use, activity, recommendation, doses, and adverse effects on two groups of patients: those with rheumatic and viral diseases (including COVID-19). In the case of connective tissue disorders, AMDs are prescribed for a prolonged duration in small doses, and their effect is observed after few weeks, whereas in the case of viral infections, they are prescribed in larger doses for a short duration to achieve a quick saturation effect. In rheumatic diseases, AMDs are well tolerated, and their side effects are rare. However, in some viral diseases, the effect of AMDs is questionable or not so noticeable as suggested during the initial prognosis. They are mainly used as an additive therapy to antiviral drugs, but recent studies have shown that AMDs can diminish the efficacy of some antiviral drugs and may cause respiratory, kidney, liver, and cardiac complications.

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.

Ichthyosiform sarcoidosis: Report of a case and comprehensive review of the literature

Sarcoidosis is a disease that can affect a multitude of organs and manifest as cutaneous disease. Cutaneous manifestations of sarcoidosis vary widely in morphology, earning the nickname of "great imitator," and the diagnosis often requires clinicopathologic correlation and additional laboratory and radiographic workup. We present the case of a 42-year-old African American woman with ichthyosiform sarcoidosis on the bilateral lower extremities. As one of the rarest specific variants of cutaneous sarcoidosis, ichthyosiform is understudied and has been primarily documented in case reports and series. We undertake a comprehensive review of the literature to identify key clinicopathologic features including the characterization of sites of cutaneous and systemic involvement, as well as typical histopathological findings. Lower extremities were the most involved body site (85.7%). Extracutaneous organ involvement centered around pulmonary (65.7%), lymph node (57.1%), and ocular (31.4%) involvement. Of the histopathological features reported, hyperkeratosis (51.4%) and diminished stratum granulosum (62.9%) were most frequently reported in conjunction with dermal granulomas (100%). We hope that these findings will serve to aid clinicopathological correlation and accurate diagnosis of ichthyosiform sarcoidosis.

Lung and liver sarcoidosis-like reaction induced by tocilizumab

A drug-induced sarcoidosis-like reaction is a systemic granulomatous reaction indistinguishable from sarcoidosis and occurring in temporal relationship with a drug initiation. In this article, we report a patient who developed lung and liver granulomatous lesions following tocilizumab initiation for a giant cell arteritis. Infectious, toxic, neoplastic and inflammatory differential diagnoses were ruled out and lesions regressed after treatment cessation, leading to the diagnosis of tocilizumab induced sarcoidosis-like reaction. We review the 6 cases reported so far and emphasize the value of a prompt diagnosis. Finally, we discuss the potential pathophysiological mechanisms underlying this rare reaction, which could help to better understand the pathophysiology of sarcoidosis.

Clinical Features of Patients with Active Eosinophilic Granulomatosis with Polyangiitis Successfully Treated with Mepolizumab

BACKGROUND

In some patients with eosinophilic granulomatosis with polyangiitis (EGPA), remission cannot be induced, despite treatment with corticosteroids and immunosuppressants. We evaluated the clinical features of patients with EGPA in whom mepolizumab was effective.

METHODS

There were 59 EGPA patients treated at Hiratsuka City Hospital, Japan, between April 2018 and September 2020, and 30 of them received mepolizumab. Twenty (66.7%) experienced a "marked effect" (the daily dose of corticosteroid or immunosuppressant could be decreased, or the interval between intravenous immunoglobulin (IVIG) treatments could be prolonged) and 10 (33.3%) experienced a "weak effect" (these measures were not achieved). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and immunosuppressants, and the interval between IVIG treatments at diagnosis and before and after mepolizumab initiation were determined.

RESULTS

Eosinophil numbers at diagnosis were significantly higher in the marked-effect group than in the weak-effect group (p < 0.05) but not before mepolizumab initiation or at the last visit. Birmingham Vasculitis Activity Scores (BVASs) before mepolizumab initiation (p < 0.05) and at last visit (p < 0.01), and frequency of relapse before treatment initiation (p < 0.05) were significantly higher, and the serum IgG level before mepolizumab treatment was significantly lower in the weak-effect group than in the marked-effect group. The weak-effect group received higher doses of corticosteroids, even if the corticosteroid dose could be reduced for a while after mepolizumab initiation.

CONCLUSION

High peripheral blood eosinophil numbers at EGPA diagnosis were suggestive of a positive clinical response to mepolizumab.

Relationship to Deployment on Sarcoidosis Staging and Severity in Military Personnel

INTRODUCTION

Ongoing studies are investigating the potential link between deployment to Operation Iraqi Freedom and Operation Enduring Freedom and relationship to increases in pulmonary disease. While increases in certain diseases such as asthma and airway hyperreactivity are well established, data on other chronic pulmonary diseases such as sarcoidosis have not been defined.

MATERIAL AND METHODS

A retrospective chart review was conducted of all active duty military personnel diagnosed with sarcoidosis from 2005 to 2010. Deployment dates and locations were obtained through the Armed Forces Health Surveillance Branch. Electronic medical records were reviewed to determine the following parameters: dates of diagnosis, temporal relationship of diagnosis and deployment, symptoms (pre- and/or post-deployment), spirometry, diffusing capacity, radiographic staging, and treatment course. Pulmonary sarcoidosis incidence rates were estimated using International Classification of Diseases (ICD-9) coded medical encounter data from the Defense Medical Surveillance System and compared between Army and nonArmy personnel, as well as between ever-deployed and never-deployed personnel.

RESULTS

A cohort of 478 Army soldiers was identified with sarcoidosis based on ICD-9 codes and individual review of the medical records. The cohort was 80% male. 38.7% of soldiers with sarcoidosis never deployed. 11.7% were diagnosed prior to deployment, and 50.2% were diagnosed postdeployment. The diagnosis of sarcoidosis was established with a tissue diagnosis in 68% of the deployed cohort. Overall differences in spirometry were not identified. Obstructed spirometry was similar in all deployment groups (never, pre, and post) at 9.2%, 15.8% and 8.7%, respectively. Restrictive patterns based on total lung capacity (<70%) were similar at 9.2%, 12.5%, and 11.0%, respectively. Radiographic staging showed a similar distribution in the populations with the never/pre versus postdeployment groups having Stage 0 = 2.3 versus 3.5%, Stage I = 43.8 versus 41.6%, Stage II = 33.1 versus 41.0%, Stage III = 15.1 versus 12.1%, and Stage IV = 2.2 versus 1.7%, respectively. During 2005-2010, the estimated incidence rate of pulmonary sarcoidosis was low among active duty Army personnel (16.5 cases/100,000 person-years), and no trend in annual rates was observed, p = 0.89. Based on overall Department of Defense medical data, estimated pulmonary sarcoidosis rates were lower among ever-deployed personnel, relative to nondeployed personnel.

CONCLUSION

Based on this analysis of Army sarcoidosis patients, there was no difference in the rates of sarcoidosis diagnosis in deployed and nondeployed soldiers. Spirometry values, total lung capacity, and radiographic staging did not show significant differences between deployment groups.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.

Sarcoidosis manifesting during treatment with secukinumab for psoriatic arthritis

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

Uveitis as an Open Window to Systemic Inflammatory Diseases

Spondyloarthritis (Spa), Behçet's disease (BD) and sarcoidosis are major systemic inflammatory diseases worldwide. They are all multisystem pathologies and share a possible ocular involvement, especially uveitis. We hereby describe selected cases who were referred by ophthalmologists to our internal medicine department for unexplained uveitis. Physical examination and/or the use of laboratory and imaging investigations allowed to make a diagnosis of a systemic inflammatory disease in a large proportion of patients. In our tertiary referral center, 75 patients have been diagnosed with Spa (n = 20), BD (n = 9), or sarcoidosis (n = 46) in the last two years. There was a significant delay in the diagnosis of Spa-associated uveitis. Screening strategies using Human Leukocyte Antigen (HLA)-B27 determination and sacroiliac magnetic resonance imaging in patients suffering from chronic low back pain and/or psoriasis helped in the diagnosis. BD's uveitis affects young people from both sexes and all origins and usually presents with panuveitis and retinal vasculitis. The high proportion of sarcoidosis in our population is explained by the use of chest computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography CT that helped to identify smaller hilar or mediastinal involvement and allowed to further investigate those patients, especially in the elderly. Our results confirm how in these sight- and potentially life-threatening diseases a prompt diagnosis is mandatory and benefits from a multidisciplinary approach.

Serum Metabolomic Profiling of Patients with Non-Infectious Uveitis

The activities of various metabolic pathways can influence the pathogeneses of autoimmune diseases, and intrinsic metabolites can potentially be used to diagnose diseases. However, the metabolomic analysis of patients with uveitis has not yet been conducted. Here, we profiled the serum metabolomes of patients with three major forms of uveitis (Behҫet's disease (BD), sarcoidosis, and Vogt-Koyanagi-Harada disease (VKH)) to identify potential biomarkers. This study included 19 BD, 20 sarcoidosis, and 15 VKH patients alongside 16 healthy control subjects. The metabolite concentrations in their sera were quantified using liquid chromatography with time-of-flight mass spectrometry. The discriminative abilities of quantified metabolites were evaluated by four comparisons: control vs. three diseases, and each disease vs. the other two diseases (such as sarcoidosis vs. BD + VKH). Among 78 quantified metabolites, 24 kinds of metabolites showed significant differences in these comparisons. Four multiple logistic regression models were developed and validated. The area under the receiver operating characteristic (ROC) curve (AUC) in the model to discriminate disease groups from control was 0.72. The AUC of the other models to discriminate sarcoidosis, BD, and VKH from the other two diseases were 0.84, 0.83, and 0.73, respectively. This study provides potential diagnostic abilities of sarcoidosis, BD, and VKH using routinely available serum samples that can be collected with minimal invasiveness.

A case of granulomatous myositis in a patient with rheumatoid arthritis receiving anti-TNF-α treatment

A 66-year old woman with a 14-year history of rheumatoid arthritis (RA) and uveitis was admitted to our department for evaluation of a mass in the left neck. Fourteen months prior to this admission the patient was started on golimumab. Serum creatine kinase (CK) level was elevated and myositis-specific and -associated antibodies were negative. Manual muscle test showed weakness in the neck flexor, sternocleidomastoid and deltoid muscles. Magnetic resonance imaging (MRI) of the neck, erector muscle of spine, breech, thigh and lower thigh demonstrated high-intensity lesions in the muscles in short-tau inversion recovery images. Electromyography in the right deltoid detected fibrillation potentials. Muscle biopsy from the left neck mass showed granulomatous myositis. Muscle weakness improved and CK levels normalized after discontinuation of golimumab. We report a case of granulomatous myositis under anti-TNF-α treatment for RA.

Classical Examples of the Concept of the ASIA Syndrome

Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) was first introduced in 2011 by Shoenfeld et al. and encompasses a cluster of related immune mediated diseases, which develop among genetically prone individuals as a result of adjuvant agent exposure. Since the recognition of ASIA syndrome, more than 4400 documented cases have been reported so far, illustrated by heterogeneous clinical manifestations and severity. In this review, five enigmatic conditions, including sarcoidosis, Sjögren's syndrome, undifferentiated connective tissue disease, silicone implant incompatibility syndrome (SIIS), and immune-related adverse events (irAEs), are defined as classical examples of ASIA. Certainly, these disorders have been described after an adjuvant stimulus (silicone implantation, drugs, infections, metals, vaccines, etc.) among genetically predisposed individuals (mainly the HLA-DRB1 and PTPN22 gene), which induce an hyperstimulation of the immune system resulting in the production of autoantibodies, eventually leading to the development of autoimmune diseases. Circulating autonomic autoantibodies in the sera of patients with silicone breast implants, as well as anatomopathological aspects of small fiber neuropathy in their skin biopsies have been recently described. To our knowledge, these novel insights serve as a common explanation to the non-specific clinical manifestations reported in patients with ASIA, leading to the redefinition of the ASIA syndrome diagnostic criteria.

T-bet Expression in Peripheral Th17.0 Cells Is Associated With Pulmonary Function Changes in Sarcoidosis

Background: Interferon-gamma (IFN-γ) is a key mediator of sarcoidosis-related granulomatous inflammation. Previous findings of IFN-γ-producing Th17 cells in bronchoalveolar lavage fluid from sarcoidosis patients invokes the transition of Th17.0 cells to Th17.1 cells in the disease's pathogenesis. Since the T-bet transcription factor is crucial for this transition, the goal of this study was to determine if T-bet expression in Th17.0 cells reflects the extent of granulomatous inflammation in sarcoidosis patients as assessed by clinical outcomes.

Methods: Using a case-control study design, we identified two groups of sarcoidosis subjects (total N = 43) with pulmonary function tests (PFTs) that either (1) changed (increased or decreased) longitudinally or (2) were stable. We used flow cytometry to measure the transcription factors T-bet and RORγt in Th1, Th17.0, and Th17.1 cell subsets defined by CCR6, CCR4 and CXCR3 in blood samples. We compared the percentages of T-bet⁺ cells in RORγt⁺Th17.0 cells (defined as CCR6⁺CCR4⁺CXCR3⁻) based on subjects' PFT group. We also assessed the relationship between the direction of change in PFTs with the changes in %T-bet⁺ frequencies using mixed effects modeling.

Results: We found that T-bet expression in subjects' RORγt⁺Th17.0 cells varied based on clinical outcome. The T-bet⁺ percentage of RORγt⁺Th17.0 cells was higher in the cases (subject group with PFT changes) as compared to controls (stable group) (27 vs. 16%, p = 0.0040). In comparisons before and after subjects' PFT changes, the T-bet⁺ frequency of RORγt⁺Th17.0 cells increased or decreased in the opposite direction of the PFT change. The percentage of these T-bet⁺ cells was also higher in those with greater numbers of involved organs. Serum levels of interferon-γ-induced chemokines, CXCL9, CXCL10, and CXCL11, and whole blood gene expression of IFN-γ-related genes including GBP1, TAP1, and JAK2 were independently positively associated with the T-bet⁺ frequencies of RORγt⁺Th17.0 cells.

Conclusions: These data suggest that expression of T-bet in Th17.0 cells could reflect the extent of granulomatous inflammation in sarcoidosis patients because they represent a transition state leading to the Th17.1 cell phenotype. These findings indicate that Th17 plasticity may be part of the disease paradigm.

Biomarkers in the Diagnosis and Prognosis of Sarcoidosis: Current Use and Future Prospects

Sarcoidosis is a heterogeneous disease in terms of presentation, duration, and severity. Due to this heterogeneity, it is difficult to align treatment decisions. Biomarkers have proved to be useful for the diagnosis and prognosis of many diseases, and over the years, many biomarkers have been proposed to facilitate diagnosis, prognosis, and treatment decisions. Unfortunately, the ideal biomarker for sarcoidosis has not yet been discovered. The most commonly used biomarkers are serum and bronchoalveolar lavage biomarkers, but these lack the necessary specificity and sensitivity. In sarcoidosis, therefore, a combination of these biomarkers is often used to establish a proper diagnosis or detect possible progression. Other potential biomarkers include imaging tools and cell signaling pathways. Fluor-18-deoxyglucose positron emission tomography and high-resolution computed tomography have been proven to be more sensitive for the diagnosis and prognosis of both pulmonary and cardiac sarcoidosis than the serum biomarkers ACE and sIL-2R. There is an upcoming role for exploration of signaling pathways in sarcoidosis pathogenesis. The JAK/STAT and mTOR pathways in particular have been investigated because of their role in granuloma formation. The activation of these signaling pathways also proved to be a specific biomarker for the prognosis of sarcoidosis. Furthermore, both imaging and cell signaling biomarkers also enable patients who might benefit from a particular type of treatment to be distinguished from those who will not. In conclusion, the diagnostic and prognostic path of sarcoidosis involves many different types of existing and new biomarker. Research addressing biomarkers and disease pathology is ongoing in order to find the ideal sensitive and specific biomarker for this disease.

Cutaneous Sarcoidosis

Sarcoidosis is a chronic, multisystem, inflammatory disorder of unknown etiology that is characterized by noncaseating granulomas that impair normal organ functioning. Sarcoidosis predominantly affects the lungs, but the skin is often cited as the second most frequently involved organ. Cutaneous manifestations of sarcoidosis are highly variable and ongoing research seeks to better understand the relationship between clinical morphology and disease prognosis. Skin findings in patients with sarcoidosis can be "specific," in which sarcoidal granulomas infiltrate the skin, or they can represent a "nonspecific" reactive inflammatory process, as is seen in calcinosis cutis and erythema nodosum. Cutaneous sarcoidosis can be the initial presenting sign or develop later in the course of the disease. In some patients, the skin will be the most involved and impactful organ system and will drive therapy. In other cases, the skin will be an incidental or minor finding, but may be easily accessible for biopsy to confirm the diagnosis. There are many potential therapies for sarcoidosis, though no one therapy is universally effective.

A 43-Year-Old Woman With Hoarseness of Voice and Chest Pressure

CASE PRESENTATION

A 43-year-old woman with a medical history of cervical cancer treated with curative hysterectomy 12 years earlier developed progressive dyspnea, chest discomfort, and hoarse voice over a 7-month period. The patient never smoked and had no exposure history. Imaging at an outside hospital showed a mediastinal mass with hilar adenopathy (Fig 1A), which was biopsied via endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and revealed noncaseating granulomas with surrounding rims of lymphocytes (Fig 1B). The patient was given the diagnosis of sarcoidosis and started on prednisone 60 mg daily. She had no improvement in symptoms after 3 months of therapy and therefore presented for a second opinion.

Refractory Sarcoidosis: A Review

Sarcoidosis is a multi-system disease of unknown etiology characterized by granuloma formation in various organs (especially lung and mediastinohilar lymph nodes). In more than half of patients, the disease resolves spontaneously. When indicated, it usually responds to corticosteroids, the first-line treatment, but some patients may not respond or tolerate them. An absence of treatment response is rare and urges for verifying the absence of a diagnosis error, the good adherence of the treatment, the presence of active lesions susceptible to respond since fibrotic lesions are irreversible. That is when second-line treatments, immunosuppressants (methotrexate, leflunomide, azathioprine, mycophenolate mofetil, hydroxychloroquine), should be considered. Methotrexate is the only first-line immunosuppressant validated by a randomized controlled trial. Refractory sarcoidosis is not yet a well-defined condition, but it remains a real challenge for the physicians. Herein, we considered refractory sarcoidosis as a disease in which second-line treatments are not sufficient to achieve satisfying disease control or satisfying corticosteroids tapering. Tumor necrosis alpha inhibitors, third-line treatments, have been validated through randomized controlled trials. There are currently no guidelines or recommendations regarding refractory sarcoidosis. Moreover, criteria defining non-response to treatment need to be clearly specified. The delay to achieve response to organ involvement and drugs also should be defined. In the past ten years, the efficacy of several immunosuppressants beforehand used in other autoimmune or inflammatory diseases was reported in refractory cases series. Among them, anti-CD20 antibodies (rituximab), repository corticotrophin injection, and anti-JAK therapy anti-interleukin-6 receptor monoclonal antibody (tocilizumab) were the main reported. Unfortunately, no clinical trial is available to validate their use in the case of sarcoidosis. Currently, other immunosuppressants such as JAK inhibitors are on trial to assess their efficacy in sarcoidosis. In this review, we propose to summarize the state of the art regarding the use of immunosuppressants and their management in the case of refractory or multidrug-resistant sarcoidosis.