Sarcoidosis: Pitfalls and Challenging Mimickers

Plasma collagen neoepitopes are associated with multiorgan disease in the ACCESS and GRADS sarcoidosis cohorts

INTRODUCTION

The pathogenesis of sarcoidosis involves tissue remodelling mediated by the accumulation of abnormal extracellular matrix, which is partly the result of an imbalance in collagen synthesis, cross-linking and degradation. During this process, collagen fragments or neoepitopes, are released into the circulation. The significance of these circulating collagen neoepitopes in sarcoidosis remains unknown.

METHODS

We employed plasma samples from patients with sarcoidosis enrolled in A Case Control Etiologic Study of Sarcoidosis (ACCESS) and Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS), and healthy control patients recruited from the Yale community. Plasma concentrations of type III and VI collagen degradation (C3M and C6M) and formation (PRO-C3 and PRO-C6) were quantified via neoepitope-specific competitive ELISA, and statistical associations were sought with clinical phenotypes.

RESULTS

Relative to healthy controls, the plasma of both sarcoidosis cohorts was enriched for C3M and C6M, irrespective of corticosteroid use and disease duration. While circulating collagen neoepitopes were independent of Scadding stage, there was a significant association between multiorgan disease and PRO-C3, PRO-C6 and C3M in the ACCESS cohort; PRO-C3 and C6M displayed this property in GRADS. These findings were unrelated to plasma levels of interleukin-4 (IL-4), IL-5, IL-6, IL-9, IL-10 and IL-13. Moreover, PRO-C3 was associated with dermatological disease in both cohorts.

DISCUSSION

In two well-characterised sarcoidosis cohorts, we discovered that the plasma is enriched for neoepitopes of collagen degradation (C3M and C6M). In multiorgan disease, there was an association with circulating neoepitopes of type III formation (PRO-C3), perhaps mediated by dermatological sarcoidosis. Further investigation in this arena has the potential to foster new insights into the pathogenic mechanisms of this complex disease.

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.

[Fever in rheumatological diseases]

Fever is a frequent and important symptom in patients with rheumatological diseases and can be an expression of activity of the underlying rheumatological disease. There is great variability in the incidence of fever as a symptom of the disease between individual diseases. The growing understanding of the molecular signatures of the diseases can help to explain these discrepancies: A genetic overactivation of potently pyrogenic cytokines is the reason why fever is nearly always present in autoinflammatory syndromes. In contrast, fever is less common in polyarthritis and myositis and mostly limited to severe courses of disease. In the diagnostic work-up of fever, frequent differential diagnoses, such as infections, malignancies, side effects of drugs and hypersensitivity reactions should be considered. This article provides an overview of the physiology of the development of fever, describes the relevance of fever in individual rheumatological diseases and proposes a workflow for the clinical clarification of rheumatological patients who present with fever.

Incidence, management and prognosis of new-onset sarcoidosis post COVID-19 infection

BACKGROUND AND AIM

SARS-CoV-2 infection has been linked to hyperinflammation in multiple organs with a potential mechanistic link with resulting autoimmunity. There have been reports of many inflammatory complications following COVID-19, including sarcoidosis. A literature review on new-onset sarcoidosis following COVID-19 is lacking. We evaluated potential associations between COVID-19 and development of new-onset sarcoidosis.

METHODS

Articles discussing biopsy-proven sarcoidosis after confirmed COVID-19 infection, published 1956 until April 2023, were included. All article types were deemed eligible except opinion and review articles.

RESULTS

A pooled total of 15 patients with new-onset diagnosis of sarcoidosis after COVID-19 infection were included, 45.5% female, mean age 46.1 years (standard deviation 14.7) at onset of sarcoidosis. Patients were from: Europe (n=11); North America (n=2); South America (n=1); Asia (n=1). The mean time between COVID-19 infection and diagnosis of sarcoidosis was 56.3 days, although this ranged from 10 to 140 days. Organ systems predominantly affected by sarcoidosis were: pulmonary (n=11); cutaneous (n=3); cardiac (n=2); ocular (n=1); systemic (n=1) (with overlapping features in certain patients). Sarcoidosis was treated as follows: glucocorticoids (n=8); azathioprine (n=1); cardiac re-synchronisation therapy (n=1); heart transplant (n=1). All patients were reported to have survived, with one requiring intensive care admission.

CONCLUSIONS

Our result suggests there is a potential link between COVID-19 and new-onset sarcoidosis. The potential mechanism for this is through cytokine mediated immune modulation in COVID-19 infection. Obtaining a tissue sample remains key in confirming the diagnosis of sarcoidosis and this may be delayed during active COVID-19 infection.

Efficacy and safety of Infliximab in systemic sarcoidosis according to GenPhenReSa organ-involvement phenotype: a retrospective study of 55 patients

BACKGROUND

Infliximab is currently recommended as a third-line treatment for refractory sarcoidosis. Data in function of clinical phenotype are currently lacking. We evaluated patients' characteristics and responses to infliximab according to their GenPhenReSa cluster.

METHODS

We evaluated clinical and biological characteristics of patients diagnosed with sarcoidosis who received infliximab between September 2008 and April 2019 at our centre.

RESULTS

Fifty-five patients (median disease duration, 87 months) received infliximab: 48 (87%) as a second- or third-line treatment, and 7 (13%) as a first-line treatment. After a median duration of 12 months, 24 (45%) and 14 (25%) patients achieved complete and partial responses, respectively, together with a significant decrease in the number of affected organs and tapering of steroid doses. All patients with neurosarcoidosis (OR 17), 90% in group 2 (ocular-cardiac-cutaneous-CNS, OR 7.4), and approximately two-thirds of those in groups 1 (abdominal organs), 4 (pulmonary-lympho-nodal), and 5 (extrapulmonary), achieved a response, whereas patients in group 3 (musculoskeletal-cutaneous) had a treatment-failure OR of 9. Infliximab could be stopped after complete remission was achieved in 7 patients: 4 relapsed after a median of 6 months. Overall, 36% of patients experienced serious adverse events, mainly infections, which led to treatment cessation in 29% of patients and caused two deaths.

CONCLUSIONS

Other than patients with musculoskeletal-cutaneous involvement (group 3), infliximab led to a good response for patients with CNS (group 2) and liver (group 1) organ-predominant sarcoidosis. However, it led to serious infections and merely suspended sarcoidosis, so further research on factors predictive of relapse is needed.

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.

Pulmonary Sarcoidosis and Immune Dysregulation: A Pilot Study on Possible Correlation

BACKGROUND

Sarcoidosis is a systemic inflammatory disease characterized by an altered inflammatory response.

OBJECTIVE

The aim of this study was to evaluate whether immune system alterations detected by lymphocyte typing in peripheral blood correlate with the severity of sarcoidosis, calculated according to two separate severity scores proposed by Wasfi in 2006 and Hamzeh in 2010.

MATERIALS AND METHODS

Eighty-one patients were recruited, and clinical data and laboratory tests at the time of diagnosis were obtained in order to assess the severity index score and investigate any statistically significant correlation with the cytofluorimetry data.

RESULTS

Our data demonstrated that none of the two scores show an association with the level of total lymphocytes or lymphocyte subclasses.

LIMITATIONS

First of all, the sample taken into consideration is small. The assessment was performed only at disease onset and not during the disease. Furthermore, the severity scores do not take into account disease activity (measured by PET/CT or gallium scintigraphy).

CONCLUSIONS

Lymphocyte subpopulation values at the time of diagnosis do not appear to correlate with disease severity at onset.

Clinical and Histopathologic Characteristics of Recurrent Sarcoidosis in Posttransplant Lungs: 25 Years of Experience

Lung transplantation is the definitive therapy for end-stage pulmonary sarcoidosis. While recurrent sarcoidosis in allografts has been described in several case reports, the incidence and clinicopathologic characteristics remain unclear. In this study, we characterize the clinical and histopathologic features of recurrent sarcoidosis diagnosed in posttransplant lung surveillance transbronchial biopsies (TBBx). We identified 35 patients who underwent lung transplant for pulmonary sarcoidosis during the study period. Among them, 18 patients (51%) experienced recurrent sarcoidosis posttransplant. These included 7 females and 11 males with mean age at recurrence of 51.6 years. The average time interval from transplant to recurrence was 252 days (22 to 984 d). All TBBx contained >4 pieces of alveolated lung tissue with no evidence of International Society for Heart and Lung Transplantation (ISHLT) grade A2, A3, or A4 acute cellular rejection; chronic rejection; or antibody-mediated rejection. There were 33 surveillance TBBx that contained granulomatous inflammation with a mean of 3.6 well-formed granulomas per TBBx (range: 1 to >20). Multinucleated giant cells were identified in 11 TBBx (33.3%), with 1 case containing asteroid bodies. While most of the granulomas were "naked granulomas," 5 cases (15.2%) showed prominent lymphoid cuffing. Two cases showed evidence of fibrosis. One of the granulomas had focal necrosis; however, no infectious organisms were identified by special stains and clinical correlation suggested this case represented recurrent sarcoidosis. Biopsies of recurrent sarcoidosis usually show multiple well-formed granulomas with giant cells in more than half of the cases, while lymphoid cuffing, fibrosis, asteroid bodies, and necrotizing granulomas are uncommon findings. Pathologists should be aware of these features, as recurrence of sarcoidosis following lung transplant occurs in more than half of patients.

Role of tumor necrosis factor-alpha in the central nervous system: a focus on autoimmune disorders

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic immune cytokine that belongs to the TNF superfamily of receptor ligands. The cytokine exists as either a transmembrane or a soluble molecule, and targets two distinct receptors, TNF-α receptor 1 (TNFR1) and TNF-α receptor 2 (TNFR2), which activate different signaling cascades and downstream genes. TNF-α cellular responses depend on its molecular form, targeted receptor, and concentration levels. TNF-α plays a multifaceted role in normal physiology that is highly relevant to human health and disease. In the central nervous system (CNS), this cytokine regulates homeostatic functions, such as neurogenesis, myelination, blood-brain barrier permeability and synaptic plasticity. However, it can also potentiate neuronal excitotoxicity and CNS inflammation. The pleiotropism of TNF-α and its various roles in the CNS, whether homeostatic or deleterious, only emphasizes the functional complexity of this cytokine. Anti-TNF-α therapy has demonstrated effectiveness in treating various autoimmune inflammatory diseases and has emerged as a significant treatment option for CNS autoimmune diseases. Nevertheless, it is crucial to recognize that the effects of this therapeutic target are diverse and complex. Contrary to initial expectations, anti-TNF-α therapy has been found to have detrimental effects in multiple sclerosis. This article focuses on describing the various roles, both physiological and pathological, of TNF-α in the CNS. Additionally, it discusses the specific disease processes that are dependent or regulated by TNF-α and the rationale of its use as a therapeutic target.

The Elusive Sarcoidosis, an Eight-Year Journey to the Diagnosis of Sarcoidosis: A Case Report

We present a unique case of a patient coming to our internal medicine clinic with intermittent diffuse lymphadenopathy and non-specific symptoms for the past eight years. Initially, the patient was thought to have carcinoma of unknown primary origin, given the abnormalities seen in her imaging. The diagnosis of sarcoidosis was also dismissed, given that the patient had not responded to steroids with negative laboratory support. The patient was referred to several specialists, and only after a pulmonary biopsy was a non-caseating granuloma revealed after multiple prior failed biopsies. The patient was placed on infusion therapy and responded positively. This case demonstrates a challenging diagnosis and treatment which emphasizes the importance of considering alternative treatments if the initial therapy fails.

The Risk of Sarcoidosis Misdiagnosis and the Harmful Effect of Corticosteroids When the Disease Picture Is Incomplete

Sarcoidosis is a complex granulomatous disease of unknown etiology. Due to the heterogeneity of the disease, the diagnosis remains challenging in many cases, often at the physician's discretion, requiring a thorough and complex investigation. Many other granulomatous diseases have the potential to mimic sarcoidosis, whether infectious, occupational, or autoimmune diseases and starting an unnecessary corticosteroid treatment can worsen the patient's prognosis, leading to side effects that can be harder to treat than the actual disease.

18F-Fluorodeoxyglucose Positron Emission Tomography in Cardiac Inflammation: An Educational Case Series

We present an illustrative educational case series focused on the use of nuclear imaging in the diagnosis and follow-up of cardiac inflammation. (Level of Difficulty: Intermediate.).

Sarcoid-like Lung Disease as a Reaction to Silica from Exposure to Bentonite Cat Litter Complicated by End-Stage Renal Failure-A Case Report

A 44-year-old woman was admitted to hospital with end-stage renal failure, productive cough, and decreased exercise tolerance. She had owned nine cats, which resulted in long-term exposure (18 years) to silica-containing bentonite cat litter. High-resolution computed tomography of the chest showed micronodular lesions in the lungs, and mild mediastinal lymphadenopathy. A lung biopsy revealed multinucleated giant cells, some of which had birefringent material and Schaumann bodies. X-ray photoelectron spectroscopy revealed the presence of silicon in the lung biopsy specimen, as well as in the patient's cat litter. The pulmonary condition was suggestive of sarcoid-like lung disease, rather than silicosis, sarcoidosis, or hypersensitivity pneumonitis, according to the clinicopathological findings. Renal failure appeared to be a result of chronic hypercalcemia due to extrarenal calcitriol overproduction in activated alveolar macrophages. Ultimately, the patient was diagnosed with sarcoid-like lung disease complicated by end-stage renal failure from exposure to bentonite cat litter. Therapy with steroids, in addition to elimination of the bentonite cat litter exposure, resulted in a significant improvement in the health condition. At a follow-up visit after 4 months, an almost complete resolution of the lung lesions and a significant improvement in renal function were observed.

Sarcoid Uveitis: An Intriguing Challenger

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

Association of spondyloarthritis and sarcoidosis: A retrospective observational population-based matched cohort study

OBJECTIVES

To investigate the association between spondyloarthritis (SpA) and sarcoidosis.

METHODS

An observational retrospective population-based matched cohort study was conducted. Using data from the Spanish Minimum Basic Data Set. All the admissions of patients with SpA reported between 1999 and 2015 were analysed and a control group matched by age, sex and year of admission was selected. Crude and age- and sex-adjusted incidence rates for sarcoidosis were calculated. Generalized linear models were used for trend analysis and unconditional logistic regression models for calculating crude and adjusted odds ratios (ORs) to assess the association between sarcoidosis and SpA.

RESULTS

The study database contained data on 214,280 hospitalisations: 107,140 admissions of patients with SpA and 107,140 of patients without SpA. Overall, 220 of the admissions were of patients with sarcoidosis: 133 (0.12%) in the SpA group and 87 (0.08%) in the non-SpA group (P<0.05). The incidence rates of sarcoidosis were 2.68 and 1.64 per 100,000 per year in the SpA and non-SpA groups, respectively. The trend was similar in the two cohorts. Regarding potential associations between SpA and sarcoidosis, the crude and adjusted ORs were 1.52 (95% CI: 1.16-2.01) and 1.50 (95% CI: 1.14-1.97) overall in patients with SpA, with adjusted ORs of 1.42 (95% CI: 1.03-1.94) and 1.81 (95% CI: 1.29-2.55) in patients with ankylosing spondylitis and psoriatic arthritis, respectively.

CONCLUSIONS

There is a relationship that is not due to chance between sarcoidosis and SpA and specifically that sarcoidosis is significantly associated with ankylosing spondylitis and psoriatic arthritis.

Pulmonary Sarcoidosis: Diagnosis and Differential Diagnosis

Sarcoidosis is a multisystem disorder of unknown origin and poorly understood pathogenesis that predominantly affects lungs and intrathoracic lymph nodes and is characterized by the presence of noncaseating granulomatous inflammation in involved organs. The disease is highly heterogeneous and can mimic a plethora of other disorders, making diagnosis a challenge even for experienced physicians. The evolution and severity of sarcoidosis are highly variable: many patients are asymptomatic and their disease course is generally benign with spontaneous resolution. However, up to one-third of patients develop chronic or progressive disease mainly due to pulmonary or cardiovascular complications that require long-term therapy. The diagnosis of sarcoidosis requires histopathological evidence of noncaseating granulomatous inflammation in one or more organs coupled with compatible clinical and radiological features and the exclusion of other causes of granulomatous inflammation; however, in the presence of typical disease manifestations such as Löfgren’s syndrome, Heerfordt’s syndrome, lupus pernio and asymptomatic bilateral and symmetrical hilar lymphadenopathy, the diagnosis can be established with high level of certainty on clinical grounds alone. This review critically examines the diagnostic approach to sarcoidosis and emphasizes the importance of a careful exclusion of alternative diagnoses.

Correlation between Potential Risk Factors and Pulmonary Embolism in Sarcoidosis Patients Timely Treated

Background. Some studies with inconclusive results have reported a link between sarcoidosis and an increased risk of pulmonary embolism (PE). This study aimed at assessing a possible correlation between potential risk factors and PE in sarcoidosis patients. Methods. A total of 256 sarcoidosis patients (84 males and 172 females; mean age at diagnosis 49 ± 13) were enrolled after giving written informed consent. Clinical evaluations, laboratory and radiology tests were performed to evaluate the presence of pulmonary embolism. Results. Fifteen sarcoidosis patients with PE (4 males and 11 females; mean age at diagnosis 50 ± 11), diagnosed by lung scintigraphy and 241 sarcoidosis patients without PE (80 males and 161 females; mean age at diagnosis 47 ± 13), were observed. There was a statistically significant increase of the presence of antiphospholipid antibodies in the sarcoidosis group with pulmonary embolism. There was no statistically significant difference between the two groups as to smoking habit, obesity or hereditary thrombophilia frequency (p > 0.05, respectively). Conclusions. This study demonstrates a significant correlation between the presence of antiphospholipid antibody positivity and the pulmonary embolism events in our sarcoidosis patients. Furthermore, we propose screening for these antibodies and monitoring, aimed at timely treatment.

Sarcoidosis presenting with glazy mucoid sputum and dyspnea: a case report

BACKGROUND

Patients with pulmonary sarcoidosis commonly present with a dry cough; a productive cough suggests a complicating airway infection or an alternative diagnosis such as tuberculosis or bronchiectasis.

CASE PRESENTATION

A 36-year-old European (Frisian) woman recently diagnosed with pulmonary sarcoidosis presented with debilitating exertional dyspnea and cough productive of glazy mucoid sputum. Several different attempts including video-assisted thoracoscopic biopsies failed to reach a second or alternative diagnosis including an infectious, autoimmune or collagen-vascular condition. She responded to steroids but with poor tolerance to this treatment, which could not be tapered. After she was started on anti-tumor necrosis factor alpha (TNF-α) therapy with infliximab, 200 mg at three-monthly intervals, she has been fine for well over a decade.

CONCLUSIONS

In this patient with sarcoidosis who had a productive cough accompanied by fever, an extensive workup and prolonged follow-up, an alternative or second diagnosis could be ruled out; we therefore conclude that this highly unusual presentation is part of the clinical spectrum of sarcoidosis.