A case control etiologic study of sarcoidosis: environmental and occupational risk factors

Air pollution and incident sarcoidosis in central Pennsylvania

Sarcoidosis is a chronic granulomatous disease predominantly affecting the lungs and inducing significant morbidity and elevated mortality rate. The etiology of the disease is unknown but may involve exposure to an antigenic agent and subsequent inflammatory response resulting in granuloma formation. Various environmental and occupational risk factors have been suggested by previous observations, such as moldy environments, insecticides, and bird breeding. Our study investigated the association of air pollution with diagnosis of sarcoidosis using a case-control design. Penn State Health electronic medical records from 2005 to 2018 were examined for adult patients with (cases) and without (controls) an International Classification of Disease (ICD)-9 or -10 code for sarcoidosis. Patient addresses were geocoded and 24-hr residential-level air pollution concentrations were estimated using spatio-temporal models of particulate matter <2.5 μm (PM2.5), ozone, and PM2.5 elemental carbon (EC) and moving averages calculated. In total, 877 cases and 34,510 controls were identified. Logistic regression analysis did not identify significant associations between sarcoidosis incidence and air pollution exposure estimates. However, the odds ratio (OR) for EC for exposures occurring 7-10 years prior did approach statistical significance, and ORs exhibited an increasing trend for longer averaging periods. Data suggested a latency period of more than 6 years for PM2.5 and EC for reasons that are unclear. Overall, results for PM2.5 and EC suggest that long-term exposure to traffic-related air pollution may contribute to the development of sarcoidosis and emphasize the need for additional research and, if the present findings are substantiated, for public health interventions addressing air quality as well as increasing disease surveillance in areas with a large burden of PM2.5 and EC.

Certolizumab-induced sarcoidosis in a patient with psoriatic arthritis - a case report and review of literature

Tumour necrosis factor-α (TNF- α) antagonists are considered a significant therapeutic option in the treatment of sarcoidosis. Nevertheless, their use can also paradoxically result in sarcoidosis-like reactions. Here, we present a case of a 56-year-old patient with psoriatic arthritis who after 3 months of certolizumab therapy developed pulmonary sarcoidosis. Therefore, certolizumab was discontinued and prednisone initiated. Subsequently, 4 months later a complete remission of interstitial lesions was observed. Due to insufficient control of psoriatic arthritis, upadacitinib and methotrexate were prescribed and despite initial improvement, a couple of months later a massive exacerbation of skin psoriasis occurred and the treatment was switched to secukinumab. As of today, no evidence of sarcoidosis recurrence has been noted. Drug-induced sarcoidosis-like reactions (DISR) appear to be less frequently associated with certolizumab rather than with other anti-TNF-α agents. However, specific mechanisms of this phenomenon remain unclear and require future investigation.

The effect of smoking on nontuberculous mycobacterial pulmonary disease and tuberculosis: a nationwide retrospective cohort study

Although smoking is an established risk factor for Mycobacterial infection, the association between smoking and nontuberculous mycobacterial pulmonary disease (NTM-PD) remains unclear. We evaluated the association between smoking and NTM-PD and tuberculosis (TB) using a population-based South Korean nationwide cohort. Using the Korean National Health Insurance Database, we screened individuals over 20 years of age who underwent the national health screening program in 2009. Out of 3,774,308 eligible populations, we identified 2,964 and 26,112 cases of newly developed NTM-PD and TB, respectively. We used multivariate Cox proportional hazards models to estimate the adjusted hazard ratios (aHRs) of risk factors for NTM-PD and TB. The incidence rates for developing NTM-PD and TB were 0.08 and 0.68 per 1,000 person-years, respectively. Current smokers (aHR 0.63, 95% confidence interval [CI] 0.56-0.71) and current heavy smokers (≥ 20 pack-years, aHR 0.74, 95% CI 0.63-0.86) were at lower risk for NTM-PD development than never smokers. On the contrary, current smokers (aHR 1.19, 95% CI 1.15-1.23) and current heavy smokers (aHR 1.27, 95% CI 1.22-1.33) had a higher risk for TB development than never smokers. These trends were augmented if individuals started smoking before age 20 years. In subgroup analyses stratified by age, these trends were prominent in the 40-64 years age range. Current smoking was associated with a decreased risk of NTM-PD and increased risk of TB. These risks were augmented by early smoking initiation and in the middle age population.

The Association Between Air Pollution and Lung Function in Sarcoidosis and Implications for Health Disparities

BACKGROUND

Sarcoidosis is a granulomatous disease with varying courses of disease progression. Environmental exposures are thought to be contributors to disease onset. Exposure to air pollutants such as fine particulate matter (PM2.5) and nitrogen dioxide (NO2) have been identified as contributors to health disparities in lung diseases; little is known about these environmental exposures' associations with disease outcomes in sarcoidosis.

RESEARCH QUESTION

Is higher exposure to PM2.5 and NO2 associated with worse lung function in sarcoidosis?

STUDY DESIGN AND METHODS

We conducted a retrospective, cross-sectional study of individuals with pulmonary sarcoidosis seen from 2005 to 2015. Home addresses at the year of enrollment were geocoded, and exposure to PM2.5 and NO2 was modeled using high-resolution 1 km × 1 km annual surface exposure data during the year of enrollment. Racial and sex differences in exposure were determined. Multivariable linear regression models were used to examine the associations between PM2.5 and NO2 and the pulmonary function test (PFT) measures FVC, FEV1, and Dlco.

RESULTS

Among the 415 individuals in the analysis, Black individuals had significantly higher exposure to PM2.5 and NO2 compared with non-Hispanic White individuals, 12.2 μg/m3 (SD 2.4) vs 11 μg/m3 (SD 2.2) and 6.3 ppb (SD 1.9) vs 5.0 ppb (SD 2.0), respectively. Every 1 μg/m3 higher exposure to PM2.5 was associated with 1.12% lower Dlco% predicted (95% CI, -1.83 to -0.41; P < .05). Every 1 ppb higher exposure to NO2 was associated with 1.04% lower Dlco% predicted (95% CI, -1.91 to -0.18; P < .05) in fully adjusted models. There were no significant associations between these pollutants and either FVC or FEV1% predicted.

INTERPRETATION

Higher exposure to PM2.5 and NO2 was associated with worse Dlco% predicted. Black individuals with sarcoidosis were exposed to higher PM2.5 and NO2 than non-Hispanic White individuals. Air pollution exposure may be a contributor to reported health disparities in sarcoidosis.

Type 1 innate lymphoid cells: a biomarker and therapeutic candidate in sarcoidosis

Sarcoidosis is an inflammatory disease characterized by immune cell-rich granulomas that form in multiple organs. In this issue of the JCI, Sati and colleagues used scRNA-seq and spatial transcriptomics of skin samples from patients with sarcoidosis and non-sarcoidosis granulomatous disease to identify upregulation of a stromal-immune CXCL12/CXCR4 axis and accumulation of type 1 innate lymphoid cells (ILC1s) in sarcoidosis. The accumulation of ILC1s in skin and blood was specific to patients with sarcoidosis and not observed in other granulomatous diseases. The authors used a mouse model of lung granuloma to show that ILCs contribute to granuloma formation and that blockade of CXCR4 reduced the formation of granulomas, providing a proof of concept that sarcoidosis may be treated by CXCR4 blockade to prevent the progression of disease in patients. These results suggest ILC1s could serve as a diagnostic biomarker in sarcoidosis and a potential therapeutic target.

Progress for all: addressing disparities in sarcoidosis

PURPOSE OF REVIEW

The impact of healthcare disparities in the treatment, care, and outcomes of patients with sarcoidosis has been described. There is paucity of literature on ways to address these disparities with a goal to improving health outcomes for patients with sarcoidosis.

RECENT FINDINGS

Recent findings in other respiratory and systemic diseases suggest that multifaceted interventions directed at improving care at various levels including individual, family, and larger societal levels have been successful in dismantling some of the social and structural barriers to care and consequently have resulted in a reduction in disparate disease outcomes. We explore what some of these interventions would look like in sarcoidosis.

SUMMARY

The impact of healthcare disparities in the treatment, care, and outcomes of patients with sarcoidosis has been described. We outline various steps and approaches aimed at addressing these health disparities with a goal to improving outcomes for those most impacted by disease.

New insights gained from cellular landscape changes in myocarditis and inflammatory cardiomyopathy

Advances in the etiological classification of myocarditis and inflammatory cardiomyopathy (ICM) have reached a consensus. However, the mechanism of myocarditis/ICM remains unclear, which affects the development of treatment and the improvement of outcome. Cellular transcription and metabolic reprogramming, and the interactions between cardiomyocytes and non-cardiomyocytes, such as the immune cells, contribute to the process of myocarditis/ICM. Recent efforts have been made by multi-omics techniques, particularly in single-cell RNA sequencing, to gain a better understanding of the cellular landscape alteration occurring in disease during the progression. This article aims to provide a comprehensive overview of the latest studies in myocarditis/ICM, particularly as revealed by single-cell sequencing.

Gastrointestinal Manifestations of Sarcoidosis: A State-of-the-Art, Comprehensive Review of the Literature-Practical Clinical Insights and Many Unmet Needs on Diagnosis and Treatment

This comprehensive literature review explores the involvement of the gastrointestinal (GI) tract in sarcoidosis, a multisystem granulomatous disorder of unknown etiology. GI sarcoidosis presents a diagnostic and therapeutic challenge due to its rarity and nonspecific clinical manifestations, including overlap with other gastrointestinal diseases. We conducted a comprehensive screening of articles addressing the clinical features, diagnostic approaches, and treatment strategies for GI sarcoidosis. Our findings reveal that GI sarcoidosis can affect any part of the gastrointestinal tract, with the stomach and small intestine being the most involved. Clinical presentations range from asymptomatic cases to severe complications such as obstruction and perforation, with reflux being a common symptom. Diagnosis is often delayed due to the nonspecific nature of symptoms and the need for histopathological confirmation. Therapeutic approaches are poorly defined, typically involving corticosteroids as the mainstay of treatment. However, the long-term efficacy and safety of these treatments remain uncertain in this patient group, given the significant risks and complications associated with prolonged glucocorticoid therapy. There is a clear need to develop accurate diagnostic protocols to distinguish GI sarcoidosis from other conditions and to establish standardized therapeutic guidelines to optimize patient outcomes. Further research is essential to enhance our understanding and management of this complex condition.

Identifying sarcoidosis trends using web search and real-world data in Sweden: a retrospective longitudinal study

Web search data are associated with disease incidence, population interest, and seasonal variations. This study aimed to investigate seasonal and geographical variations of web search data for sarcoidosis and to explore its association with external factors and sarcoidosis incidence in Sweden. Therefore, sarcoidosis-related data from Google Ads Keyword Planer (2017-2020) were generated for Sweden according to its 21 counties. The relationship between search volume and season, region, population demographics, environmental factors, and the sarcoidosis incidence listed in the National Patient Register was assessed. Analyses revealed seasonal variations for Sweden with an overall peak in the spring and autumn. Geographical differences were observed, with a higher search volume for north-western counties and the lowest search volume for Stockholm County. At the country level, the search volume was positively associated with the sarcoidosis incidence. Higher male proportion and older mean age were associated with a higher search volume, while a higher proportion of foreign-born residents, humidity, and mean temperature were associated with a lower search volume. Our analyses detected correlations between web search data, sarcoidosis incidence, and external factors. Analyses of sarcoidosis web search data therefore appear to be a valuable approach to disease surveillance to address medical needs and public interest.

Risk of hypersensitivity pneumonitis and other interstitial lung diseases following organic dust exposure

BACKGROUND

Organic dust is associated with hypersensitivity pneumonitis, and associations with other types of interstitial lung disease (ILD) have been suggested. We examined the association between occupational organic dust exposure and hypersensitivity pneumonitis and other ILDs in a cohort study.

METHODS

The study population included all residents of Denmark born in 1956 or later with at least 1 year of gainful employment since 1976. Incident cases of hypersensitivity pneumonitis and other ILDs were identified in the Danish National Patient Register 1994-2015. Job exposure matrices were used to assign individual annual levels of exposure to organic dust, endotoxin and wood dust from 1976 to 2015. We analysed exposure-response relations by different exposure metrics using a discrete-time hazard model.

RESULTS

For organic dust, we observed increasing risk with increasing cumulative exposure with incidence rate ratios (IRR) per 10 unit-years of 1.19 (95% CI 1.12 to 1.27) for hypersensitivity pneumonitis and 1.04 (95% CI 1.02 to 1.06) for other ILDs. We found increasing risk with increasing cumulative endotoxin exposure for hypersensitivity pneumonitis and other ILDs with IRRs per 5000 endotoxin units/m3-years of 1.55 (95% CI 1.38 to 1.73) and 1.09 (95% CI 1.00 to 1.19), respectively. For both exposures, risk also increased with increasing duration of exposure and recent exposure. No increased risks were observed for wood dust exposure.

CONCLUSION

Exposure-response relations were observed between organic dust and endotoxin exposure and hypersensitivity pneumonitis and other ILDs, with lower risk estimates for the latter. The findings indicate that organic dust should be considered a possible cause of any ILD.

TRIAL REGISTRATION NUMBER

j.no.: 1-16-02-196-17.

A framework for exclusion of alternative diagnoses in sarcoidosis

Sarcoidosis is a multisystem granulomatous syndrome that arises from a persistent immune response to a triggering antigen(s). There is no "gold standard" test or algorithm for the diagnosis of sarcoidosis, making the diagnosis one of exclusion. The presentation of the disease varies substantially between individuals, in both the number of organs involved, and the manifestations seen in individual organs. These qualities dictate that health care providers diagnosing sarcoidosis must consider a wide range of possible alternative diagnoses, from across a range of presentations and medical specialties (infectious, inflammatory, cardiac, neurologic). Current guideline-based diagnosis of sarcoidosis recommends fulfillment of three criteria: 1) compatible clinical presentation and/or imaging 2) demonstration of granulomatous inflammation by biopsy (when possible) and, 3) exclusion of alternative causes, but do not provide guidance on standardized strategies for exclusion of alternative diagnoses. In this review, we provide a summary of the most common differential diagnoses for sarcoidosis involvement of lung, eye, skin, central nervous system, heart, liver, and kidney. We then propose a framework for testing to exclude alternative diagnoses based on pretest probability of sarcoidosis, defined as high (typical findings with sarcoidosis involvement confirmed in another organ), moderate (typical findings in a single organ), or low (atypical/findings suggesting of an alternative diagnosis). This work highlights the need for informed and careful exclusion of alternative diagnoses in sarcoidosis.

Occupational exposures and sarcoidosis: a rapid review of the evidence

BACKGROUND

Sarcoidosis is a rare, multisystem, inflammatory condition associated with the formation of granulomas. Diagnosis can be challenging because of non-specific symptoms complicating epidemiological investigations of its aetiology. Despite research efforts, a review of the current state of the evidence is needed.

AIMS

To assess the evidence for an association between occupational exposures and the development of sarcoidosis. To determine if workers in any occupation are at a greater risk of developing sarcoidosis.

METHODS

This rapid review follows the methodology suggested by the World Health Organization. Two electronic databases were systematically searched until April 2022. The methodological quality of the studies was critically appraised, and a best-evidence approach was used to synthesize the results.

RESULTS

Titles and abstracts of 2916 articles were screened, with 67 full-text articles reviewed for eligibility. Among the 13 studies eligible for this review, none were of high quality (i.e. low risk of bias). Six studies exploring the association between sarcoidosis and a range of occupations and exposures, and one previous systematic review were of low quality reporting inconsistent findings. Six studies examined the risk of sarcoidosis associated with occupational silica exposure, two of which were of acceptable quality. Overall, the study methodologies and results were inadequate to support causal relationships.

CONCLUSIONS

There is limited evidence of acceptable methodological quality to assess the risk of sarcoidosis associated with occupational exposures. There is a growing body of research examining occupational exposure to silica and sarcoidosis. Additional high-quality confirmatory research is needed.

Characteristics of Patients with Sarcoidosis with Emphasis on Acute vs. Chronic Forms-A Single Center Experience

Sarcoidosis is a granulomatous disease of unknown etiology that can affect almost any organ. Although the acute form can have spontaneous regression, a certain number of patients can have a chronic form, which leads to an increase in mortality and a decrease in the quality of life. Considering that the risk factors are still unknown, we wanted to compare the characteristics of patients with acute and chronic forms of sarcoidosis in Serbia in order to determine significant differences between them with hopes of contributing to everyday clinical practice. A total of 2380 patients treated in our clinic were enrolled in this study. They were separated into the following two groups: 1126 patients with acute form and 1254 patients with chronic form. They were further compared by gender, smoking status, radiological status, exposition, biomarkers for sarcoidosis, organ involvement, and other comorbidities; the distribution of patients according to regions of Serbia was also noted. Statistical significance was found in radiological findings (p < 0.001), biomarkers (calcium in 24 h urine p < 0.001; chitotriosidase p = 0.001), and the affliction of organs (p < 0.001). The differences noted in this paper could help improve our understanding of this disease.

Sarcoidosis immunopathogenesis - a new concept of maladaptive trained immunity

Sarcoidosis is a chronic immune disease of unknown origin for which we still lack an immunological framework unifying causal agents, host factors, and natural history of disease. Here, we discuss the initial triggers of disease, and how myeloid cells drive granuloma formation and contribute to immunopathogenesis. We highlight recent advances in our understanding of innate immune memory and propose the hypothesis that maladaptive innate immune training connects previous environmental exposure to granuloma maintenance and expansion. Lastly, we consider how this hypothesis may open novel therapeutic avenues, while corticosteroids remain the front-line treatment.

Microblading reaction as a manifestation of systemic sarcoidosis: two case reports and a review of the literature

BACKGROUND

Sarcoidosis is a multisystemic disease characterized by granulomatous inflammation. Sarcoidosis often poses a diagnostic challenge owing to its nonspecific or mild clinical features. In 20-35% of cases, sarcoidosis initially presents on skin. However, skin lesions commonly mimic dermatological conditions. Therefore, it is important to not underestimate the skin manifestations and perform histopathological examinations to make a timely diagnosis.

CASE PRESENTATION

We present two cases of 33-year-old Caucasian female patients with orange-red macules and plaques that developed in the eyebrow area 1 and 6 years after microblading, respectively. Histopathological examination confirmed a diagnosis of sarcoidosis. The lymph nodes and lungs were also affected in both patients.

CONCLUSION

Our two reports suggest that an esthetic procedure involving dermal or subcutaneous injection of foreign materials can trigger the development of cutaneous and systemic sarcoidosis. However, this relationship has not been described yet. Physicians should, therefore, be aware of this complication to properly evaluate and treat such patients in a timely manner.

Uncommon diagnosis of multinodular goiter - isolated extrapulmonary manifestation of sarcoidosis in thyroid gland (scientific case reports)

AIM

By means of the scientific description of two uncommon cases who underwent. surgical resection of multinodous goiter and following histopathological investigation revealing isolated extrapulmonary manifestation of sarcoidosis, this uncommon diagnosis including symptomatology, clinical findings, diagnostic and therapeutic management is to be illustrated.

CASE DESCRIPTIONS

Diagnostics: Scintigraphy of the thyroid gland with a left-thyroid cold node; ultrasound-guided puncture (cytological investigation, non-suspicious).

THERAPY

Elective thyroidectomy with no macroscopic anomalies und no abnormal aspects with regard to surgical tactic and technique. Histopathological investigation: Complete resection specimen of the thyroid gland with granulomatous inflammation consistent with sarcoidosis.

CLINICAL COURSE

Uneventful with no further manifestations of sarcoidosis in the following diagnostics.

DIAGNOSTICS

Ultrasound, inhomogeneous node (37×30×35 mm) of the right thyroideal gland with echo-poor parts and peripheral vascularization; scintigraphy showing marginally compensated unifocal autonomy of the thyroid gland (laboratory parameters, increased serum level of thyroglobulin [632 ng/mL]).

THERAPY

Planned right hemithyroidectomy with confirmed nodous structure of thyroid parenchyma, without suspicious lymph nodes. Histopathological investigation: 33-mm follicular, nodular, encapsulated structure of thyroid parenchyma (diagnosed as follicular adenoma); 2nd opinion: low-grade differentiated carcinoma of thyroid gland with angioinfiltrating growth and granulomatous inflammation of sarcoidosis type. Procedural intent: After tumor-board consultation, completing thyroidectomy was performed within a 5-weeks interval (pT2 pN0[0/1] V1 L0 G3 R0) with subsequent ablating radio'active iodine therapy; 18 F-FDG-PET-CT (several atypical infiltrates within the right upper lobe of the lung) and bronchoscopy with no detection of further manifestation of sarcoidosis.

CONCLUSION

Sarcoidosis is considered a rare granulomatous multi-locular, systemic disease of not completely known etiopathogenesis with substantial heterogeneity. In most cases, it is associated with the lung, but which can become manifest in various organs. Frequently, extrapulmonary manifestations are usually detected as histological findings by coincidence, which require further investigation to find out additional manifestations as well as to exclude florid infection or other granulomatous processes (clarifying competently differential diagnosis). Therapy is only indicated in symptomatic organ manifestations, taking into account the high rate of spontaneous healing and possible side effects.

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.

Application of laboratory models for sarcoidosis research

This manuscript will review the implications and applications of sarcoidosis models towards advancing our understanding of sarcoidosis disease mechanisms, identification of biomarkers, and preclinical testing of novel therapies. Emerging disease models and innovative research tools will also be considered.

Epidemiology of Sarcoidosis

Sarcoidosis is a systemic, granulomatous disease with variable presentation earning it the term "the great mimicker." The current epidemiology confirms that the disease occurs worldwide, affecting both sexes, and all races, ethnicities, and ages. To date, no causal exposure or agent has been identified. The organ systems most frequently affected by sarcoidosis are also those with greatest exposure to the natural world suggesting environmental and lifestyle contributions to the disease. These include particulate matter, microorganisms, nicotine, and obesity. In this article, we review the epidemiology of sarcoidosis and discuss these non-genetic risk factors in the hope of providing important insight into sarcoidosis and stimulating future research.

Menopausal hormone therapy and risk of sarcoidosis: a population-based nested case-control study in Sweden

Sarcoidosis incidence peaks in women between 50 and 60 years old, which coincides with menopause, suggesting that certain sex hormones, mainly estrogen, may play a role in disease development. We investigated whether menopausal hormone therapy (MHT) was associated with sarcoidosis risk in women and whether the risk varied by treatment type. We performed a nested case-control study (2007-2020) including incident sarcoidosis cases from the Swedish National Patient Register (n = 2593) and matched (1:10) to general population controls (n = 20,003) on birth year, county, and living in Sweden at the time of sarcoidosis diagnosis. Dispensations of MHT were obtained from the Swedish Prescribed Drug Register before sarcoidosis diagnosis/matching. Adjusted odds ratios (aOR) of sarcoidosis were estimated using conditional logistic regression. Ever MHT use was associated with a 25% higher risk of sarcoidosis compared with never use (aOR 1.25, 95% CI 1.13-1.38). When MHT type and route of administration were considered together, systemic estrogen was associated with the highest risk of sarcoidosis (aOR 1.51, 95% CI 1.23-1.85), followed by local estrogen (aOR 1.25, 95% CI 1.11-1.42), while systemic estrogen-progestogen combined was associated with the lowest risk compared to never users (aOR 1.12, 95% CI 0.96-1.31). The aOR of sarcoidosis did not differ greatly by duration of MHT use. Our findings suggest that a history of MHT use is associated with increased risk of sarcoidosis, with women receiving estrogen administered systemically having the highest risk.

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.

Treatment of Granulomatous Inflammation in Pulmonary Sarcoidosis

The management of pulmonary sarcoidosis is a complex interplay of disease characteristics, the impact of medications, and patient preferences. Foremost, it is important to weigh the risk of anti-granulomatous treatment with the benefits of lung preservation and improvement in quality of life. Because of its high spontaneous resolution rate, pulmonary sarcoidosis should only be treated in cases of significant symptoms due to granulomatous inflammation, lung function decline, or substantial inflammation on imaging that can lead to irreversible fibrosis. The longstanding basis of treatment has historically been corticosteroid therapy for the control of granulomatous inflammation. However, several corticosteroid-sparing options have increasing evidence for use in refractory disease, inability to taper steroids to an acceptable dose, or in those with toxicity to corticosteroids. Treatment of sarcoidosis should be individualized for each patient due to the heterogeneity of the clinical course, comorbid conditions, response to therapy, and tolerance of medication side effects.

A Retrospective Analysis of 2-Year Follow-Up of Patients with Incidental Findings of Sarcoidosis

INTRODUCTION

Sarcoidosis is a multi-system granulomatous disease most commonly involving the lungs. It may be incidentally diagnosed during imaging studies for other conditions or non-specific symptoms. The appropriate follow-up of incidentally diagnosed asymptomatic stage 1 disease has not been well defined.

OBJECTIVE

To define the clinical course of incidentally diagnosed asymptomatic stage 1 sarcoidosis and propose an algorithm for the follow-up of these patients.

METHODOLOGY

A retrospective case note analysis was performed of all EBUS-TBNA (endobronchial ultrasound-guided transbronchial needle aspiration)-confirmed cases of stage 1 sarcoidosis presenting incidentally to Bristol and Liverpool Interstitial Lung Disease services. Clinical history, serology results, imaging scans, and lung function parameters were examined at baseline, 12, and 24 months. A cost analysis was performed comparing the cost of the current 2-year follow-up guidance to a 1 year follow-up period.

RESULTS

Sixty-seven patients were identified as the final cohort. There was no significant change in the pulmonary function tests over the two-year follow-up period. Radiological disease stability was observed in the majority of patients (58%, n = 29), and disease regression was evidenced in 40% (n = 20) at 1 year. Where imaging was performed at 2 years, the majority (69.8%, n = 37) had radiological evidence of disease regression, and 30.2% (n = 16) showed radiological evidence of stability. All patients remained asymptomatic and did not require therapeutic intervention over the study period.

CONCLUSIONS

Our results show that asymptomatic patients with incidental findings of thoracic lymph nodal non-caseating granulomas do not progress over a 2-year period. Our results suggest that the prolonged secondary-care follow-up of such patients may not be necessary. We propose that these patients are followed up for 1 year with a further year of patient-initiated follow-up (PIFU) prior to discharge.

Blood glucose and lipids are associated with sarcoidosis: findings from observational and mendelian randomization studies

BACKGROUND

Several researches have demonstrated that patients with sarcoidosis accompanied with the abnormality in blood glucose and/or lipids, however, the causal relationship between them remains uncertain. To elucidate the potential association and causality of blood glucose and lipids with sarcoidosis, we conducted a propensity score matching (PSM)-based observational study combined with mendelian randomization (MR) analysis.

METHODS

All subjects in this study were retrospectively collected from Tongji Hospital during 2010 and 2023. 1:1 PSM was employed to control the potential confounders as appropriate. Univariable and multivariable logistic regression analyses were performed to estimate the associations of sarcoidosis with fasting glucose, high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), total cholesterol (TC), and total triglyceride (TG). The further subtype analysis was also conducted. Afterwards, a bidirectional MR analysis based on public data deeply explored the causality among the 5 candidate traits and sarcoidosis, for which the inverse-variance weighted (IVW) method was utilized as the main inferring approach.

RESULTS

In the observational study, a total number of 756 subjects were enrolled, with 162 sarcoidosis patients and 594 non-sarcoidosis participants, while 160 pairs of subjects were matched after PSM. Multivariable logistic regression analysis indicated that HDLC (OR: 0.151; 95% CI: 0.056-0.408; P < 0.001) and TC (OR: 3.942; 95% CI: 2.644-5.877; P < 0.001) were strongly associated with sarcoidosis. Subtype analysis showed that low HDLC was independently correlated to risk of lesions in bronchus and lungs, and mediastinal lymph nodes, while high TC was to cervical lymph nodes. In MR analysis, high fasting glucose, low HDLC, and high TC were identified as the causal factors of sarcoidosis.

CONCLUSION

HDLC and TC had the potential to influence the risk of sarcoidosis, which could be regarded as predictors and may provide new diagnostic and therapeutic targets for sarcoidosis.

Immune mechanisms of granuloma formation in sarcoidosis and tuberculosis

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

Occupational interstitial lung diseases

Millions of workers are exposed to substances known to cause occupational interstitial lung diseases (ILDs), particularly in developing countries. However, the burden of the disease is likely to be underestimated due to under-recognition, under-reporting or both. The diagnosis of occupational ILD requires a high level of suspicion and a thorough occupational history, as occupational and non-occupational ILDs may be clinically, functionally and radiologically indistinguishable, leading to delayed diagnosis and inappropriate management. A potential occupational aetiology should always be considered in the differential diagnosis of ILD, as removal from the workplace exposure, with or without treatment, is a key therapeutic intervention and may lead to significant improvement. In this article, we provide an overview of the 'traditional' inorganic dust-related ILDs but also address idiopathic pulmonary fibrosis and the immunologically mediated chronic beryllium disease, sarcoidosis and hypersensitivity pneumonitis, with emphasis on the importance of surveillance and prevention for reducing the burden of these conditions. To this end, health-care professionals should be specifically trained about the importance of occupational exposures as a potential cause of ILD.

Genetic predisposition to sarcoidosis

Sarcoidosis is a complex systemic disease with clinical heterogeneity based on varying phenotypes and natural history. The detailed etiology of sarcoidosis remains unknown, but genetic predisposition as well as environmental exposures play a significant role in disease pathogenesis. We performed a comprehensive review of germline genetic (DNA) and transcriptomic (RNA) studies of sarcoidosis, including both previous studies and more recent findings. In this review, we provide an assessment of the following: genetic variants in sarcoidosis susceptibility and phenotypes, ancestry- and sex-specific genetic variants in sarcoidosis, shared genetic architecture between sarcoidosis and other diseases, and gene-environment interactions in sarcoidosis. We also highlight the unmet needs in sarcoidosis genetic studies, including the pressing requirement to include diverse populations and have consistent definitions of phenotypes in the sarcoidosis research community to help advance the application of genetic predisposition to sarcoidosis disease risk and manifestations.

Pulmonary sarcoidosis: A comprehensive review: Past to present

Sarcoidosis is a sterile non-necrotizing granulomatous disease without known causes that can involve multiple organs with a predilection for the lung and thoracic lymph nodes. Worldwide it is estimated to affect 2-160/100,000 people and has a mortality rate over 5 years of approximately 7%. For sarcoidosis patients, the cause of death is due to sarcoid in 60% of the cases, of which up to 80% are from advanced cardiopulmonary failure (pulmonary hypertension and respiratory microbial infections) in all races except in Japan were greater than 70% of the sarcoidosis deaths are due to cardiac sarcoidosis. Scadding stages for pulmonary sarcoidosis associates with clinical outcomes. Stages I and II have radiographic remission in approximately 30%-80% of cases. Stage III only has a 10%-40% chance of resolution, while stage IV has no change of resolution. Up to 40% of pulmonary sarcoidosis patients progress to stage IV disease with lung parenchyma fibroplasia, bronchiectasis with hilar retraction and fibrocystic disease. These patients are at highest risk for the development of precapillary pulmonary hypertension, which may occur in up to 70% of these patients. Sarcoid patients with pre-capillary pulmonary hypertension can respond to targeted pulmonary arterial hypertension medications. Stage IV fibrocytic sarcoidosis with significant pulmonary physiologic impairment, >20% fibrosis on HRCT or pre-capillary pulmonary hypertension have the highest risk of mortality, which can be >40% at 5-years. First line treatment for patients who are symptomatic (cough and dyspnea) with parenchymal infiltrates and abnormal pulmonary function testing (PFT) is oral glucocorticoids, such as prednisone with a typical starting dose of 20-40 mg daily for 2 weeks to 2 months. Prednisone can be tapered over 6-18 months if symptoms, spirometry, PFTs, and radiographs improve. Prolonged prednisone may be required to stabilize disease. Patients requiring prolonged prednisone ≥10 mg/day or those with adverse effects due to glucocorticoids may be prescribed second and third line treatements. Second and third line treatments include immunosuppressive agents (e.g., methotrexate and azathioprine) and anti-tumor necrosis factor (TNF) medication; respectively. Effective treatments for advanced fibrocystic pulmonary disease are being explored. Despite different treatments, relapse rates range from 13% to 75% depending on the stage of sarcoid, number of organs involved, socioeconomic status, and geography. CONCLUSION: The mortality rate for sarcoidosis over a 5 year follow up is approximately 7%. Unfortunately, 10%-40% of patients with sarcoidosis develop progressive pulmonary disease, and >60% of deaths resulting from sarcoidosis are due to advance cardiopulmonary disease. Oral glucocorticoids are the first line treatment, while methotrexate and azathioprine are considered second and anti-TNF agents are third line treatments that are used solely or as glucocorticoid sparing agents for symptomatic extrapulmonary or pulmonary sarcoidosis with infiltrates on chest radiographs and abnormal PFT. Relapse rates have ranged from 13% to 75% depending on the population studied.

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

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

Cystic bronchiectasis in sarcoidosis

Pulmonary sarcoidosis can manifest in different radiologic patterns. Typical manifestations in high-resolution computed tomography are bilateral perihilar lymphadenopathy, micronodules, and fibrotic changes. Atypical manifestations are mass-like or alveolar opacities, honeycomb-like cysts, miliary opacities, tracheobronchial involvement, and pleural disease. Cystic bronchiectasis in pulmonary sarcoidosis is rare, with only a few reported cases in the literature. We present another case of cystic bronchiectasis with a honeycomb-like pattern in pulmonary sarcoidosis and with cardiac involvement. This case was presented as an abstract poster at the American Thoracic Society conference in 2022.

Airborne occupational exposures associated with pulmonary sarcoidosis: a systematic review and meta-analysis

The aetiology and pathophysiology of sarcoidosis is ill defined-current hypotheses centre on complex genetic-immune-environmental interactions in an individual, triggering a granulomatous process. The aim of this systematic review is to define and describe which airborne occupational exposures (aOE) are associated with and precede a diagnosis of pulmonary sarcoidosis. The methodology adopted for the purpose was systematic review and meta-analyses of ORs for specified aOE associated with pulmonary sarcoidosis (DerSimonian Laird random effects model (pooled log estimate of OR)). Standard search terms and dual review at each stage occurred. A compendium of aOE associated with pulmonary sarcoidosis was assembled, including mineralogical studies of sarcoidosis granulomas. N=81 aOE were associated with pulmonary sarcoidosis across all study designs. Occupational silica, pesticide and mould or mildew exposures were associated with increased odds of pulmonary sarcoidosis. Occupational nickel and aluminium exposure were associated with a non-statistically significant increase in the odds of pulmonary sarcoidosis. Silica exposure associated with pulmonary sarcoidosis was reported most frequently in the compendium (n=33 studies) and was the most common mineral identified in granulomas. It was concluded that aOE to silica, pesticides and mould or mildew are associated with increased odds of pulmonary sarcoidosis. Equipoise remains concerning the association and relationship of metal dusts with pulmonary sarcoidosis.

Current Applications of Artificial Intelligence in Sarcoidosis

PURPOSE

Sarcoidosis is a complex disease which can affect nearly every organ system with manifestations ranging from asymptomatic imaging findings to sudden cardiac death. As such, diagnosis and prognostication are topics of continued investigation. Recent technological advancements have introduced multiple modalities of artificial intelligence (AI) to the study of sarcoidosis. Machine learning, deep learning, and radiomics have predominantly been used to study sarcoidosis.

METHODS

Articles were collected by searching online databases using keywords such as sarcoid, machine learning, artificial intelligence, radiomics, and deep learning. Article titles and abstracts were reviewed for relevance by a single reviewer. Articles written in languages other than English were excluded.

CONCLUSIONS

Machine learning may be used to help diagnose pulmonary sarcoidosis and prognosticate in cardiac sarcoidosis. Deep learning is most comprehensively studied for diagnosis of pulmonary sarcoidosis and has less frequently been applied to prognostication in cardiac sarcoidosis. Radiomics has primarily been used to differentiate sarcoidosis from malignancy. To date, the use of AI in sarcoidosis is limited by the rarity of this disease, leading to small, suboptimal training sets. Nevertheless, there are applications of AI that have been used to study other systemic diseases, which may be adapted for use in sarcoidosis. These applications include discovery of new disease phenotypes, discovery of biomarkers of disease onset and activity, and treatment optimization.

Identification of Environmental Exposures Associated with Risk of Sarcoidosis in African Americans

Rationale: Sarcoidosis is a racially disparate granulomatous disease likely caused by environmental exposures, genes, and their interactions. Despite increased risk in African Americans, few environmental risk factor studies in this susceptible population exist. Objectives: To identify environmental exposures associated with the risk of sarcoidosis in African Americans and those that differ in effect by self-identified race and genetic ancestry. Methods: The study sample comprised 2,096 African Americans (1,205 with and 891 without sarcoidosis) compiled from three component studies. Unsupervised clustering and multiple correspondence analyses were used to identify underlying clusters of environmental exposures. Mixed-effects logistic regression was used to evaluate the association of these exposure clusters and the 51 single-component exposures with risk of sarcoidosis. A comparison case-control sample of 762 European Americans (388 with and 374 without sarcoidosis) was used to assess heterogeneity in exposure risk by race. Results: Seven exposure clusters were identified, five of which were associated with risk. The exposure cluster with the strongest risk association was composed of metals (P < 0.001), and within this cluster, exposure to aluminum had the highest risk (odds ratio, 3.30; 95% confidence interval [95% CI], 2.23-4.09; P < 0.001). This effect also differed by race (P < 0.001), with European Americans having no significant association with exposure (odds ratio, 0.86; 95% CI, 0.56-1.33). Within African Americans, the increased risk was dependent on genetic African ancestry (P = 0.047). Conclusions: Our findings support African Americans having sarcoidosis environmental exposure risk profiles that differ from those of European Americans. These differences may underlie racially disparate incidence rates that are partially explained by genetic variation differing by African ancestry.

Interstitial Lung Disease and Sarcoidosis

Interstitial lung disease (ILD), a clinically recognized group of diseases resulting in pulmonary fibrosis, affects up to 200 individuals per 100,000 in the United States. Sarcoidosis has a wide range of clinical manifestations including pulmonary fibrosis. Health disparities are prevalent in both ILD and sarcoidosis around socioeconomic status, race, gender, and geographic location. This review outlines the known health disparities, discusses possible determinants of disparities, and outlines a path to achieve equity in ILD and sarcoidosis.

Genetic and geographic influence on phenotypic variation in European sarcoidosis patients

Introduction

Sarcoidosis is a highly variable disease in terms of organ involvement, type of onset and course. Associations of genetic polymorphisms with sarcoidosis phenotypes have been observed and suggest genetic signatures.

Methods

After obtaining a positive vote of the competent ethics committee we genotyped 1909 patients of the deeply phenotyped Genetic-Phenotype Relationship in Sarcoidosis (GenPhenReSa) cohort of 31 European centers in 12 countries with 116 potentially disease-relevant single-nucleotide polymorphisms (SNPs). Using a meta-analysis, we investigated the association of relevant phenotypes (acute vs. sub-acute onset, phenotypes of organ involvement, specific organ involvements, and specific symptoms) with genetic markers. Subgroups were built on the basis of geographical, clinical and hospital provision considerations.

Results

In the meta-analysis of the full cohort, there was no significant genetic association with any considered phenotype after correcting for multiple testing. In the largest sub-cohort (Serbia), we confirmed the known association of acute onset with TNF and reported a new association of acute onset an HLA polymorphism. Multi-locus models with sets of three SNPs in different genes showed strong associations with the acute onset phenotype in Serbia and Lublin (Poland) demonstrating potential region-specific genetic links with clinical features, including recently described phenotypes of organ involvement.

Discussion

The observed associations between genetic variants and sarcoidosis phenotypes in subgroups suggest that gene-environment-interactions may influence the clinical phenotype. In addition, we show that two different sets of genetic variants are permissive for the same phenotype of acute disease only in two geographic subcohorts pointing to interactions of genetic signatures with different local environmental factors. Our results represent an important step towards understanding the genetic architecture of sarcoidosis.

Occupational lung disease: when should I think of it and why is it important?

Exposure to toxic inhalants in the workplace has the potential to cause (in susceptible individuals) almost any major type of lung disease, such as asthma, COPD and interstitial lung diseases. Patients with occupational lung disease will often present to or will be managed by respiratory specialists without training in occupational respiratory medicine, and patients (or their clinicians) may not identify a link between their disease and their current or a past job. Without an awareness of the range of different occupational lung diseases that exist, their similarity to their non-occupational counterparts, and without directed questioning, these conditions may go unidentified. Patients with occupational lung diseases are often in lower paid work and are disproportionally affected by health inequality. Both clinical and socioeconomic outcomes generally improve if cases are identified early. This allows appropriate advice to be given about the risks of ongoing exposure, clinical management, occupational mobility and, in some cases, eligibility for legal compensation. As respiratory professionals, it is important that these cases are not missed, and if needed, are discussed with a physician with specialised expertise. Here we describe some of the most common occupational lung diseases and outline the diagnostic and treatment approach.

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.

Epidemiology of Sarcoidosis in U.S. Veterans from 2003 to 2019

Rationale: United States veterans represent an important population to study sarcoidosis. Their unique history of environmental exposures, wide geographic distribution, and long-term enrollment in a single integrated healthcare system provides an unparalleled opportunity to understand the incidence, prevalence, and risk factors for sarcoidosis. Objectives: To determine the epidemiology, patient characteristics, geographic distribution, and associated risk factors of sarcoidosis among U.S. veterans. Methods: We used data from the Veterans Health Administration (VHA) electronic health record system between 2003 and 2019 to evaluate the annual incidence, prevalence, and geographic distribution of sarcoidosis (defined using the International Classification of Diseases codes). We used multivariate logistic regression to examine patient characteristics associated with sarcoidosis incidence. Results: Among more than 13 million veterans who received care through or paid for by the VHA, 23,747 (0.20%) incident diagnoses of sarcoidosis were identified. Compared with selected VHA control subjects using propensity score matching, veterans with sarcoidosis were more likely to be female (13.5% vs. 9.0%), of Black race (52.2% vs. 17.0%), and ever-tobacco users (74.2% vs. 64.5%). There was an increase in the annual incidence of sarcoidosis between 2004 and 2019 (from 38 to 52 cases/100,000 person-years) and the annual prevalence between 2003 and 2019 (from 79 to 141 cases/100,000 persons). In a multivariate logistic regression model, Black race (odds ratio [OR], 4.49; 95% confidence interval [CI], 4.33-4.65), female sex (OR, 1.64; 95% CI, 1.56-1.73), living in the Northeast compared with the western region (OR, 1.57; 95% CI, 1.48-1.67), history of tobacco use (OR, 1.36; 95% CI, 1.31-1.41), and serving in the Army, Air Force, or multiple branches compared with the Navy (OR, 1.08; 95% CI, 1.03-1.13; OR, 1.10; 95% CI, 1.04-1.17; OR, 1.27; 95% CI, 1.16-1.39, respectively) were significantly associated with incident sarcoidosis (P < 0.0001). Conclusions: The incidence and prevalence of sarcoidosis are higher among veterans than in the general population. Alongside traditionally recognized risk factors such as Black race and female sex, we found that a history of tobacco use within the Veterans Affairs population and serving in the Army, Air Force, or multiple service branches were associated with increased sarcoidosis risk.

Rare Presentations of Sarcoidosis: A Case Series

Sarcoidosis is a systemic disease of unknown etiology with multi-system affection. It typically involves the skin, eyes, hilar lymph nodes, and pulmonary parenchyma. However, as any organ system could be involved, one has to be aware of its atypical manifestations. We present three uncommon manifestations of the disease. Our first case presented with fever, arthralgias, and right hilar lymphadenopathy with a history of tuberculosis in the past. He was treated for tuberculosis but had a relapse of symptoms three months after completion of treatment. The second patient presented with a headache for two months. On evaluation, cerebrospinal fluid examination showed evidence of aseptic meningitis, while an MRI of the brain demonstrated enhancement of the basal meninges. The third patient was admitted with a mass on the left side of the neck for one year. On evaluation, he was found to have left cervical lymphadenopathy, with its biopsy showing non-caseating epitheloid granuloma. Immunofluorescence did not show evidence of leukemia or lymphoma. All the patients had negative tuberculin skin tests and elevated serum angiotensin-converting enzyme levels supporting the diagnosis of sarcoidosis. They were treated with steroids with complete resolution of symptoms and no recurrence at follow-up. Sarcoidosis is an underdiagnosed entity in India. Thus, awareness of the atypical clinical features could lead to early recognition of the disease and its treatment.

Sarcoidosis: Epidemiology and clinical insights

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

FDG PET/CT Imaging of Sarcoidosis

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

Single-cell and spatial transcriptomics reveal aberrant lymphoid developmental programs driving granuloma formation

Granulomas are lumps of immune cells that can form in various organs. Most granulomas appear unstructured, yet they have some resemblance to lymphoid organs. To better understand granuloma formation, we performed single-cell sequencing and spatial transcriptomics on granulomas from patients with sarcoidosis and bioinformatically reconstructed the underlying gene regulatory networks. We discovered an immune stimulatory environment in granulomas that repurposes transcriptional programs associated with lymphoid organ development. Granuloma formation followed characteristic spatial patterns and involved genes linked to immunometabolism, cytokine and chemokine signaling, and extracellular matrix remodeling. Three cell types emerged as key players in granuloma formation: metabolically reprogrammed macrophages, cytokine-producing Th17.1 cells, and fibroblasts with inflammatory and tissue-remodeling phenotypes. Pharmacological inhibition of one of the identified processes attenuated granuloma formation in a sarcoidosis mouse model. We show that human granulomas adopt characteristic aspects of normal lymphoid organ development in aberrant combinations, indicating that granulomas constitute aberrant lymphoid organs.

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.

Heterogeneity of Lung Function Phenotypes in Sarcoidosis: Role of Race and Sex Differences

Rationale: Historically, sarcoidosis was described as a restrictive lung disease, but several alternative phenotypes of pulmonary function have been observed. Pulmonary function phenotypes in sarcoidosis may represent different clinical and/or molecular phenotypes. Objectives: To characterize the prevalence of different pulmonary function phenotypes in a large and diverse sarcoidosis cohort from a tertiary care referral center. Methods: We identified individuals seen between 2005-2015 with a confirmed diagnosis of sarcoidosis. Data were collected from the first pulmonary function test (PFT) performed at our institution which included spirometry and diffusing capacity of the lung for carbon monoxide (DlCO). Demographics and clinical data were collected. Chi-squared analyses and multiple linear regressions were done to assess statistical differences and associations. Global Lung Function Initiative equations were used to calculate percent predicted measurements for spirometry and DlCO. Results: Of 602 individuals with sarcoidosis, 93% (562) had pulmonary involvement, 64% (385) were female, and 57% (341) were Black. Of those with pulmonary involvement, 56% had abnormal pulmonary function. Lung function impairment phenotypes included: 47% restriction, 22% obstruction, 15% isolated reduction in DlCO, and 16% combined obstructive restrictive phenotype. Restriction was the most common PFT phenotype among Black individuals (41%), while no lung impairment was most common among White individuals (66%) (P < 0.001). Males more frequently had obstruction (19%) compared with females (9%) P = 0.001, and females had more restriction (30%) compared with males (21%) P = 0.031. Conclusions: Among individuals with sarcoidosis and pulmonary function impairment, less than half demonstrated a restrictive phenotype. There were significant differences in pulmonary function phenotypes by race and sex.

Sarcoidosis in Johannesburg, South Africa: A retrospective study

Background

Sarcoidosis is a multisystem granulomatous condition of uncertain aetiology that most frequently affects the lungs. Because of clinical and radiological similarities with tuberculosis (TB), particularly in high-prevalence regions, sarcoidosis is frequently misdiagnosed as TB.

Objectives

To review the clinical features of sarcoidosis patients in a South African (SA) population, adding clinical information to the relatively few studies that have been conducted in SA patients with sarcoidosis.

Methods

This was a retrospective study of 102 sarcoidosis patients conducted between 2002 and 2006 at the Charlotte Maxeke Johannesburg Academic Hospital.

Results

Of 102 sarcoidosis patients, there were 69 (67.6%) females and 33 (32.4%) males. The majority (85.3%) were non-smokers. The mean age of the group was 44.6 years. One-third of patients had chronic comorbid diseases. Almost 17% had been treated initially for TB, prior to being diagnosed as having sarcoidosis. Two patients developed active TB while receiving corticosteroid treatment for sarcoidosis. The salient clinical manifestations were dry cough (the most common presenting symptom in 82.4%), dyspnoea in 53.9%, cutaneous lesions other than erythema nodosum in 33.3%, and on lung examination crackles were noted in 37.3% of patients. Raised angiotensin-converting enzyme (ACE) levels were found in 56.8% of patients. The majority (48%) of patients had stage II chest radiographic changes. Cutaneous (28.4%), mediastinal lymph node (25.5%) and transbronchial lung (25.5%) biopsies were the most frequent sites confirming granulomatous inflammation. Overall, 21.2% of patients had obstructive airway disease. Systemic corticosteroids were indicated in 87.3% of patients and the relapse rate was 60.7%.

Conclusion

Sarcoidosis is often initially misdiagnosed as TB in SA. The most common biopsy sites for histological confirmation were the skin and mediastinal lymph nodes, and transbronchial lung biopsies were also frequently taken. Stage II chest radiographic changes were most common. Overall, systemic corticosteroids were administered in 87.3% of cases and the relapse rate was 60.7%.

Two Cases with Isolated Splenic Sarcoidosis Diagnosed by an Ultrasound-guided Fine-needle Aspiration Biopsy

Asymptomatic splenic nodules were detected incidentally in two middle-aged women at an annual checkup. They showed no abnormalities on laboratory tests, but imaging studies revealed splenic nodules. No other localized lesions were found. Splenic nodules were hypoechoic on ultrasonography (US), hypovascular on contrast-enhanced computed tomography, and showed a low intensity on T2-weighted magnetic resonance imaging. We performed US-guided percutaneous aspiration biopsies using 21-gauge needles without complications, including bleeding. Pathological specimens showed noncaseating granulomas, so both patients were diagnosed with isolated splenic sarcoidosis. A US-guided fine-needle aspiration biopsy is a safe and useful method for diagnosing splenic nodules.

Genetics of neurosarcoidosis

Sarcoidosis is a systemic, inflammatory, granulomatous disease characterized by great variability in organ involvement, clinical course, and severity. While pulmonary manifestations are almost universal, the central and peripheral nervous systems can also be affected. Neurosarcoidosis occurs in ∼5-15% of cases and is among the manifestations with the highest morbidity and mortality. It is known that sarcoidosis has genetic underpinnings and while multiple studies aimed at identifying associations to sarcoidosis susceptibility and prognosis, very few studies have focused on neurosarcoidosis. This review summarizes the genetic studies to date, compares and contrasts those findings with other genetic effects in sarcoidosis, and offers ideas for moving the field forward.

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.

Outcomes after transvenous defibrillator implantation in cardiac sarcoidosis: A systematic review

Introduction

Sarcoidosis is a systemic inflammatory disorder associated with ventricular arrhythmias (VAs) and sudden death in the context of cardiac involvement. Guidelines advocate implantable cardioverter-defibrillator (ICD) implantation in specific subcohorts, but there is a paucity of data on outcomes.

Methods and Results

A systematic review was performed to assess outcomes in patients with definite or probable cardiac sarcoidosis (CS) treated with ICD. Observational studies were identified from multiple databases from inception to 21st May 2021. Outcomes of interest included appropriate and inappropriate ICD therapies in addition to all-cause mortality. Study quality was assessed individually using the Newcastle Ottawa Scale (NOS).Eight studies were identified comprising 530 patients, with follow-up period of 24-66 months (weighted average 40 months). Mean age was 53.9 years with ejection fraction of 41.3%. Overall incidence of appropriate therapy was 38.1% during follow-up. Left ventricular systolic dysfunction (LVSD) with ejection fraction <40% was a predictor of appropriate therapy in the majority of studies, as were sustained VAs during electrophysiological testing (EP) in one study. There was no interaction with device indication (i.e. primary or secondary). Where documented, inappropriate therapy was primarily driven by atrial arrhythmias. All-cause mortality was 6.0% over a median follow-up period of 42 months. Only three studies achieved good quality in the comparability domain of NOS.

Conclusions

Appropriate ICD therapy in patients with CS is commonly associated with LVSD, which can act as a surrogate for scar burden. The utility of EP testing in this setting remains unclear.