Sarcoidosis: a state of the art review from the Thoracic Society of Australia and New Zealand

Advances in cellular and tissue-based imaging techniques for sarcoid granulomas

Sarcoidosis embodies a complex inflammatory disorder spanning multiple systems, with its origin remaining elusive. It manifests as the infiltration of inflammatory cells that coalesce into distinctive noncaseous granulomas within afflicted organs. Unraveling this disease necessitates the utilization of cellular or tissue-based imaging methods to both visualize and characterize the biochemistry of these sarcoid granulomas. Although hematoxylin and eosin stain, standard in routine use alongside cytological stains have found utility in diagnosis within clinical contexts, special stains such as Masson's trichrome, reticulin, methenamine silver, and Ziehl-Neelsen provide additional varied perspectives of sarcoid granuloma imaging. Immunohistochemistry aids in pinpointing specific proteins and gene expressions further characterizing these granulomas. Finally, recent advances in spatial transcriptomics promise to divulge profound insights into their spatial orientation and three-dimensional (3-D) molecular mapping. This review focuses on a range of preexisting imaging methods employed for visualizing sarcoid granulomas at the cellular level while also exploring the potential of the latest cutting-edge approaches like spatial transcriptomics and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), with the overarching goal of shedding light on the trajectory of sarcoidosis research.

The role of the host-microbiome and metabolomics in sarcoidosis

Sarcoidosis is a complex inflammatory fibrotic disease that affects multiple organ systems. It is characterized by the infiltration of lymphocytes and mononuclear phagocytes, which form non-caseating granulomas in affected organs. The lungs and intrathoracic lymph nodes are the most commonly affected organs. The underlying cause of sarcoidosis is unknown, but it is believed to occur in genetically predisposed individuals who are exposed to pathogenic organisms, environmental contaminants, or self and non-self-antigens. Recent research has suggested that the microbiome may play a role in the development of respiratory conditions, including sarcoidosis. Additionally, metabolomic studies have identified potential biomarkers for monitoring sarcoidosis progression. This review will focus on recent microbiome and metabolomic findings in sarcoidosis, with the goal of shedding light on the pathogenesis and possible diagnostic and therapeutic approaches.

Evaluation of genetic risk, its clinical manifestation and disease management based on 18 susceptibility gene markers among West-Slavonic patients with sarcoidosis

Sarcoidosis is a heterogenous, multisystemic inflammatory disease that primarily affects lungs. In this study, we multiplex genotyped 18 single-nucleotide polymorphisms (SNPs) to replicate the findings from previous genome-wide association studies (GWAS) and candidate gene studies, and extended analyses to different clinical manifestations (Lofgren syndrome and chest X-ray [CXR] stages) including treatment response among West-Slavonic subjects (564 sarcoidosis patients and 301 healthy controls). We confirm the replication (with Bonferroni correction) of ANXA11 rs1049550 as protective variant for sarcoidosis (odds ratio [OR]=0.71, p=1.33×10^-3), non-LS (OR=0.66, p=2.71×10^-4) and CXR stages 2-4 (OR=0.62, p=7.48×10^-5) compared to controls in West-Slavonic population. We also validate the association of risk variants C6orf10 rs3129927 (OR=2.61, p=2.60×10^-8), TNFA rs1800629 (OR=1.56, p=6.65×10^-4), ATF6B rs3130288 (OR=2.75, p=1.06×10^-9) and HLA-DQA1 rs2187668 (OR=1.74, p=8.83×10^-4) with sarcoidosis compared to controls. For sub-phenotypes compared to controls, risk variants C6orf10 rs3129927 (OR=5.35, p=1.07×10^-12), TNFA rs1800629 (OR=2.66, p=5.94×10^-7), ATF6B rs3130288 (OR=5.24, p=5.21×10^-13), LRRC16A rs9295661 (OR=2.97, p=4.29×10^-4), HLA-DQA1 rs2187668 (OR=3.14, p=1.09×10^-6) and HLA-DRA rs3135394 (OR=5.23, p=8.25×10^-13) were associated with LS while C6orf10 rs3129927 (OR=1.96, p=4.27×10^-4) and ATF6B rs3130288 (OR=2.15, p=3.36×10^-5) were associated with non-LS. For CXR stages compared to controls, C6orf10 rs3129927 (OR=3.67, p=3.63×10^-11), TNFA rs1800629 (OR=1.84, p=1.32×10^-4), ATF6B rs3129927 (OR=3.63, p=1.82×10^-11), HLA-DQA1 rs2187668 (OR=2.13, p=9.59×10^-5) and HLA-DRA rs3135394 (OR=3.42, p=3.45×10^-10) were risk variants for early CXR stages 0-1 while C6orf10 rs3129927 (OR=1.99, p=5.51×10^-4), ATF6B rs3129927 (OR=2.23, p=3.52×10^-5) and HLA-DRA rs3135394 (OR=1.85, p=2.00×10^-3) were risk variants for advanced CXR stages 2-4. The present findings nominate gene variants as plausible prognostic markers for clinical phenotypes, treatment response and disease resolution/progression and may form the basis for establishing genotype-phenotype relationships in patients with sarcoidosis among West-Slavonic population.

Systematic and Comprehensive Analysis of tRNA-Derived Small RNAs Reveals Their Potential Regulatory Roles and Clinical Relevance in Sarcoidosis

Introduction

The pathogenesis of sarcoidosis, which involves several systems, is unclear, and its pathological type is non-caseating epithelioid granulomas. tRNA-derived small RNA (tsRNA) is a novel class of short non-coding RNAs with potential regulatory functions. However, whether tsRNA contributes to sarcoidosis pathogenesis remains unclear.

Methods

Deep sequencing technology was used to identify alterations in tsRNA relative abundance profiles between patients with sarcoidosis and healthy controls and quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate. The clinical parameters were analysis to evaluate the clinical feature correlations initially. Target prediction and bioinformatics analysis of validated tsRNA were conducted to explore the mechanisms of tsRNAs in sarcoidosis pathogenesis.

Results

A total of 360 tsRNAs were identified for exact matches. Among them, the relative abundance of three tRNAs (tiRNA-Glu-TTC-001, tiRNA-Lys-CTT-003, and tRF-Ser-TGA-007) was markedly regulated in sarcoidosis. The levels of various tsRNAs were significantly correlated with age, the number of affected systems, and calcium levels in the blood. Additionally, target prediction and bioinformatics analyses revealed that these tsRNAs may play roles in chemokine, cAMP, cGMP-PKG, retrograde endorphin, and FoxO signalling pathways. The related genes, APP, PRKACB, ARRB2, and NR5A1 finding may participate in the occurrence and development of sarcoidosis through immune inflammation.

Conclusion

This study provides novel insights to explore tsRNA as a novel and efficacious pathogenic target of sarcoidosis.

Bilateral lacrimal gland disease: clinical features and outcomes

BACKGROUND

Patients with bilateral lacrimal gland disease are a unique subset of patients where there is a paucity of literature. This presentation often represents systemic disease or malignancy and can cause diagnostic difficulties. We aim to describe the diagnoses and features of bilateral lacrimal gland disease.

METHOD

Retrospective multi-centre case series involving 115 patients with bilateral lacrimal gland disease from 1995 to 2020.

RESULTS

115 patients were included. Their ages ranged from 9 to 85 (mean 47.3 years) with a female predominance (73, 63.5%). The most common category of diagnosis was inflammatory (69, 60%) followed by lymphoproliferative (23, 20%), structural (17, 14.8%) and other conditions (6, 5.2%). The five most common specific diagnoses were IgG4 related disease (20, 17.4%) and idiopathic orbital inflammatory disease (20, 17.4%), lymphoma (16, 13.9%), lacrimal gland prolapse (13, 11.3%), and sarcoidosis (11, 9.6%). Corticosteroid treatment was used most commonly (29, 25.2%) followed by observation (25, 21.7%). At last follow up, the majority of patients had complete resolution, significant improvement with mild residual disease or stable disease without further progression (104, 90.4%).

CONCLUSION

Bilateral lacrimal disease may be due to a range of aetiologies, most of which are systemic. The most common are inflammatory and lymphoproliferative conditions. Due to the wide range of aetiologies of bilateral lacrimal gland disease, it is extremely difficult to accurately determine a cause based on clinical findings alone, highlighting the vital role of lacrimal gland biopsy in patients presenting with bilateral lacrimal gland disease.

Assessment of Experimental Techniques That Facilitate Human Granuloma Formation in an In Vitro System: A Systematic Review

The process of granuloma formation is complex, and due to species differences, the validity of animal studies is somewhat questioned. Moreover, the large number of animals needed to observe the different stages of development also raises ethical questions. Therefore, researchers have explored the use of human peripheral blood mononuclear cells (PBMCs), a heterogeneous population of immune cells, in an in vitro model. This review included in vitro studies that focused on exposing PBMCs—from healthy, sensitized, or diseased individuals—to antigens derived from infectious agents—such as mycobacteria or Schistosoma spp.—or inorganic antigens—such as beryllium. The reviewed studies mainly explored how human in vitro granuloma models can contribute towards understanding the pathogenesis of granulomatous diseases, especially during the early stages of granuloma formation. The feasibility of granuloma modelling was thus largely assessed via experimental techniques including (1) granuloma scoring indices (GI), (2) cell surface markers and (3) cytokine secretion profiling. While granuloma scoring showed some similarities between studies, a large variability of culture conditions and endpoints measured have been identified. The lack of any standardization currently impedes the success of a human in vitro granuloma model.

Review BRAF inhibition and the spectrum of granulomatous reactions

BRAF-inhibitors have emerged as a promising targeted therapy for malignancies with BRAF mutations, particularly metastatic melanoma. However, granulomatous reactions including sarcoidosis and sarcoid-like-reactions have been reported as a consequence of BRAF-inhibition. It is important to adequately characterise these granulomatous reactions including cutaneous manifestations and systemic involvement, in order to guide investigations and management. A literature review was conducted to characterise the spectrum of granulomatous reactions associated with BRAF-inhibitors - identifying 55 reactions affecting 51 patients, with 37 reactions limited to cutaneous involvement. Further, possible correlation with cancer response, mechanisms of granuloma formation, as well as a proposed workup and management approach for these granulomatous reactions are presented.

Sarcoidosis: epidemiology, characteristics, and outcomes over 10 years - a single-center study in Pakistan

Background: Sarcoidosis is a multisystem granulomatous inflammatory disease which remains under-diagnosed in a tuberculosis endemic region such as Pakistan.Rationale: To determine the distribution, clinical characteristics, diagnostic and treatment modalities and the disease course in the Pakistani population.Methods: A cross-sectional review of sarcoidosis patients from Jan-1,2010 to Dec-31,2019 was done. Multivariable logistic and cox-regression models were used to identify the independent risk-factors associated with disease relapse. Kaplan-Meier curves were used to assess the DFS.Results: 222 patients, with mean age 44 ± 12 years, predominantly females (57.7%) and mean BMI 29 ± 6 were diagnosed sarcoidosis. Significant co-morbidities affected 36.5%, 90% were nonsmokers, and 50.3% belonged to moderate SES. Total 178 (80.2%) were symptomatic with 115 (51.8%) having multi-organ involvement. Stage-I radiological disease was predominant (52.5%). Histopathological diagnosis was obtained in 161 (72.5%) patients. Out of 113 mediastinal lymph-nodes, NNGI was present in 99, with highest yield in Station-07 (68.6%). Treatment was instituted in 108/178 (60.7%) symptomatic patients with steroids alone and in 26 (14.6%) with S+IS, with better clinical and radiological response duration in patients receiving steroid monotherapy (p-values=0.01 and 0.001,respectively, along with overall higher survival time (p-value = 0.04). Risk factors identified for relapse included high SES (AOR5.52;95%CI(1.10-28.40),0.04), steroid monotherapy (AOR0.22; 95%CI(0.10-0.87),0.03), symptomatic response after one year (AOR3.40; 95%CI(1.02-11.10),0.04), and radiological response duration (AOR1.10; 95%CI(1.05-1.20),0.04).Conclusion: Sarcoidosis is a dynamic disease with a variable clinical and geographical spectrum but good overall prognosis.

Potential use of biomarkers for the clinical evaluation of sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology and pathogenesis with a heterogeneous clinical presentation. In the appropriate clinical and radiological context and with the exclusion of other diagnoses, the disease is characterized by the pathological presence of non-caseating epithelioid cell granulomas. Sarcoidosis is postulated to be a multifactorial disease caused by chronic antigenic stimulation. The immunopathogenesis of sarcoidosis encompasses a complex interaction between the host, genetic factors and postulated environmental and infectious triggers, which result in granuloma development.The exact pathogenesis of the disease has yet to be elucidated, but some of the inflammatory pathways that play a key role in disease progression and outcomes are becoming apparent, and these may form the logical basis for selecting potential biomarkers.Biomarkers are biological molecules that are altered pathologically. To date, there exists no single reliable biomarker for the evaluation of sarcoidosis, either diagnostically or prognostically but new candidates are emerging. A diagnosis of sarcoidosis ideally requires a biopsy confirming non-caseating granulomas, but the likelihood of progression that requires intervention remains unpredictable. These challenging aspects could be potentially resolved by incorporating biomarkers into clinical practice for both diagnosis and monitoring disease activity.This review outlines the current knowledge on sarcoidosis with an emphasis on pulmonary sarcoidosis, and delineates the understanding surrounding the implication of biomarkers for the clinical evaluation of sarcoidosis.

Sarcoidosis: rarely a single system disorder

Sarcoidosis is a systemic disease with a number of extrapulmonary manifestations, rarely limited to a single system. The objective of this review is to provide a overview of the systemic features of sarcoidosis and their surveillance.

Sarcoidosis is disease that can affect any organ system, resulting in a number of complications that can cause significant morbidity and mortality, including ophthalmological and cardiac complications. A number of investigations play a role in identifying manifestations of sarcoidosis. Respiratory physicians have an important role to play in identifying complications and monitoring patients with sarcoidosis, as they may be the first to encounter them.

Sarcoidosis can involve any organ system, with several complications, particularly ophthalmological and cardiac disease, that are important to recognise in clinical practice and monitor, no matter one's area of expertisehttps://bit.ly/36oLXxm

Tattoo skin reaction as a skin manifestation of systemic sarcoidosis

A 41-year-old man presented with itching of the skin surrounding his tattoos, blurred vision, fever, general fatigue, and arthralgia. Physical examination revealed skin bulges confined to the tattoo ink lines. Histological analyses of the skin revealed non-caseating granulomas surrounding the tattoo inks. Together with other clinical manifestations including uveitis, lymph nodes swelling, and elevated serum angiotensin-converting enzyme and lysozyme, he was diagnosed with systemic sarcoidosis. The administration of prednisolone alleviated the sarcoidosis-related symptoms, including skin changes. This case illustrates that skin changes on tattoos can be a presenting manifestation of systemic sarcoidosis and that skin biopsy is useful in early diagnosis.

Pulmonary Sarcoidosis: A Clinical Update

Sarcoidosis remains difficult to diagnose, assess and treat. The last decade has brought significant diagnostic and therapeutic advances in the field of sarcoidosis including endobronchial ultrasound, 18F-fluorodeoxyglucose positron emission tomography and biologics. In this article we use clinical vignettes to discuss commonly encountered cases to illustrate and explain the application of these, and other advances.

Coexisting schwannoma of the gallbladder and sarcoidosis: a case report

BACKGROUND

Schwannomas originate from Schwann cells, which are constituents of peripheral nerve sheaths, and can occur anywhere in the body at any age. Most occur in soft tissues such as subcutaneous tissues and muscles, occurrence in the abdominal cavity being relatively rare. In particular, schwannomas of the gallbladder are extremely rare. We herein report a rare case of a schwannoma that coexisted with systemic sarcoidosis and presented as a steroid-resistant mass in the gallbladder wall.

CASE PRESENTATION

A 40-year-old woman was found to have thickening of the gallbladder wall during a routine medical examination and was referred to our hospital, where she was found to have granular shadows in the lungs; mediastinal, cervical, intraperitoneal, and inguinal lymphadenopathy; parotid gland enlargement; and an erythematous skin rash. She was diagnosed as having systemic sarcoidosis by transbronchial lung biopsy and bronchoalveolar lavage. All her systemic mass lesions except for the one in the gallbladder resolved or became smaller with steroid treatment. The steroid-resistant gallbladder lesion showed enhancement on contrast-enhanced computed tomography and was shown by endoscopic ultrasonography to be a 30-mm-diameter gallbladder wall lesion. We performed laparoscopic cholecystectomy, which resulted in diagnosis of the steroid-resistant tumor as a schwannoma. Five months after surgery, the patient's prednisolone dosage had been gradually reduced to 5 mg/day and she was doing well with no evidence of recurrence.

CONCLUSION

Resection of a steroid-resistant tumor resulted in diagnosis of schwannoma, enabling reduction in the patient's steroid dosage for sarcoidosis.

Sarcoidosis: Causes, Diagnosis, Clinical Features, and Treatments

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

Hydroxychloroquine in dermatology: New perspectives on an old drug

Hydroxychloroquine is an age-old drug whose use as an immunomodulatory agent with a low side-effect profile continues to expand. We present a review of this drug including recently updated prescribing recommendations and a summary of its clinical application in dermatology. A maximum daily dose of 5.0 mg/kg based on actual body weight and no greater than 400 mg is advised in order to reduce the risk of retinopathy, which is potentially permanent and has an estimated prevalence of 7.5% at 5 years on standard dosing. Baseline ophthalmologic assessment followed by annual screening after 5 years is recommended; however, closer monitoring should be considered in the setting of existing retinopathy, a cumulative dose > 1000 g or renal dysfunction. Hydroxychloroquine is now considered to be safe in pregnancy, and routine glucose-6-phosphate dehydrogenase (G6PD) deficiency testing is not required. Smoking can significantly decrease its efficacy although the reason is still uncertain. Hydroxychloroquine appears to also demonstrate antineoplastic and cardioprotective benefits.

Parkinsonism and neurosarcoidosis: Cause and effect or coincidence?

Movement disorders in demyelinating diseases can be coincidental or secondary to a demyelinating lesion. We here report the first case of coincidental association of neurosarcoidosis and idiopathic Parkinson's disease.

Sarcoidosis in the Middle East

Sarcoidosis, a systemic granulomatous disease of unknown cause, has been described worldwide and in all populations with notable differences in clinical characteristics, organ involvement, disease severity, and prognosis among different ethnic and racial groups. While the exact prevalence of sarcoidosis in the Middle East is unknown, studies from various countries in the region have reported the clinical characteristics of affected patients, along with a few anecdotal reports. A search of the MEDLINE and Google Scholar databases was conducted for relevant English-language articles using the terms “sarcoidosis” and “Middle East” or “sarcoidosis” and “Arabs.” Subsequently, the names of individual countries were used as search terms, replacing “Middle East.” Overall, the clinical picture of patients with sarcoidosis in the Middle East is similar to that reported elsewhere; for example, the disease was more frequent among females and respiratory complaints were the predominant symptoms. Within the region, most patients from Oman were older and female, with arthralgia, hypercalcemia, and eye involvement being more common. Constitutional symptoms were frequent, especially among patients from Iran. Cough was more common among patients from Kuwait and Iran, while dyspnea was the predominant symptom for Saudi patients. Erythema nodosum was more common in the Turkish population. Clustering was seen in patients with Stage I and II of the disease in all countries except Oman. Apart from those in Iran, the prognosis of most patients from the Middle East was excellent.

Bidirectional association between tuberculosis and sarcoidosis

BACKGROUND AND OBJECTIVE

Tuberculosis (TB) and sarcoidosis are both granulomatous diseases with potential interassociations. However, much uncertainty remains; thus, the present study aimed to clarify the association between these diseases.

METHODS

We established two cohorts in this retrospective longitudinal cohort study using data obtained from the Taiwan National Health Insurance Database from 2000 to 2015. One cohort, which comprised 31 221 patients with TB and 62 442 age-, sex- and index year-matched controls, was used to analyse the risk of sarcoidosis; the other cohort comprised 2442 patients with sarcoidosis and 9688 controls and was used to assess the risk of TB. A Cox proportional hazards model adjusted for potential confounders was used in each cohort.

RESULTS

Patients with TB showed an 8.09-fold higher risk of developing sarcoidosis than non-TB subjects (95% CI = 3.66-17.90), whereas patients with sarcoidosis showed a 1.85-fold higher risk of developing TB than non-sarcoidosis subjects (95% CI = 1.36-2.50). The TB subtype analysis revealed the highest risk of developing sarcoidosis in patients with extrapulmonary TB, and the highest risk of developing extrapulmonary TB was observed in patients with sarcoidosis compared with non-sarcoidosis subjects. Patients with TB showed a higher risk of developing sarcoidosis throughout the follow-up period, but patients with sarcoidosis only showed a higher risk of developing TB within the first year.

CONCLUSION

TB is a risk factor for developing sarcoidosis. The results of this bidirectional cohort study also highlight the clinical difficulty of diagnosing sarcoidosis and TB.