Value of serum soluble interleukin-2 receptor as a diagnostic and predictive biomarker in sarcoidosis

[Cutaneous manifestations of sarcoidosis]

Sarcoidosis is a noninfectious, inflammatory multisystem disorder characterized by the idiopathic formation of granulomas. The pathogenesis of sarcoidosis remains only partially understood, although various clinical risk factors and extrinsic triggers have been identified, alongside a maintained Th1-mediated immune response. Clinically, sarcoidosis can present with specific manifestations associated with sarcoidal granulomas observable in histological examinations, as well as nonspecific manifestations. Histology is pivotal for diagnosis. In cases of cutaneous sarcoidosis, systemic involvement must be evaluated. Therapeutic approaches are tailored to the most affected organ. For cutaneous sarcoidosis, treatment options vary based on clinical findings and include local therapies as well as systemic interventions. These encompass corticosteroids and other immunosuppressive or immunomodulatory agents.

Predictive Value of Serum sIL-2R Levels and Th17/Treg Immune Balance for Disease Progression in Patients With Rheumatoid Arthritis-Associated Interstitial Lung Disease

BACKGROUND

This article analyzed the relationship between serum sIL-2R levels and Th17/Treg immune balance in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and their prognostic value.

METHODS

RA patients (n = 311) were retrospectively selected for research and then allocated to the RA and RA-ILD groups. Baseline data and 3-year follow-up records of all patients were attained to assess disease progression. Serum sIL-2R levels were examined with ELISA, and Th17 and Treg cell clusters were tested with flow cytometry, followed by the calculation of the Th17/Treg ratio. The correlation of serum sIL-2R with Th17/Treg and related cytokines (IL-17, IL-6, IL-10, and TGF-β1) in RA-ILD patients were analyzed with Spearman's analysis. ROC curves were plotted for analyzing the performance of serum sIL-2R levels and the Th17/Treg ratio for predicting disease progression in RA-ILD patients. A multivariate Cox regression model was developed to screen independent risk factors for disease progression in RA-ILD patients.

RESULTS

RA-ILD patients had elevated serum levels of sIL-2R, Th17 cells, IL-17, and IL-6 and an increased ratio of Th17/Treg, accompanied by a decreased Treg cell population and IL-10 and TGF-β1 levels. Serum sIL-2R levels were correlated positively with IL-17 levels and the Th17/Treg ratio in RA-ILD patients and negatively with IL-10 levels. DAS28 scores, serum sIL-2R levels, and an elevated Th17/Treg ratio were independent risk factors for disease progression in RA-ILD patients, and increased FEV1 and FEV1/FVC were protective factors.

CONCLUSION

Serum sIL-2R levels in conjunction with Th17/Treg immune balance can assist in predicting 3-year disease progression in RA-ILD patients.

A review of sarcoidosis etiology, diagnosis and treatment

Sarcoidosis is an inflammatory disease characterized by the formation of granulomas in various organs, leading to inflammation and potential organ dysfunction. Symptoms often start with general signs like fatigue, fever, and weight loss, but vary depending on the affected organ. Diagnosis is challenging due to its diverse clinical presentation and lack of a definitive test, while treatment is complicated by the disease's variable course, requiring a personalized approach. This review explores the role of genetic and environmental factors in sarcoidosis etiology, examines current challenges in diagnosis and treatment, and discusses how understanding etiology informs patient management and future treatment strategies.

Phenotypes and Endotypes in Sarcoidosis: Unraveling Prognosis and Disease Course

Sarcoidosis is a multi-system granulomatous disease of unknown etiology. In genetically susceptible individuals, the precipitating factors generate, via immunity mechanisms, a host granulomatous response. The granuloma, for unknown reasons thus far, may resolve or may persist and lead to organ damage and fibrosis. Infectious agents, occupational exposure, obesity, smoking and genetic factors are implicated in the pathogenesis of sarcoidosis. Macrophages are important in granuloma formation, and their M1/M2 phenotype is associated with the prognosis of the disease. CD4+ T helper cells play a central role in the pathogenesis of sarcoidosis. The major contributors appear to be Th1 and Th17.1 cells, whose microenvironmental behavior is dictated by the secretions of macrophages and dendritic cells. Higher levels of Th1 and Th17.1 cells are associated with chronic disease and resistance to corticosteroid treatment. In recent years, advances in the phenotyping of sarcoidosis with the help of HRCT, PET-CT and lung function tests have provided us with a better understanding of the disease. Genetic phenotyping performed by the GenPhenReSa consortium and the SAGA study has led to the recognition of new, distinct phenotypes. The reconstitution of dysregulated autophagy through persistent m-TORC-1 pathways may be a new treatment target in sarcoidosis.

Diagnostic value of soluble Interleukin-2 receptor in patients suffering neurosarcoidosis: A systematic review

Background

Neurosarcoidosis is an inflammatory granulomatous disease. Up to 25% of occult sarcoidosis affecting the nervous system are only detected by autopsy. In addition, in recent years the suspicion arose that the soluble Interleukin-2 Receptor (sIL-2R) might be useful in differentiating between neurosarcoidosis and neurosarcoidosis-like diseases such as neurotuberculosis, multiple sclerosis, or cerebral lymphoma.

Objectives

Therefore, we aimed to systematically review randomized controlled trials (RCT), observational studies, and case-control studies evaluating sIL-2R levels in neurosarcoidosis patients.

Design

For this systematic review, a comprehensive literature search of electronic databases including EMBASE, The Web Of Science, The Cochrane Library, MEDLINE, and Google Scholar was conducted. The search was limited to the English language and publication date up to January 08th, 2024.

Data Sources and Methods

As part of the search strategy conducted, 6 articles met the inclusion criteria. Two independent reviewers extracted the relevant data from each article. In addition, 2 independent reviewers assessed the quality of each study using the Newcastle-Ottawa Scale (NOS).

Results

We included 6 studies comprising 98 patients suffering from neurosarcoidosis, 525 non-sarcoidosis patients, and 118 healthy controls. Included studies were published between 2010 and 2023. Cerebrospinal fluid (CSF) sIL-2R levels differed significantly between neurosarcoidosis patients and multiple sclerosis, vasculitis, and healthy controls whereas serum sIL-2R levels did not reveal sufficient discriminative power. sIL-2R index was able to discriminate neurosarcoidosis from neurotuberculosis, bacterial/viral meningitis, and healthy controls.

Conclusions

In this systematic review, we found indications that sIL-2R may be a useful biomarker for the diagnosis of neurosarcoidosis. To determine an additional diagnostic value of sIL-2R, large prospective studies are needed that not only examine absolute sIL-2R levels in serum or CSF but also the dynamic changes as well as the implications of renal function on sIL-2R levels.

Diagnostic Value of Imaging and Serological Biomarkers in Pulmonary Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of an unknown aetiology. It can exist in many organs. Pulmonary and intrathoracic lymph nodes are most commonly involved. Lung sarcoidosis is uncommon in Asia. However, due to the large population of our country and the development of bronchoscopy, percutaneous lung puncture, and other medical technologies, the number of pulmonary sarcoidosis patients is on the rise. Pulmonary sarcoidosis patients have no obvious symptoms in the early stage, and the clinical manifestations in the later stage may vary from person to person. Eventually, the disease progresses to life-threatening pulmonary fibrosis. Therefore, patients with pulmonary sarcoidosis should receive a timely diagnosis. In recent years, the imaging features and serologic biomarkers of pulmonary sarcoidosis have been continuously studied. The diagnostic value of imaging and serologic biomarkers for pulmonary sarcoidosis is summarized below.

Phenotypes and Serum Biomarkers in Sarcoidosis

Sarcoidosis is a multisystem disease, which is diagnosed on a compatible clinical presentation, non-necrotizing granulomatous inflammation in one or more tissue samples, and exclusion of alternative causes of granulomatous disease. Considering its heterogeneity, numerous aspects of the disease remain to be elucidated. In this context, the identification and integration of biomarkers may hold significance in clinical practice, aiding in appropriate selection of patients for targeted clinical trials. This work aims to discuss and analyze how validated biomarkers are currently integrated in disease category definitions. Future studies are mandatory to unravel the diverse contributions of genetics, socioeconomic status, environmental exposures, and other sociodemographic variables to disease severity and phenotypic presentation. Furthermore, the implementation of transcriptomics, multidisciplinary approaches, and consideration of patients' perspectives, reporting innovative insights, could be pivotal for a better understanding of disease pathogenesis and the optimization of clinical assistance.

Biomarkers in Sarcoidosis: Beginning of a New Era?

At present, no biomarker exists which is truly specific for sarcoidosis and the ones available have modest sensitivity and specificity. The clinical context should dictate the choice of biomarker(s) used to address different clinical questions such as diagnosis, monitoring disease activity or monitoring response to treatment. In the future, in addition to known serum biomarkers, it seems fruitful to further explore a possible role of imaging, exhaled air and even biopsy-related biomarkers in sarcoidosis to guide clinical management.

Diagnosis of Pulmonary Sarcoidosis

Diagnosis of sarcoidosis depends on a compatible clinical and imaging presentation, histologic finding of non-necrotizing granulomatous inflammation, and exclusion of alternative causes of granulomatous diseases. This study has reviewed the diagnostic algorithms and approaches of sarcoidosis.

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

The clinical significance of plasma sCD25 as valuable biomarker for progression and prognosis of tuberculosis

BACKGROUND

sCD25 is an important immune molecule for T cell regulation. Tracking the detection of plasma sCD25 plays an important role in the evaluation of immune function, progression, and prognosis of tuberculosis (TB) patients. This study analyzed the association of plasma sCD25 levels with clinical, laboratory, CT imaging characteristics, and clinical outcome of TB patients.

METHODS

The clinical data of 303 TB patients treated in the Fifth People's Hospital of Suzhou from October 2019 to January 2022 were retrospectively analyzed. The levels of sCD25 in plasma were detected by ELISA. According to the cut-off threshold of plasma sCD25 levels, the patients were divided into a low-value group (Group TB1) and a high-value group (Group TB2). The association of plasma sCD25 levels with clinical, laboratory, and CT imaging characteristics of TB patients, as well as their TB treatment outcome were analyzed.

RESULTS

The levels of plasma sCD25 of patients with TB patients were higher than that of the healthy control group (P < 0.01). Among the 303 TB patients, the levels were increased in Group TB2 patients (0.602 ± 0.216 vs. 1.717 ± 0.604 ng/ml, P < 0.001), and there was a progressive reduction after anti-TB treatment. Furthermore, patients in Group TB2 showed higher positive rates in sputum smear (52.0% vs. 34.3%; P = 0.003), sputum culture (69.7% vs. 56.9%; P = 0.032), Xpert MTB/RIF (66.3% vs. 51.2%; P = 0.013) and TB-DNA (51.5% vs. 31.2%; P = 0.001) than those in Group TB1. Patients in Group TB2 had higher incidence in cough (78.8% vs. 62.3%; P = 0.004), expectoration (64.4% vs. 45.1%; P = 0.001), concomitant extrapulmonary TB (14.1% vs. 5.9%; P = 0.016), cavities (47.9% vs. 34.0%; P = 0.022), and unfavorable outcomes after anti-TB treatment.

CONCLUSION

The clinical, laboratory and radiological manifestations of TB patients with high plasma sCD25 levels indicate that the disease is more severe. Tracking plasma sCD25 detection of TB patients has evident clinical significance. It is noteworthy that when the plasma sCD25 levels are significantly elevated, patients should be cautious of the TB progression and disease severity.

Biomarkers and molecular endotypes of sarcoidosis: lessons from omics and non-omics studies

Sarcoidosis is a chronic granulomatous disorder characterized by unknown etiology, undetermined mechanisms, and non-specific therapies except TNF blockade. To improve our understanding of the pathogenicity and to predict the outcomes of the disease, the identification of new biomarkers and molecular endotypes is sorely needed. In this study, we systematically evaluate the biomarkers identified through Omics and non-Omics approaches in sarcoidosis. Most of the currently documented biomarkers for sarcoidosis are mainly identified through conventional "one-for-all" non-Omics targeted studies. Although the application of machine learning algorithms to identify biomarkers and endotypes from unbiased comprehensive Omics studies is still in its infancy, a series of biomarkers, overwhelmingly for diagnosis to differentiate sarcoidosis from healthy controls have been reported. In view of the fact that current biomarker profiles in sarcoidosis are scarce, fragmented and mostly not validated, there is an urgent need to identify novel sarcoidosis biomarkers and molecular endotypes using more advanced Omics approaches to facilitate disease diagnosis and prognosis, resolve disease heterogeneity, and facilitate personalized medicine.

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.

SACE and IL-2R as serum biomarkers for evaluation of multi-organ involvement and prognosis of sarcoidosis

BACKGROUND

Serum biomarkers in the evaluation of organ involvement and prognostic monitoring of sarcoidosis have not been determined. The purpose of this study was to identify common biomarkers that could be used to assess organ involvement and monitor outcomes in sarcoidosis patients.

METHODS

From Mar 2013 to Sep 2021, patients with newly diagnosed pulmonary sarcoidosis were enrolled in this study in Shanghai Pulmonary Hospital. The information from medical records was retrospectively collected including diagnosis, organ involvement, laboratory tests and follow up data. Differences of continuous variables between groups were analyzed by unpaired Student's t-test. Multivariate logistic regression model was performed to identify potential independent factors associated with multiple organ involvement.

RESULTS

A total of 832 patients were included in the study. There were 339 (40.7%) patients with single organ pulmonary involvement, while 493 (59.3%) patients had two to seven organs involved. Among the routine serum tests, only the serum angiotensin converting enzyme (SACE) level was an independent factor of multiple organ involvement. Compared to those patients without involvement, SACE levels were higher in patients with extra-thoracic lymph node, skin, or spleen involvement as well as abnormal calcium metabolism. Interleukin-2 receptor (IL-2R) levels were higher in patients with extra-thoracic lymph node, spleen involvement and abnormal calcium metabolism than in those without it. The mean levels of SACE and IL-2R showed upward trends paralleling the increase on number of organs involved. In follow up, SACE and IL-2R levels were both decreased in an improved patient group, while there was no obvious difference was noticed before and after treatment in patients with persistent disease.

CONCLUSION

SACE and IL-2R were useful as serum biomarkers in the initial evaluation of organ involvement as well as monitoring prognosis in sarcoidosis.

Clinical diagnostic value of serum soluble IL-2 receptor for stage I sarcoidosis in benign isolated mediastinal and hilar lymphadenopathy

BACKGROUND

Serum soluble interleukin-2 receptor (sIL-2R) is recognized as a marker of T-cell activation and is abnormally elevated in sarcoidosis. However, its value for stage I sarcoidosis in benign granulomatous diseases is unclear.

METHODS

We enrolled 33 stage I sarcoidosis patients, 17 lymph node tuberculosis patients, 15 reactive lymphadenopathy patients, and 11 healthy controls. Serum biomarkers concentrations were collected and collated.

RESULTS

Serum sIL-2R concentrations were the highest in stage I sarcoidosis. The AUC of serum sIL-2R for stage I sarcoidosis was 0.7452 in all subjects and 0.6861 in granulomatous diseases. The AUCs of 2 combined diagnostic forms, sIL-2R with angiotensin-converting enzyme (ACE) and sIL-2R with ACE, erythrocyte sedimentation rate (ESR), and lactate dehydrogenase (LDH) were 0.7994 and 0.891 in all subjects, respectively. In granulomatous disease groups for ROC analysis, the best cut-off value of sIL-2R was 745.00 U/ml with 48.50% sensitivity and 84.40% specificity. The combination of four parameters increased the diagnostic accuracy for stage I sarcoidosis in granulomatous diseases (74.10% sensitivity and 100% specificity). Serum sIL-2R concentrations were positively correlated with serum ACE (r = 0.4652, P = 0.0126).

CONCLUSION

Serum sIL-2R appeared to be valuable in identifying stage I sarcoidosis in a group of benign IMHL disorders.

Diagnostic accuracy of interleukin-2 receptor in sarcoidosis: a systematic review and meta-analysis

INTRODUCTION

Soluble interleukin-2 receptor (sIL-2 R), a valuable diagnostic biomarker for sarcoidosis, has been reported with variable results. Based on the literatures currently accessible, a systematic review and meta-analysis of the diagnostic performance of serum sIL-2 R for sarcoidosis were performed.

METHODS

Relevant studies investigating sIL-2 R for sarcoidosis diagnosis in several databases were searched and data on sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were pooled by STATA 16.0 software. Overall test performance was assessed using summary receiver operating characteristic curves and the area under the curve (AUC). Potential publication bias was assessed by Deeks test.

RESULTS

We included eleven studies involving 1,424 subjects, with 1,099 cases of sarcoidosis and 325 of non-sarcoidosis. The pooled parameters of sIL-2 R in diagnosing sarcoidosis were summarized as follows: sensitivity, 0.85 (95% CI: 0.72-0.93); specificity, 0.88 (95% CI: 0.72-0.96); PLR, 7.3 (95% CI: 2.7-20.1); NLR, 0.17 (95% CI:0.08-0.36); DOR, 44 (95% CI: 8-231); and the AUC, 0.93 (95% CI: 0.90-0.95). No publication bias was identified (P = 0.64).

CONCLUSIONS

Evidence suggests sIL-2 R performs well in diagnosing sarcoidosis. Nevertheless, results of sIL-2 R assay should be interpreted with other diagnostic examinations.

Diagnostic performance of electronic nose technology in sarcoidosis

BACKGROUND

Diagnosing sarcoidosis can be challenging, and a non-invasive diagnostic method is lacking. The electronic nose (eNose) profiles volatile organic compounds in exhaled breath, and has potential as a point-of-care diagnostic tool.

RESEARCH QUESTION

Can we use eNose technology to distinguish accurately between sarcoidosis, interstitial lung disease (ILD) and healthy controls, and between sarcoidosis subgroups?

STUDY DESIGN AND METHODS

In this cross-sectional study, exhaled breath of patients with sarcoidosis, ILD, and healthy controls was analyzed using an eNose (SpiroNose). Clinical characteristics were collected from medical files. Partial least square discriminant and ROC analysis was applied to a training and independent validation cohort.

RESULTS

We included 252 patients with sarcoidosis, 317 with ILD and 48 healthy controls. In the validation cohorts, eNose distinguished sarcoidosis from controls with an AUC of 1.00, and pulmonary sarcoidosis from other ILD (AUC 0.87 (0.82-0.93)) and hypersensitivity pneumonitis (AUC 0.88 (0.75-1.00)). Exhaled breath of sarcoidosis patients with and without pulmonary involvement, pulmonary fibrosis, multiple organ involvement, pathology supported diagnosis, and immunosuppressive treatment showed no distinctive differences. Breath profiles differed between patients with a slightly and highly elevated soluble interleukin-2 receptor level (median cut off 772.0 U/mL; AUC 0.78 (0.64-0.92)).

INTERPRETATION

Patients with sarcoidosis can be distinguished from ILD and healthy controls using eNose technology, indicating that this may facilitate accurate diagnosis in the future. Further research is warranted to understand the value of eNose in monitoring sarcoidosis activity.

Strain Echocardiography Is a Promising Tool for the Prognostic Assessment of Sarcoidosis

Sarcoidosis is a systemic chronic granulomatous disease with significant morbidity and mortality. Although basic transthoracic echocardiography (TTE) is not recommended for the assessment of sarcoidosis, speckle tracking echocardiography (STE) has emerged as more sensitive for the early detection of cardiac sarcoidosis and its outcome. The aim of the study was to assess the utility of left atrial and left ventricular longitudinal STE for the prediction of major adverse cardiac events (MACE) and sarcoidosis relapses. We enrolled 172 consecutive patients with sarcoidosis who underwent TTE and pulmonary function tests (PFTs). All patients were followed for a sarcoidosis relapse and MACE. During a median follow-up of 2217 days, 8 deaths, 23 MACE and 36 sarcoidosis relapses were observed. LV global longitudinal strain (GLS) was significantly lower in patients with MACE (p = 0.025). LV-GLS < 17.13% (absolute value) was identified as a fair predictor of MACE. Concerning the sarcoidosis control, TTE revealed a reduction of the LV ejection fraction (p = 0.0432), tricuspid annular plane systolic excursion (p = 0.0272) and global peak atrial longitudinal strain (PALS, p = 0.0012) in patients with relapses. PALS < 28.5% was the best predictor of a sarcoidosis relapse. Our results highlight a potential role of LV-GLS and PALS as prognostic markers in sarcoidosis, supporting the use of STE in the clinical management of these patients.

Increased Serum Soluble Interleukin-2 Receptor Associated with Severity of Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background

This study aimed to reveal the correlation between serum soluble interleukin-2 receptor (sIL-2R) and prognosis in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

A total of 315 patients diagnosed with AECOPD between December 2017 and June 2020 were enrolled. The patients were divided into the good and adverse groups based on the outcomes. An adverse outcome in COPD exacerbation was defined by the presence of at least one of the following: (1) death from a respiratory cause during hospitalisation or within 1 month of follow-up; (2) intensive care unit admission; (3) invasive or non-invasive mechanical ventilation; and (4) COPD-related emergency visit or readmission within 1 month of follow-up. A good outcome was considered as the absence of all the aforementioned issues. The patients underwent lung function (spirometry) assessment, and clinical and inflammatory profiles were collected. Univariate and multivariate analyses were performed to identify the correlation between serum sIL-2R concentration and other variables related to adverse outcomes of AECOPD. The receiver operating characteristic curve was used to show the predictive ability of sIL-2R for adverse outcomes of AECOPD.

Results

We enrolled 315 patients, of whom 161 and 154 had good and adverse outcomes, respectively. We demonstrated that patients with adverse outcomes of AECOPD had a higher concentration of serum sIL-2R than patients with good outcomes (p < 0.001). The increased serum sIL-2R was positively associated with mMRC scores (p < 0.001), GLOD grades (p < 0.001), frequent exacerbation (p < 0.001), and smoking (p < 0.001) in patients with AECOPD and negatively correlated with pulmonary function (p < 0.001). An elevated sIL-2R level was a predictor for the risk of adverse outcomes in AECOPD with a cut-off value of 860 U/mL.

Conclusion

Increased serum sIL-2R concentration correlated with the risk of the adverse outcomes in AECOPD, indicating that it can be a predictive factor contributing to the diagnosis and assessment of adverse outcomes in patients with AECOPD.

Pediatric sarcoidosis with diagnostic and therapeutical insights

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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.

The Comparative Value of Serum Angiotensin Converting Enzyme (ACE) and Lysozyme and the Use of Polyclonal Antibody Activation in the Work-up of Ocular Sarcoidosis

Background: The diagnosis of ocular sarcoidosis (OS) is difficult to establish in the absence of manifest systemic involvement. To help clinicians reach a diagnosis, we convened a group of experts in 2006 (International Workshop on Ocular Sarcoidosis (IWOS)) to set-up clinical criteria for the diagnosis of ocular sarcoidosis. In addition, laboratory investigational tests represent a much-needed adjunct to ascertain the diagnosis. However, many of these tests have low sensitivity and specificity. Purpose: The aim of our study was to evaluate the usefulness of serum ACE, serum lysozyme and polyclonal antibody activation in the diagnosis of ocular sarcoidosis and compare the frequency of increased serum levels of lysozyme and ACE in proven ocular sarcoidosis or in suspected ocular sarcoidosis. Methods: Serum ACE and lysozyme were assessed in these two groups and their means compared to a group of non-granulomatous (i.e., non-sarcoidosis) uveitis patients. The proportion of elevated serum ACE versus lysozyme was compared in the sarcoidosis patients. Polyclonal antibody activation was measured by establishing exposition of patients to four human commensal herpesviruses (EBV, CMV, HSV and VZV) using ELISA or immunofluorescence and in parallel by performing quantitative complement fixation (CF) serologies. The ratio of elevated CF to positive ELISA/immunofluorescence serologies was calculated. The mean of ratios (polyclonal antibody activation) was compared between ocular sarcoidosis and control groups. Results: Thirty-seven patients (F24/M13) were included in our study including 17 patients with IWOS Level 1 and 2 criteria qualifying for Group 1 (proven sarcoidosis) and 20 ocular sarcoidosis suspect patients. Mean age was 54.52 ± 23.74. Mean serum levels of ACE was 49.17± 29 IU/L in the ocular sarcoidosis group versus 27.4 ± 15.34 IU/L (p ≤ 0.00018, student’s t test) in the control group. Mean serum lysozyme levels was 39.92 ± 55.5 mg/L in the ocular sarcoidosis group versus 10.5 ± 5.8 mg/L (p ≤ 0.0013) in the control group (n = 30). Both tests were elevated in 8/37 (21.6%) patients, elevated ACE and normal lysozyme was noted in 2/37 (5.4%) patients, whereas the proportion of normal ACE/elevated lysozyme was much higher, 23/37 (62.2%). In 4/37 (10.8%) patients, both tests were normal. The mean score of polyclonal activation (N of elevated CF serologies divided by number of viruses to which a patient was exposed) was 0.6 ± 0.33 in the ocular sarcoidosis group versus 0.15 ± 0.2 for the control group (n = 42) (p ≤ 0.00001). Sensitivity and specificity of ACE and lysozyme were, respectively, 27%/96.6% and 83.7%/90%. Sensitivity and specificity of polyclonal antibody activation amounted to 70%/90.4% Conclusion: Lysozyme was found to be much more useful than ACE as a laboratory test to support the diagnosis of ocular sarcoidosis. As shown in a previous study, polyclonal antibody activation appears to be another useful laboratory test supportive of the diagnosis of ocular sarcoidosis.

Elevated Serum Amyloid a Levels Are not Specific for Sarcoidosis but Associate with a Fibrotic Pulmonary Phenotype

Elevated Serum Amyloid A (SAA) levels have been found in several inflammatory diseases, including sarcoidosis. SAA is suggested to be involved in sarcoidosis pathogenesis by involvement in granuloma formation and maintenance. We hypothesized that SAA serum levels would be higher in sarcoidosis compared to other non-infectious granulomatous and non-granulomatous diseases. SAA levels were measured in serum from sarcoidosis, Hypersensitivity pneumonitis (HP), and (eosinophilic) granulomatosis with polyangiitis ((E)GPA) patients. Idiopathic pulmonary fibrosis (IPF) patients were included as non-granulomatous disease group. SAA levels of patients with sarcoidosis (31.0 µg/mL), HP (23.4 µg/mL), (E)GPA (36.9 µg/mL), and IPF (22.1 µg/mL) were all higher than SAA levels of healthy controls (10.1 µg/mL). SAA levels did not differ between the diagnostic groups. When SAA serum levels were analyzed in sarcoidosis subgroups, fibrotic sarcoidosis patients showed higher SAA levels than sarcoidosis patients without fibrosis (47.8 µg/mL vs. 29.4 µg/mL, p = 0.005). To conclude, the observation that fibrotic sarcoidosis patients have higher SAA levels, together with our finding that SAA levels were also increased in IPF patients, suggests that SAA may next to granulomatous processes also reflect the process of fibrogenesis. Further studies should clarify the exact role of SAA in fibrosis and the underlying mechanisms involved.

An update on the diagnosis and management of ocular sarcoidosis

PURPOSE OF REVIEW

Ocular sarcoidosis is one of the most common causes of uveitis worldwide. The diagnosis and treatment of patients with ocular sarcoidosis remains challenging in some cases. It is important for clinicians to keep up to date with new diagnostic and treatment tools for this disease.

RECENT FINDINGS

The International Workshop on Ocular Sarcoidosis diagnostic criteria were first proposed in 2009 and revised in 2017. The new criteria contained two parts: ocular presentation and systemic investigation. The diagnostic value of liver enzymes was reduced in the new criteria, whereas the value placed of lymphopenia and the CD4/CD8 ratio in bronchoalveolar lavage fluid were increased. Despite not being included in the criteria, recent studies have also highlighted the diagnostic value of serum soluble interleukin-2 receptors. Recent ophthalmologic imaging also provides useful insights for the differential diagnosis.Many new treatments for ocular sarcoidosis have been developed in recent years. The introduction of biological immunomodulatory agents for uveitis treatment represents a big improvement. Antitumor necrosis factor-alpha antibodies, including adalimumab, have been proven to be effective for treating ocular sarcoidosis. Many studies have also suggested that other biological agents could be effective and well tolerated. Newer intravitreal dexamethasone and fluocinolone implants have been developed. Patients treated with these implants have experienced good and sustained control of their intraocular inflammation.

SUMMARY

Diagnosis and treatment options for ocular sarcoidosis have changed over time. However, challenges still exist in some difficult patients. Future studies should focus on finding more sensitive biomarkers and developing more effective immunomodulatory treatments with longer efficacy and less side effects.

The IL-2 - IL-2 receptor pathway in health and disease: The role of the soluble IL-2 receptor

The interleukin (IL)-2 - IL-2 receptor (IL-2R) pathway is important in immunity, but is also involved in maintenance of self-tolerance. This paradox is further complicated by shedding of the IL-2Rα chain, revealing soluble (s)IL-2R. Binding of IL-2 to sIL-2R may either reduce or enhance responses depending on the target cell being involved in immunity or self-tolerance. Since sIL-2R levels are increasingly measured in clinical practice, it is detrimental for clinical interpretation to understand the possible functional impact of IL-2R shedding. In this review the role of the IL-2 - IL-2R pathway is explored and the conflicting results on the function of sIL-2R are summarized. Finally, the added value of measuring sIL-2R in different types of diseases is being elaborated upon in terms of diagnosis, follow-up, and prognosis. Adequate interpretation of results is hampered by the apparent gap in our knowledge about the functional role of sIL-2R in immunity and tolerance.