Tofacitinib Treatment and Molecular Analysis of Cutaneous Sarcoidosis

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.

A double-blind, placebo-controlled, randomized withdrawal trial of sarilumab for the treatment of glucocorticoid-dependent sarcoidosis

OBJECTIVES

Effective steroid-sparing therapies for the treatment of sarcoidosis are lacking; IL-6 antagonists may reduce sarcoidosis disease activity. This study assessed the safety and efficacy of the IL-6 receptor antagonist, sarilumab, in subjects with glucocorticoid-dependent sarcoidosis.

METHODS

This phase II, double-blind, placebo-controlled, randomized withdrawal trial enrolled 15 subjects with biopsy-proven sarcoidosis at Stanford University from November 2019 to September 2022. In period 1, subjects were treated with open-label s.c. sarilumab 200 mg every 2 weeks for 16 weeks, with predefined tapering of prednisone. Subjects who completed period 1 without a sarcoidosis flare entered period 2 and were randomized to continue sarilumab or to receive matching placebo for 12 weeks. The end points included flare-free survival, as well as changes in pulmonary function tests, chest imaging, patient-reported outcomes, and laboratory values.

RESULTS

Fifteen subjects were enrolled in the study (median age 57 years, 80% male, 73.3% White), and 10 subjects successfully completed period 1. During period 1, 4 of the 15 subjects (26.7%) discontinued due to worsening of their sarcoidosis, and CT chest imaging worsened in 5 of the 15 subjects (35.7%). During period 2, 0 of 2 subjects in the sarilumab group and 1 of 8 subjects (12.5%) in the placebo group had a flare. Treatment with sarilumab 200 mg was generally well tolerated in subjects with sarcoidosis.

CONCLUSION

In this double-blind, placebo-controlled, randomized withdrawal trial, a meaningful signal of improvement in subjects with sarcoidosis treated with sarilumab was not observed. Given the small numbers in this study, no definitive conclusions can be drawn.

TRIAL REGISTRATION

ClinicalTrials.gov, http://clinicaltrials.gov, NCT04008069.

Treatment of Cerebral Histiocytosis With Low Dose of Cobimetinib: A Report of 2 Cases

OBJECTIVES

Histiocytic disorders are pathologic expansions of myeloid cells in multiple organs, including the CNS. They share activation of the MAP kinase pathway due to either BRAFV600E variant or other variants in the RAS-RAF-MEK-ERK pathway. The rarity and heterogeneity of the disease only enable therapy through pathophysiologic considerations.

METHODS

We present 2 histiocytosis cases without BRAF sequence variants that affect the CNS, one with Erdheim-Chester disease and the other with an unspecified histiocytosis, and their diagnostic and therapeutic challenges.

RESULTS

In both cases, comprehensive analysis of the RAS-RAF-MEK-ERK signaling pathway secured the diagnosis. Treatment with the MEK inhibitor cobimetinib brought the disease to a complete halt. However, side effects such as thrombosis and serous macular edema made it necessary to reduce cobimetinib dosage. Low-dose cobimetinib maintenance medication was successful in preventing recurrence of histiocytic disease.

DISCUSSION

CNS involvement of histiocytic disorders can lead to detrimental neurologic symptoms. MEK inhibitors are effective treatment options for some of these patients. Since side effects are common, according to our cases we propose a low-dose treatment of 20 mg per day to balance treatment effects with side effects.

CLASSIFICATION OF EVIDENCE

This case report provides Class IV evidence. This is a single observational study without controls.

Aberrant Lipid Metabolism in Macrophages Is Associated with Granuloma Formation in Sarcoidosis

Rationale: Chronic sarcoidosis is a complex granulomatous disease with limited treatment options that can progress over time. Understanding the molecular pathways contributing to disease would aid in new therapeutic development. Objectives: To understand whether macrophages from patients with nonresolving chronic sarcoidosis are predisposed to macrophage aggregation and granuloma formation and whether modulation of the underlying molecular pathways influence sarcoidosis granuloma formation. Methods: Macrophages were cultivated in vitro from isolated peripheral blood CD14+ monocytes and evaluated for spontaneous aggregation. Transcriptomics analyses and phenotypic and drug inhibitory experiments were performed on these monocyte-derived macrophages. Human skin biopsies from patients with sarcoidosis and a myeloid Tsc2-specific sarcoidosis mouse model were analyzed for validatory experiments. Measurements and Main Results: Monocyte-derived macrophages from patients with chronic sarcoidosis spontaneously formed extensive granulomas in vitro compared with healthy control participants. Transcriptomic analyses separated healthy and sarcoidosis macrophages and identified an enrichment in lipid metabolic processes. In vitro patient granulomas, sarcoidosis mouse model granulomas, and those directly analyzed from lesional patient skin expressed an aberrant lipid metabolism profile and contained increased neutral lipids. Conversely, a combination of statins and cholesterol-reducing agents reduced granuloma formation both in vitro and in vivo in a sarcoidosis mouse model. Conclusions: Together, our findings show that altered lipid metabolism in sarcoidosis macrophages is associated with its predisposition to granuloma formation and suggest cholesterol-reducing therapies as a treatment option in patients.

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.

[Therapeutic Pathways in Sarcoidosis. A Position Paper of the German Society of Respiratory Medicine (DGP)]

The present recommendations on the therapy of sarcoidosis of the German Respiratory Society (DGP) was written in 2023 as a German-language supplement and update of the international guidelines of the European Respiratory Society (ERS) from 2021. It contains 5 PICO questions (Patients, Intervention, Comparison, Outcomes) agreed in the consensus process, which are explained in the background text of the four articles: Confirmation of diagnosis and monitoring of the disease under therapy, general therapy recommendations, therapy of cutaneous sarcoidosis, therapy of cardiac sarcoidosis.

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.

Anti-inflammatory Therapy for Sarcoidosis

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

Cutaneous Sarcoidosis

Sarcoidosis is a multisystem disease that most commonly affects the lungs, lymphatic system, eyes, and skin but any organ may be involved. Cutaneous sarcoidosis most commonly presents as pink-red to red-brown papules and plaques that commonly affect the head and neck. With the skin being readily accessible for evaluation and biopsy, when sarcoidosis is suspected, dermatologic evaluation may be helpful for establishing a definitive diagnosis. Treatment strategy depends on the severity and distribution of skin lesions and should incorporate patient preference and treatment considerations for other organs that may be involved.

STAT expression and TFH1 cells in CVID granulomatosis and sarcoidosis: immunological and histopathological comparisons

Granulomatous disease is a serious complication of common variable immunodeficiency (CVID-GD) that occurs in 8-22% of these patients and can mimic sarcoidosis, with which it shares certain clinical, biological, and radiological features. However, few studies to date have compared the two pathologies immunologically and histologically. Therefore, we analyzed the immunological-histological findings for different tissue samples from ten patients with CVID-GD and compared them to those of biopsy-proven sarcoidosis. Specifically, we wanted to know whether or not the signaling abnormalities observed in sarcoidosis granulomas are also present in CVID-GD. Morphological differences were found between CVID-GD histology and classical sarcoidosis: mainly, the former's notable lymphoid hyperplasia associated with granulomas not observed in the latter. All CVID-GD involved organs contained several follicular helper-T (TFH) cells within the granulomatosis, while those cells were inconstantly and more weakly expressed in sarcoidosis. Moreover, CVID and sarcoidosis granulomas expressed the phosphorylated-signal transducer and activator of transcription (pSTAT)1 and pSTAT3 factors, regardless of the organ studied and without any significant difference between entities. Our results suggest that the macrophage-activation mechanism in CVID resembles that of sarcoidosis, thereby suggesting that Janus kinase (JAK)-STAT-pathway blockade might be useful in currently difficult-to-treat CVID-GD.

Topical Ruxolitinib in the Treatment of Necrobiosis Lipoidica: A Prospective, Open-Label Study

Necrobiosis lipoidica (NL) is a rare granulomatous disease. There are few effective treatments for NL. We sought to investigate the efficacy and safety of the Jak1/2 inhibitor, ruxolitnib, in the treatment of NL and identify the biomarkers associated with the disease and treatment response. We conducted an open-label, phase 2 study of ruxolitinib in 12 patients with NL. We performed transcriptomic analysis of tissue samples before and after treatment. At week 12, the mean NL lesion score decreased by 58.2% (SD = 28.7%, P = .003). Transcriptomic analysis demonstrated enrichment of type I and type II IFN pathways in baseline disease. Weighted gene coexpression network analysis demonstrated post-treatment changes in IFN pathways with key hub genes IFNG and signal transducer and activator of transcription 1 gene STAT1. Limitations include small sample size and a study group limited to patients with <10% body surface area. In conclusion, ruxolitinib is an effective treatment for NL and targets the key pathogenic mediators of the disease.

Efficacy and safety of mTOR inhibition in cutaneous sarcoidosis: a single-centre trial

BACKGROUND

Sarcoidosis is an inflammatory condition that can affect various organs and tissues, causing the formation of granulomas and subsequent functional impairment. The origin of sarcoidosis remains unknown and there are few treatment options. Mechanistic target of rapamycin (mTOR) activation is commonly seen in granulomas of patients across different tissues and has been shown to induce sarcoidosis-like granulomas in a mouse model. This study aimed to examine the efficacy and safety of the mTOR inhibitor sirolimus as a treatment for cutaneous sarcoidosis.

METHODS

We did a single-centre, randomised study treating patients with persistent and glucocorticoid-refractory cutaneous sarcoidosis with sirolimus at the Vienna General Hospital, Medical University of Vienna (Vienna, Austria). We recruited participants who had persistent, active, and histologically proven cutaneous sarcoidosis. We used an n-of-1 crossover design in a placebo-controlled, double-blind topical treatment period and a subsequent single-arm systemic treatment phase for 4 months in the same participants. Participants initially received either 0·1% topical sirolimus in Vaseline or placebo (Vaseline alone), twice daily. After a washout period, all participants were subsequently administered a 6 mg loading dose followed by 2 mg sirolimus solution orally once daily, aiming to achieve serum concentrations of 6 ng/mL. The primary endpoint was change in the Cutaneous Sarcoidosis Activity and Morphology Index (CSAMI) after topical or systemic treatment. All participants were included in the safety analyses, and patients having completed the respective treatment period (topical treatment or systemic treatment) were included in the primary analyses. Adverse events were assessed at each study visit by clinicians and were categorised according to their correlation with the study drug, severity, seriousness, and expectedness. This study is registered with EudraCT (2017-004930-27) and is now closed.

FINDINGS

16 participants with persistent cutaneous sarcoidosis were enrolled in the study between Sept 3, 2019, and June 15, 2021. Six (37%) of 16 participants were men, ten (63%) were women, and 15 (94%) were White. The median age of participants was 54 years (IQR 48-58). 14 participants were randomly assigned in the topical phase and 2 entered the systemic treatment phase directly. Daily topical treatment did not improve cutaneous lesions (effect estimate -1·213 [95% CI -2·505 to 0·079], p=0·066). Systemic treatment targeting trough serum concentrations of 6 ng/mL resulted in clinical and histological improvement of skin lesions in seven (70%) of ten participants (median -7·0 [95% CI -16·5 to -3·0], p=0·018). Various morphologies of cutaneous sarcoidosis, including papular, nodular, plaque, scar, and tattoo-associated sarcoidosis, responded to systemic sirolimus therapy with a long-lasting effect for more than 1 year after treatment had been stopped. There were no serious adverse events and no deaths.

INTERPRETATION

Short-term treatment with systemic sirolimus might be an effective and safe treatment option for patients with persistent glucocorticoid-refractory sarcoidosis with a long-lasting disease-modulating effect. The effect of sirolimus in granulomatous inflammation should be investigated further in large, multi-centre, randomised clinical trials.

FUNDING

Vienna Science and Technology Fund, Austrian Science Fund.

Neurosarcoidosis

Sarcoidosis affects the nervous system in 5% of cases. 60% of cases involve the cranial and peripheral nerves, the remainder the central nervous system, in which a leptomeningitis, a pachymeningitis and a vasculitis may arise. Stroke and cerebral haemorrhage may occur, and certain infections in the brain are more likely with sarcoidosis. Patients respond well to treatment but oftentimes with residual neurological impairments which may be severe. A greater understanding of the disease and the need for early treatment and use of biological therapies have improved treatment outcome in recent times.

Janus-kinase inhibitors in dermatology: A review of their use in psoriasis, vitiligo, systemic lupus erythematosus, hidradenitis suppurativa, dermatomyositis, lichen planus, lichen planopilaris, sarcoidosis and graft-versus-host disease

Recent studies on molecular pathways have elucidated novel therapeutic approaches in inflammatory and autoimmune skin disorders. Specifically, the dysregulation of the Janus kinase signal transducer and activator of transcription (JAK-STAT) cascade plays a central role in the pathogenesis of many skin conditions. JAK inhibitors, with their ability to selectively target immune responses, are potential treatment options. Using the National Library of Medicine, we provide a comprehensive review of the use of United States Food and Drug Administration (FDA)-approved and emerging JAK or tyrosine kinase 2 (TYK2) inhibitors in a wide range of dermatologic conditions, including psoriasis, vitiligo, systemic lupus erythematosus, hidradenitis suppurativa, dermatomyositis, lichen planus, lichen planopilaris, sarcoidosis and graft-versus-host disease. In patients with psoriasis, oral deucravacitinib (TYK2 inhibitor) has been approved as a once-daily therapy with demonstrated superiority and efficacy over apremilast and placebo and tolerable safety profiles. In patients with vitiligo, topical ruxolitinib (JAK1 inhibitor) is approved as a twice-daily treatment for repigmentation. The efficacy of several other JAK inhibitors has also been demonstrated in several clinical trials and case studies for systemic lupus erythematosus, hidradenitis suppurativa, dermatomyositis, lichen planus, lichen planopilaris, sarcoidosis and graft-versus-host disease. Further investigations with long-term clinical trials are necessary to confirm their utility in treatment and safety for these diseases.

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.

Activation of the pentose phosphate pathway in macrophages is crucial for granuloma formation in sarcoidosis

Sarcoidosis is a disease of unknown etiology in which granulomas form throughout the body and is typically treated with glucocorticoids, but there are no approved steroid-sparing alternatives. Here, we investigated the mechanism of granuloma formation using single-cell RNA-Seq in sarcoidosis patients. We observed that the percentages of triggering receptor expressed on myeloid cells 2-positive (TREM2-positive) macrophages expressing angiotensin-converting enzyme (ACE) and lysozyme, diagnostic makers of sarcoidosis, were increased in cutaneous sarcoidosis granulomas. Macrophages in the sarcoidosis lesion were hypermetabolic, especially in the pentose phosphate pathway (PPP). Expression of the PPP enzymes, such as fructose-1,6-bisphosphatase 1 (FBP1), was elevated in both systemic granuloma lesions and serum of sarcoidosis patients. Granuloma formation was attenuated by the PPP inhibitors in in vitro giant cell and in vivo murine granuloma models. These results suggest that the PPP may be a promising target for developing therapeutics for sarcoidosis.

Spatial Transcriptomics Reveals Signatures of Histopathological Changes in Muscular Sarcoidosis

Sarcoidosis is a multisystemic disease characterized by non-caseating granuloma infiltrating various organs. The form with symptomatic muscular involvement is called muscular sarcoidosis. The impact of immune cells composing the granuloma on the skeletal muscle is misunderstood. Here, we investigated the granuloma-skeletal muscle interactions through spatial transcriptomics on two patients affected by muscular sarcoidosis. Five major transcriptomic clusters corresponding to perigranuloma, granuloma, and three successive muscle tissue areas (proximal, intermediate, and distal) around the granuloma were identified. Analyses revealed upregulated pathways in the granuloma corresponding to the activation of T-lymphocytes and monocytes/macrophages cytokines, the upregulation of extracellular matrix signatures, and the induction of the TGF-β signaling in the perigranuloma. A comparison between the proximal and distal muscles to the granuloma revealed an inverse correlation between the distance to the granuloma and the upregulation of cellular response to interferon-γ/α, TNF-α, IL-1,4,6, fibroblast proliferation, epithelial to mesenchymal cell transition, and the downregulation of muscle gene expression. These data shed light on the intercommunications between granulomas and the muscle tissue and provide pathophysiological mechanisms by showing that granuloma immune cells have a direct impact on proximal muscle tissue by promoting its progressive replacement by fibrosis via the expression of pro-inflammatory and profibrosing signatures. These data could possibly explain the evolution towards a state of disability for some patients.

Quality of life in sarcoidosis

Having sarcoidosis often has a major impact on quality of life of patients and their families. Improving quality of life is prioritized as most important treatment aim by many patients with sarcoidosis, but current evidence and treatment options are limited. In this narrative review, we describe the impact of sarcoidosis on various aspects of daily life, evaluate determinants of health-related quality of life (HRQoL), and provide an overview of the different patient-reported outcome measures to assess HRQoL in sarcoidosis. Moreover, we review the current evidence for pharmacological and non-pharmacological interventions to improve quality of life for people with sarcoidosis.

An mTORC1-Dependent Mouse Model for Cardiac Sarcoidosis

Background Sarcoidosis is an inflammatory, granulomatous disease of unknown cause affecting multiple organs, including the heart. Untreated, unresolved granulomatous inflammation can lead to cardiac fibrosis, arrhythmias, and eventually heart failure. Here we characterize the cardiac phenotype of mice with chronic activation of mammalian target of rapamycin (mTOR) complex 1 signaling in myeloid cells known to cause spontaneous pulmonary sarcoid-like granulomas. Methods and Results The cardiac phenotype of mice with conditional deletion of the tuberous sclerosis 2 (TSC2) gene in CD11c+ cells (TSC2fl/flCD11c-Cre; termed TSC2KO) and controls (TSC2fl/fl) was determined by histological and immunological stains. Transthoracic echocardiography and invasive hemodynamic measurements were performed to assess myocardial function. TSC2KO animals were treated with either everolimus, an mTOR inhibitor, or Bay11-7082, a nuclear factor-kB inhibitor. Activation of mTOR signaling was evaluated on myocardial samples from sudden cardiac death victims with a postmortem diagnosis of cardiac sarcoidosis. Chronic activation of mTORC1 signaling in CD11c+ cells was sufficient to initiate progressive accumulation of granulomatous infiltrates in the heart, which was associated with increased fibrosis, impaired cardiac function, decreased plakoglobin expression, and abnormal connexin 43 distribution, a substrate for life-threatening arrhythmias. Mice treated with the mTOR inhibitor everolimus resolved granulomatous infiltrates, prevented fibrosis, and improved cardiac dysfunction. In line, activation of mTOR signaling in CD68+ macrophages was detected in the hearts of sudden cardiac death victims who suffered from cardiac sarcoidosis. Conclusions To our best knowledge this is the first animal model of cardiac sarcoidosis that recapitulates major pathological hallmarks of human disease. mTOR inhibition may be a therapeutic option for patients with cardiac sarcoidosis.

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

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

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.

Simultaneous Assessment of mTORC1, JAK/STAT, and NLRP3 Inflammasome Activation Pathways in Patients with Sarcoidosis

The unknown etiology of sarcoidosis, along with the variability in organ involvement and disease course, complicates the effective treatment of this disease. Based on recent studies, the cellular inflammatory pathways involved in granuloma formation are of interest regarding possible new treatment options, such as the mechanistic (formerly mammalian) target of rapamycin complex 1 (mTORC1) pathway, the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway, and the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome pathway. The aim of this study was to explore the potential coexpression of these three inflammatory pathways in patients with sarcoidosis and see whether possible differences were related to disease outcome. The tissue of 60 patients with sarcoidosis was used to determine the activity of these three signaling pathways using immunohistochemistry. The activation of NLRP3 was present in 85% of all patients, and the activation of mTORC1 and JAK/STAT was present in 49% and 50% of patients, respectively. Furthermore, the presence of NLRP3 activation at diagnosis was associated with a chronic disease course of sarcoidosis. Our finding of different new conceptual inflammatory tissue phenotypes in sarcoidosis could possibly guide future treatment studies using the available inhibitors of either NLRP3, JAK-STAT, and mTORC1 inhibitors in a more personalized medicine approach.

Cellular Recycling Gone Wrong: The Role of Dysregulated Autophagy and Hyperactive mTORC1 in the Pathogenesis of Sarcoidosis

BACKGROUND AND AIMS

Autophagy is a highly regulated, complex intracellular recycling process that is vital to maintaining cellular homeostasis in response to diverse conditions and stressors. Despite the presence of robust regulatory pathways, the intricate and multi-step nature of autophagy creates opportunity for dysregulation. Errors in autophagy have been implicated in the development of a broad range of clinical pathologies including granulomatous disease. Specifically, activation of the mTORC1 pathway has been identified as a key negative regulator of autophagic flux, prompting the study of dysregulated mTORC1 signaling in the pathogenesis of sarcoidosis. Our review: We conducted a thorough search of the extant literature to identify the regulatory pathways of autophagy, and more specifically the implication of upregulated mTORC1 pathways in the pathogenesis of sarcoidosis. We review data showing spontaneous granuloma formation in animal models with upregulate mTORC1 signaling, human genetic studies showing mutation in autophagy genes in sarcoidosis patients, and clinical data showing that targeting autophagy regulatory molecules like mTORC1 may provide new therapeutic approaches for sarcoidosis.

CONCLUSIONS

Given the incomplete understanding of sarcoidosis pathogenesis and the toxicities of current treatments, a more complete understanding of sarcoidosis pathogenesis is crucial for the development of more effective and safer therapies. In this review, we propose a strong molecular pathway driving sarcoidosis pathogenesis at which autophagy is at the center. A more complete understanding of autophagy and its regulatory molecules, like mTORC1, may provide a window into new therapeutic approaches for sarcoidosis.

Tofacitinib, a suppressor of NOD2 expression, is a potential treatment for Blau syndrome

Introduction

Blau syndrome is a rare autosomal dominant autoinflammatory granulomatous disease caused by a mutation in the NOD2 gene. It is characterized by a clinical trial of granulomatous dermatitis, arthritis, and uveitis. Tofacitinib is a pan Janus kinase (JAK) inhibitor used for treatment of Blau syndrome and idiopathic sarcoidosis. Here, we evaluated its effect on inflammatory pathways associated with Blau syndrome. The effect of tofacitinib on downstream pathways regulated by mutant NOD2 was analyzed using luciferase assays with overexpression of NOD2 mutants.

Methods

The effect of tofacitinib on the upstream pathway for the induction of NOD2 expression and proinflammatory cytokine production was assessed using monocytic cell lines differentiated from Blau syndrome patient-derived induced pluripotent stem cells.

Results

Tofacitinib did not suppress the increased spontaneous transcriptional activity of NF-κB by mutant NOD2. In addition, mutant NOD2 was not involved in the transcription of ISRE and GAS, which are activated by type 1 and type 2 interferons (IFN), respectively. On the other hand, IFNγ induced the expression of NOD2, which led to the production of inflammatory cytokines by an autoinflammatory mechanism only in cells with mutant NOD2.

Discussion

Tofacitinib suppressed the induction of NOD2 by IFNγ, thereby inhibiting the production of pro-inflammatory cytokines. Thus, tofacitinib showed anti-inflammatory effects through suppression of NOD2 expression. The JAK inhibitor tofacitinib is a potential therapeutic agent for Blau syndrome because it suppresses the autoinflammation seen in Blau syndrome by inhibiting the expression of NOD2.

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.

Macrophage Biology in Human Granulomatous Skin Inflammation

Cutaneous granulomatoses represent a heterogeneous group of diseases, which are defined by macrophage infiltration in the skin. Skin granuloma can be formed in the context of infectious and non-infectious conditions. Recent technological advances have deepened our understanding of the pathophysiology of granulomatous skin inflammation, and they provide novel insights into human tissue macrophage biology at the site of ongoing disease. Here, we discuss findings on macrophage immune function and metabolism derived from three prototypic cutaneous granulomatoses: granuloma annulare, sarcoidosis, and leprosy.

Sarcoid Heart Disease: Review of Current Knowledge

Sarcoidosis is a granulomatous disease with the potential of multiple organ system involvement and its etiology remains unknown. Cardiac involvement is associated with worse clinical outcome, and has been reported to be 20-30% in white and as high as 58% in Japanese populations with sarcoidosis. Clinical manifestations of cardiac sarcoidosis highly depend on the extent and location of granulomatous inflammation. The most frequent presentations include heart block, tachyarrhythmia, or heart failure. Endomyocardial biopsy is the most specific diagnostic test, but has poor sensitivity due to often patchy involvement. The diagnosis of cardiac sarcoidosis remains challenging due to nonspecific imaging findings. Both 18 F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and cardiac magnetic resonance imaging can be used to evaluate cardiac sarcoidosis, but evaluate different stages of the disease process. FDG-PET detects metabolically active inflammatory cells while cardiac magnetic resonance imaging with late gadolinium enhancement reveals areas of myocardial necrosis and fibrosis. Aggressive therapy of symptomatic cardiac sarcoidosis is often sought due to the high risk of sudden death and/or progression to heart failure. Prednisone 20-40 mg a day is the recommended initial treatment. In refractory or severe cases, higher doses of prednisone, 1-1.5 mg/kg/d (or its equivalent) and addition of a steroid-sparing agent have been utilized. Methotrexate is added most commonly. Long-term improvement has been reported with the use of a combination of weekly methotrexate and prednisone versus prednisone alone. After initiation of treatment, a cardiac FDG-PET scan may be performed 2-3 months later to assess treatment response.

Management of neurosarcoidosis

This is a brief and purposefully practical approach to the therapeutic and rehabilitative management of patients affected by neurological complications of systemic sarcoidosis. The review notes the drugs used and their monitoring, and their role in the series of clinical subgroups identified to form the condition. Treatment guidelines for individual clinical subtypes of the disorder are provided, and the importance of rehabilitative measures and lifestyle changes are emphasised.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

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

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.

Potential Benefits of TNF Targeting Therapy in Blau Syndrome, a NOD2-Associated Systemic Autoinflammatory Granulomatosis

Blau syndrome is a systemic autoinflammatory granulomatous disease caused by mutations in the nucleotide-binding oligomerization domain 2 (NOD2) gene. NOD2 is an intracellular pathogen recognition receptor. Upon binding to muramyl dipeptide (MDP), NOD2 activates the NF-κB pathway, leading to the upregulation of proinflammatory cytokines. Clinical manifestations of Blau syndrome appear in patients before the age of four. Skin manifestations resolve spontaneously in some cases; however, joint and eye manifestations are progressive, and lead to serious complications, such as joint contracture and blindness. Currently, there is no specific curative treatment for the disease. Administration of high-dose oral steroids can improve clinical manifestations; however, treatments is difficult to maintain due to the severity of the side effects, especially in children. While several new therapies have been reported, including JAK inhibitors, anti-IL-6 and anti-IL-1 therapies, anti-TNF therapy plays a central role in the treatment of Blau syndrome. We recently performed an ex vivo study, using peripheral blood and induced pluripotent stem cells from patients. This study demonstrated that abnormal cytokine expression in macrophages from untreated patients requires IFNγ stimulation, and that anti-TNF treatment corrects the abnormalities associated with Blau syndrome, even in the presence of IFNγ. Therefore, although the molecular mechanisms by which the genetic mutations in NOD2 lead to granuloma formation remain unclear, it is possible that prior exposure to TNFα combined with IFNγ stimulation may provide the impetus for the clinical manifestations of Blau syndrome.

Inhibition of type 1 immunity with tofacitinib is associated with marked improvement in longstanding sarcoidosis

Sarcoidosis is an idiopathic inflammatory disorder that is commonly treated with glucocorticoids. An imprecise understanding of the immunologic changes underlying sarcoidosis has limited therapeutic progress. Here in this open-label trial (NCT03910543), 10 patients with cutaneous sarcoidosis are treated with tofacitinib, a Janus kinase inhibitor. The primary outcome is the change in the cutaneous sarcoidosis activity and morphology instrument (CSAMI) activity score after 6 months of treatment. Secondary outcomes included change in internal organ involvement, molecular parameters, and safety. All patients experience improvement in their skin with 6 patients showing a complete response. Improvement in internal organ involvement is also observed. CD4⁺ T cell-derived IFN-γ is identified as a central cytokine mediator of macrophage activation in sarcoidosis. Additional type 1 cytokines produced by distinct cell types, including IL-6, IL-12, IL-15 and GM-CSF, also associate with pathogenesis. Suppression of the activity of these cytokines, especially IFN-γ, correlates with clinical improvement. Our results thus show that tofacitinib treatment is associated with improved sarcoidosis symptoms, and predominantly acts by inhibiting type 1 immunity.

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.

Clinical and immunological study of Tofacitinib and Baricitinib in refractory Blau syndrome: case report and literature review

Blau syndrome (BS) is an autoinflammatory disorder characterized by non-caseating granulomatous dermatitis, arthritis, and uveitis. We present a case of refractory and severe BS that was treated with the Janus kinase inhibitors (JAKINIBS), Tofacitinib (TOFA) and then Baricitinib (BARI). Our aim was to describe the clinical and immunological outcomes after treatment with JAKINIBS. Blood tests and serum samples were obtained during follow-up with TOFA and BARI. We assessed their effects on clinical outcomes, acute phase reactants, absolute lymphocyte counts (ALCs), lymphocyte subset counts, immunoglobulins, and cytokine levels. A review of the literature on the use of JAKINIBS for the treatment of uveitis and sarcoidosis was also conducted. TOFA led to a rapid and maintained disease control and a steroid-sparing effect. A decrease from baseline was observed in ALC, CD3+, CD4+, CD8+, and natural killer (NK) cell counts. B-cells were stable. Serum levels of interleukin (IL)-4 and tumor necrosis factor alpha (TNF-α) increased, whereas IL-2, IL-6, IL-10, and IL-17 maintained stable. TOFA was discontinued after 19 months due to significant lymphopenia. The initiation of BARI allowed maintaining adequate control of disease activity with an adequate safety profile. The literature review showed seven patients with uveitis and five with sarcoidosis treated with JAKINIBS. No cases of BS treated with JAKINIBS were found. We report the successful use of JAKINIBS in a patient with refractory and severe BS.

Clinical settings with tofacitinib in ulcerative colitis

There are aspects of Janus kinase (JAK) inhibitors, specifically tofacitinib, that distinguish them from other drugs used in the treatment of ulcerative colitis (UC), such as their oral administration, their short half-life and their lack of immunogenicity. With the available evidence, we can highlight tofacitinib's quick action and flexibility of use, and its efficacy in patients, irrespective of whether or not they have previously been exposed to TNF inhibitors (anti-TNF drugs) and other biologic agents. Moreover, their safety profile is known and manageable, with certain considerations and precautions being factored in before and during treatment. In this review, we have defined various scenarios pertaining to this drug, e.g. its use in the event of failure or intolerance to previous treatment with biologics, when a quick response is required or in patients with other concurrent immune-mediated diseases.

Emerging insights in sarcoidosis: moving forward through reverse translational research

Sarcoidosis is a chronic granulomatous disease of unknown etiology that primarily affects the lungs. The development of stage IV or fibrotic lung disease accounts for a significant proportion of the morbidity and mortality attributable to sarcoidosis. Further investigation into the active mechanisms of disease pathogenesis and fibrogenesis might illuminate fundamental mediators of injury and repair while providing new opportunities for clinical intervention. However, progress in sarcoidosis research has been hampered by the heterogeneity of clinical phenotypes and the lack of a consensus modeling system. Recently, reverse translational research, wherein observations made at the patient level catalyze hypothesis-driven research at the laboratory bench, has generated new discoveries regarding the immunopathogenic mechanisms of pulmonary granuloma formation, fibrogenesis, and disease model development. The purpose of this review is to highlight the promise and possibility of these novel investigative efforts.

Treatment of Sarcoidosis in US Rheumatology Practices: Data From the American College of Rheumatology's Rheumatology Informatics System for Effectiveness (RISE) Registry

OBJECTIVE

Sarcoidosis is often treated with glucocorticoids, although the use of biologics is growing. Prescribing patterns for biologics for patients with sarcoidosis in US rheumatology practices have never been examined. Given that there are no steroid-sparing US Food and Drug Administration-approved therapies for sarcoidosis, we sought to characterize the real-world treatment of sarcoidosis and to assess practice-level variation in prescribing patterns.

METHODS

We conducted an observational study of patients with sarcoidosis using data from the Rheumatology Informatics System for Effectiveness (RISE) registry (2014-2018). The RISE registry represents an estimated 32% of the US clinical rheumatology workforce. Adult patients with ≥2 codes for sarcoidosis ≥30 days apart were included. We examined sarcoidosis-specific medication use at any time during the study period. Data were analyzed at the practice level.

RESULTS

A total of 3,276 patients with sarcoidosis from 184 practices were included. Of those patients, 75.1% were women, with a mean age of 59.0 ± 12.5 years; 48.3% were White and 27.6% were Black. Overall, 59.3% of patients were prescribed glucocorticoids, and 24.7% received prolonged glucocorticoid therapy (≥10 mg/day for ≥90 days). In all, 12.1% received a biologic or targeted synthetic disease-modifying antirheumatic drug (tsDMARD), most commonly tumor necrosis factor inhibitors. There was wide practice-level variation among 31 practices with ≥30 patients with sarcoidosis; biologic use ranged from 15.6% to 69.2%. Infliximab represented the most common biologic prescribed.

CONCLUSION

In a large sample of US rheumatology practices, 12.1% of patients with sarcoidosis received biologics or tsDMARDs. We found high variability in biologic use across practices. The significant use of long-term glucocorticoids suggests unmet therapeutic needs in this patient population.

Spectrum of Kidney Disorders Associated with T-Cell Immunoclones

Large granular T-cell leukemia is a clonal hematological condition often associated with autoimmune disorders. Whether small-sized T-cell clones that are otherwise asymptomatic can promote immune kidney disorders remains elusive. In this monocentric retrospective cohort in a tertiary referral center in France, we reviewed characteristics of 29 patients with T-cell clone proliferation and autoimmune kidney disorders. Next-generation sequencing of the T-cell receptor of circulating T-cells was performed in a subset of patients. The T-cell clones were detected owing to systematic screening (mean count 0.32 × 10⁹/L, range 0.13–3.7). Strikingly, a common phenotype of acute interstitial nephropathy was observed in 22 patients (median estimated glomerular filtration rate at presentation of 22 mL/min/1.73 m² (range 0–56)). Kidney biopsies showed polymorphic inflammatory cell infiltration (predominantly CD3⁺ T-cells, most of them demonstrating positive phospho-STAT3 staining) and non-necrotic granuloma in six cases. Immune-mediated glomerulopathy only or in combination with acute interstitial nephropathy was identified in eight patients. Next-generation sequencing (n = 13) identified a major T-cell clone representing more than 1% of the T-cell population in all but two patients. None had a mutation of STAT3. Twenty patients (69%) had two or more extra-kidney autoimmune diseases. Acute interstitial nephropathies were controlled with corticosteroids, cyclosporin A, or tofacitinib. Thus, we showed that small-sized T-cell clones (i.e., without lymphocytosis) undetectable without specific screening are associated with various immune kidney disorders, including a previously unrecognized phenotype characterized by severe inflammatory kidney fibrosis and lymphocytic JAK/STAT activation.

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.