Prognostic Biomarkers of Sarcoidosis: A Comparative Study of Serum Chitotriosidase, ACE, Lysozyme, and KL-6

Krebs von den Lungen-6 as biomarker of the new progressive fibrotic phenotype of interstitial lung disease

BACKGROUND

Novel progressive fibrotic phenotype has recently been proposed characterized by progressive and inexorable worsening of the disease. Krebs von den Lungen-6 (KL-6) has been proposed as fibrotic-ILD biomarker. We aimed to assess the role of KL-6 in fibrotic-ILD and the progressive phenotype in accordance with serial serum KL-6.

METHODS

107 patients were enrolled in the study (median age,IQR, 65(54-71)y/o) followed at respiratory diseases and rheumatology units of University of Siena. Thirty-five had diagnoses of IPF, 18 sarcoidosis, 10 PLCH, 5 LAM, 24 fibrotic HP(fHP), 13 RA (4/13 RA-ILD) and 22 SSc (18/22 SSc-ILD). Serial serum samples were collected before therapy (t0) and 24 months later (t1) from IPF, SSc- and RA-ILD patients. Twenty-two healthy controls (HC) were enrolled. Serum samples were assayed for KL-6 concentrations (Fujirebio Europe, Gent, Belgium).

RESULTS

Higher KL-6 concentrations were reported in IPF, fHP and SSc-ILD patients than HC (p<0.0001). KL-6 cut-off value of 885 U/mL identified fibrotic-ILD patients. Logistic regression analysis indicated KL-6 (p=0.004) and smoking-habit (p=0.005) affected the ILD diagnosis. The decision tree model showed KL-6>1145 U/mL, DLco≤60.15 %, FVC≤86 % to classify 86 % IPF patients. Inverse correlation between T0-KL-6 and T1-FVC%(r=-0.314, p=0.046) and T1-DLco%(r=-0.327, p=0.038) in the progressive group.

CONCLUSION

KL-6 proved to be a reliable marker for diagnosis and prognosis of fibrotic ILD patients with predictive value in progressive fibrotic patients and a useful marker to identify the new and similar progressive phenotype of IPF and SSc-ILD patients assessing the functional progression in accordance with serial serum KL-6 measurements.

Utility of microRNA analysis in exhaled breath condensate of sarcoidosis and mediastinal tuberculosis patients: a pilot study

Background

Sarcoidosis and tuberculosis (TB) are the two most common causes of granulomatous mediastinal lymphadenopathy. These often exhibit overlapping clinical and radiological characteristics, rendering accurate diagnosis difficult. MicroRNA (miRNA) analysis is increasingly utilised as a potential biomarker for various diseases. Exhaled breath condensate (EBC) is a noninvasive technique for biomarker evaluation in different respiratory conditions. We attempted to identify differentially expressed miRNAs in the EBC of sarcoidosis and mediastinal TB patients.

Methods

EBC was obtained from subjects with a definitive diagnosis of sarcoidosis and mediastinal TB. EBC was also obtained from age- and sex-matched control subjects. From EBC, miRNA isolation, cDNA preparation and qPCR array were performed. Differentially expressed miRNAs were shortlisted. Further validation was conducted in the EBC of a new subset.

Results

Subjects with a definitive diagnosis of sarcoidosis (50) and TB (50), and control subjects (50) were included. qPCR array from EBC (20 subjects from each group) shortlisted eight differentially expressed miRNAs (miR-126, miR-132, miR-139-3p, miR-139-5p, miR-181c, miR-454, miR-512-3p and miR-362-5p). In the validation set (EBC of 30 subjects from each group), miR-126 and miR-132 were differentially expressed significantly. The miR-126 and miR-132 expression ratio could differentiate sarcoidosis from mediastinal TB with an AUC of 0.618 (82% specificity and 41% sensitivity).

Conclusion

While EBC miRNA expression is significantly and differently altered in sarcoidosis and mediastinal TB, a simple ratiometric approach failed to provide clinically useful signatures for differentiating between the two in patients with mediastinal lymphadenopathy.

Innovations in the care of childhood interstitial lung disease associated with connective tissue disease and immune-mediated disorders

Childhood interstitial lung disease (chILD) associated with connective tissue and immune mediated disorders is the second most common chILD diagnostic category. As knowledge of the molecular and genetic underpinnings of these rare disorders advances, the recognized clinical spectrum of associated pulmonary manifestations continues to expand. Pulmonary complications of these diseases, including ILD, confer increased risk for morbidity and mortality and contribute to increased complexity for providers tasked with managing the multiple organ systems that can be impacted in these systemic disorders. While pulmonologists play an important role in diagnosis and management of these conditions, thankfully they do not have to work alone. In collaboration with a multidisciplinary team of subspecialists, the pulmonary and other systemic manifestations of these conditions can be managed effectively together. The goal of this review is to familiarize the reader with the classic patterns of chILD and other pulmonary complications associated with primary immune-mediated disorders (monogenic inborn errors of immunity) and acquired systemic autoimmune and autoinflammatory diseases. In addition, this review will highlight current, emerging, and innovative therapeutic strategies and will underscore the important role of multidisciplinary management to improving outcomes for these patients.

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.

Blau Syndrome: Challenging Molecular Genetic Diagnostics of Autoinflammatory Disease

The aim of this study was to describe the clinical and molecular genetic findings in seven individuals from three unrelated families with Blau syndrome. A complex ophthalmic and general health examination including diagnostic imaging was performed. The NOD2 mutational hot spot located in exon 4 was Sanger sequenced in all three probands. Two individuals also underwent autoinflammatory disorder gene panel screening, and in one subject, exome sequencing was performed. Blau syndrome presenting as uveitis, skin rush or arthritis was diagnosed in four cases from three families. In two individuals from one family, only camptodactyly was noted, while another member had camptodactyly in combination with non-active uveitis and angioid streaks. One proband developed two attacks of meningoencephalitis attributed to presumed neurosarcoidosis, which is a rare finding in Blau syndrome. The probands from families 1 and 2 carried pathogenic variants in NOD2 (NM_022162.3): c.1001G>A p.(Arg334Gln) and c.1000C>T p.(Arg334Trp), respectively. In family 3, two variants of unknown significance in a heterozygous state were found: c.1412G>T p.(Arg471Leu) in NOD2 and c.928C>T p.(Arg310*) in NLRC4 (NM_001199139.1). In conclusion, Blau syndrome is a phenotypically highly variable, and there is a need to raise awareness about all clinical manifestations, including neurosarcoidosis. Variants of unknown significance pose a significant challenge regarding their contribution to etiopathogenesis of autoinflammatory diseases.

A case of renal sarcoidosis complicated by parotid gland and uterine lesions

BACKGROUND

Sarcoidosis is a systemic disease that can affect multiple organs. While pulmonary sarcoidosis is most commonly observed, renal sarcoidosis occurs less frequently. We herein report a case of sarcoidosis with an exceptionally rare distribution including renal lesions.

CASE PRESENTATION

A 51-year-old Japanese female was referred because of bilateral parotid swelling and renal dysfunction. Computed tomography scan showed the swelling of bilateral kidneys, parotid glands, and uterus. Ga scintigraphy also showed remarkable accumulation in these organs. Renal biopsy and cytological evaluations of parotid gland and uterus were performed and she was diagnosed as sarcoidosis of these organs. Treatment was initiated with prednisolone 40 mg/day and then renal dysfunction subsequently improved. In addition, the swelling of parotid glands and uterus improved and Ga accumulation in each organ had disappeared.

CONCLUSION

This is a first case of renal sarcoidosis complicated by parotid glands and uterus lesions. Pathological findings and the reactivity observed in Ga scintigraphy indicated the presence of lesions in these organs.

High-Risk Sarcoidosis: A Focus on Pulmonary, Cardiac, Hepatic and Renal Advanced Diseases, as Well as on Calcium Metabolism Abnormalities

Although sarcoidosis is generally regarded as a benign condition, approximately 20-30% of patients will develop a chronic and progressive disease. Advanced pulmonary fibrotic sarcoidosis and cardiac involvement are the main contributors to sarcoidosis morbidity and mortality, with failure of the liver and/or kidneys representing additional life-threatening situations. In this review, we discuss diagnosis and treatment of each of these complications and highlight how the integration of clinical, pathological and radiological features may help predict the development of such high-risk situations in sarcoid patients.

Predictive role of natural killer cells in bronchoalveolar lavage fluid of patients with sarcoidosis

Sarcoidosis is a rare granulomatous disease of unknown aetiology belonging to the wide group of interstitial lung diseases.). Although the limitlessness of BAL fluid is debated, it remains one of the best matrices for studying the pathogenesis of sarcoidosis. Natural killer (NK) cells have been described in BAL fluid from sarcoidosis patients. Elevated NK cells in BAL fluid from sarcoidosis patients have been found to be associated with poor outcomes. In this study, NK cells were evaluated in BAL samples from sarcoidosis patients at the time of diagnosis and associated with clinical characteristics in order to evaluate their prognostic role. Of the 276 patients suspected to have sarcoidosis on the basis of clinical and radiological findings, 248 had a final diagnosis of sarcoidosis. Clinical parameters, Scadding stage, and extrapulmonary localization were collected in a database. It resulted in fibrotic sarcoidosis patients being associated with an increase in lymphocyte percentages in BAL samples, particularly NK cells when compared with other groups. From ROC analysis, NK cell percentages in BAL samples resulted as being the best predictive markers in discriminating stage 4 of sarcoidosis from other RX stages (AUC=0.85, p<0.0001). Furthermore, after the stratification of patients on the basis of the number of extrapulmonary localizations, patients with an higher number of extrapulmonary localizations also showed higher percentages of NK cells in BAL fluid. In conclusion, NK cell percentages in BAL fluid can be considered a good prognostic marker of fibrotic phenotypes of sarcoidosis and involvement of other organs, although their diagnostic utility was poor.

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.

Re-evaluating serum angiotensin-converting enzyme in sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology, which mainly affects the lungs and lymph nodes, as well as extrapulmonary organs. Its incidence, and prevalence rate, and disease course largely vary with regions and populations globally. The clinical manifestations of sarcoidosis depend on the affected organs and the degree of severity, and the diagnosis is mainly based on serum biomarkers, radiographic, magnetic resonance, or positron emission tomography imaging, and pathological biopsy. Noncaseating granulomas composing T cells, macrophages, epithelioid cells, and giant cells, were observed in a pathological biopsy, which was the characteristic pathological manifestation of sarcoidosis. Angiotensin-converting enzyme (ACE) was first found in the renin-angiotensin-aldosterone system. Its main function is to convert angiotensin I (Ang I) into Ang II, which plays an important role in regulating blood pressure. Also, an ACE insertion/deletion polymorphism exists in the human genome, which is involved in the occurrence and development of many diseases, including hypertension, heart failure, and sarcoidosis. The serum ACE level, most commonly used as a biomarker in diagnosing sarcoidosis, in patients with sarcoidosis increases. because of epithelioid cells and giant cells of sarcoid granuloma expressing ACE. Thus, it serves as the most commonly used biomarker in the diagnosis of sarcoidosis and also aids in analyzing its therapeutic effect and prognosis in patients with sarcoidosis.

Pulmonary fibrosis in sarcoidosis

Sarcoidosis may progress to pulmonary fibrosis in 5% of patients with significantly increased mortality. Histopathology shows fibrosis in a lymphangitic pattern surrounding the granulomas. Th1 to Th2 shift in environment along with angiogenesis is implicated in exuberant fibrosis. Clinical features include dyspnea, cough, and frequently with pulmonary function tests showing a mixed ventilatory defect with severely decreased diffusion capacity of carbon monoxide.  Serologic markers including soluble interleukin 2 receptor, chitotriosidase and kern von den lunges 6, and chemokine ligand 18 are elevated and implicated in progression of disease. CT imaging shows fibrosis along bronchovascular bundles with reticulations, traction bronchiectasis and honeycombing predominantly in the upper and central distribution. Complications include sarcoidosis-associated pulmonary hypertension (SAPH) and chronic pulmonary aspergillosis. Treatment involves glucocorticoids and steroid-sparing agents in the presence of active granulomas. Anti-fibrotic agents such as pirfenidone and nintedanib have been shown to slow down pulmonary function decline in randomized clinical trials involving sarcoidosis-associated pulmonary fibrosis. Transplant workup is indicated in New York Heart Association class III or IV with similar success rates as in other lung transplant patients.

The Relationship Between Serum Angiotensin Converting Enzyme Level and the Decision to Escalate Treatment of Sarcoidosis

PURPOSE

We performed a retrospective analysis of a sarcoidosis cohort who had sACE obtained at their initial clinic visit, but the treating physician was blinded to the results. We examined the relationship between sACE and the treating physician's decision to escalate sarcoidosis treatment.

METHODS

Treatment was considered escalated if the prednisone dose was increased or if the prednisone dose was not changed but an additional anti-sarcoidosis drug was added or the dose was increased.

RESULTS

561 sarcoidosis patients were analyzed. The most common target organ was the lung (84%). Using a cut-off of > 82 units/L for an elevated sACE, 31/82 (38%) with an elevated sACE had treatment escalation whereas 91/497 (18%) had treatment escalation with a normal sACE (p < 0.0001). For the need of treatment escalation, a sACE (cut-off of > 82) had sensitivity 0.25, specificity 0.89, positive predictive value 0.38, negative predictive value 0.81. These results were not appreciably different using other sACE cut-off values such as 70, 80, 90, or 100. A multivariable logistic regression model that included demographics, the target organ, spirometry results estimated that sACE level and lower FVC were significantly associated with the likelihood of treatment escalation. These findings held when sACE > 82 replaced sACE level in the multivariable logistic regression model.

CONCLUSIONS

Although there was a strong correlation between sACE at the initial sarcoidosis clinic visit and subsequent treatment escalation of sarcoidosis, the predictive power was such that sACE is not adequately reliable to be used in isolation to make this determination.

Correlation of the High-Resolution Computed Tomography Patterns of Intrathoracic Sarcoidosis with Serum Levels of SAA, CA 15.3, SP-D, and Other Biomarkers of Interstitial Lung Disease

Studies on the serum biomarkers of granulomatous inflammation and pulmonary interstitial disease in intrathoracic sarcoidosis have shown conflicting results. We postulated that differences in the concentrations of serum biomarkers can be explained by the heterogenous patterns of sarcoidosis seen on thoracic HRCT. Serum biomarker levels in 79 consecutive patients, newly diagnosed with intrathoracic sarcoidosis, were compared to our control group of 56 healthy blood donors. An analysis was performed with respect to HRCT characteristics (the presence of lymph node enlargement, perilymphatic or peribronchovascular infiltrates, ground-glass lesions, or fibrosis), CXR, and disease extent. Serum levels of CXCL9, CXCL10, CTO, and CCL18 were statistically significantly increased in all patients compared to controls. Serum levels of CA15.3 were statistically significantly increased in all patients with parenchymal involvement. SAA was increased in patients with ground-glass lesions while SP-D levels were statistically significantly increased in patients with lung fibrosis. Only SP-D and CA15.3 showed a significant correlation to interstitial disease extent. In conclusion, we found that sarcoidosis patients with different HRCT patterns of intrathoracic sarcoidosis have underlying biochemical differences in their serum biomarkers transcending Scadding stages. The stratification of patients based on both radiologic and biochemical characteristics could enable more homogenous patient selection for further prognostic studies.

Lymphocyte Subsets and Pulmonary Nodules to Predict the Progression of Sarcoidosis

The search for biological markers, which allow a relatively accurate assessment of the individual course of pulmonary sarcoidosis at the time of diagnosis, remains one of the research priorities in this field of pulmonary medicine. The aim of our study was to investigate possible prognostic factors for pulmonary sarcoidosis with a special focus on cellular immune inflammation markers. A 2-year follow-up of the study population after the initial prospective and simultaneous analysis of lymphocyte activation markers expression in the blood, as well as bronchoalveolar lavage fluid (BALF) and lung biopsy tissue of patients with newly diagnosed pulmonary sarcoidosis, was performed. We found that some blood and BAL fluid immunological markers and lung computed tomography (CT) patterns have been associated with a different course of sarcoidosis. We revealed five markers that had a significant negative association with the course of sarcoidosis (worsening pulmonary function tests and/or the chest CT changes)-blood CD4+CD31+ and CD4+CD44+ T lymphocytes, BALF CD8+CD31+ and CD8+CD103+ T lymphocytes and a number of lung nodules on chest CT at the time of the diagnosis. Cut-off values, sensitivity, specificity and odds ratio for predictors of sarcoidosis progression were calculated. These markers may be reasonable predictors of sarcoidosis progression.

Sarcoidosis-Related Uveitis: A Review

Sarcoidosis is an inflammatory disease that involves the eyes in 10-55% of cases, sometimes without systemic involvement. All eye structures can be affected, but uveitis is the most common ocular manifestation and causes vision loss. The typical ophthalmological appearance of these uveitis is granulomatous (in cases with anterior involvement), which are usually bilateral and with synechiae. Posterior involvement includes vitritis, vasculitis and choroidal lesions. Tuberculosis is a classic differential diagnosis to be wary of, especially in people who have spent time in endemic areas. The diagnosis is based on histology with the presence of non-caseating epithelioid granulomas. However, due to the technical difficulty and yield of biopsies, the diagnosis of ocular sarcoidosis is often based on clinico-radiological features. The international criteria for the diagnosis of ocular sarcoidosis have recently been revised. Corticosteroids remain the first-line treatment for sarcoidosis, but up to 30% of patients require high doses, justifying the use of corticosteroid-sparing treatments. In these cases, immunosuppressive treatments such as methotrexate may be introduced. More recent biotherapies such as anti-TNF are also very effective (as they are in other non-infectious uveitis etiologies).

The Effect of an Essential Oil Blend on Growth Performance, Intestinal Health, and Microbiota in Early-Weaned Piglets

Essential oils (EO) are promising feed additives for their antibacterial, antioxidant, and immune-enhancing abilities with low toxicity. Carvacrol, thymol, and cinnamaldehyde are commonly used to synthesize EO. However, few studies focus on combining these three EO in early-weaned piglets. In the present study, 24 piglets weaned at 21 d of age were randomly divided into 2 groups (6 replicate pens per group, 2 piglets per pen). The piglets were fed a basal diet (the control group) and a basal diet supplemented with 400 mg/kg EO (a blend consisting of carvacrol, thymol, and cinnamaldehyde, the EO group) for 28 days. At the end of the experiment, one piglet per pen was randomly chosen to be sacrificed. Growth performance, hematology, plasma biochemical indices, antioxidant capacity, intestinal epithelial development and immunity, colonic volatile fatty acids (VFA), and microbiota were determined. The results indicated that the diet supplemented with EO significantly improved average daily feed intake (ADFI, p < 0.01) and average daily gain (ADG, p < 0.05) in the day 0 to 28 period. EO supplementation led to a significant decrease in plasma lysozyme (p < 0.05) and cortisol levels (p < 0.01). Additionally, EO significantly promoted jejunal goblet cells in the villus, jejunal mucosa ZO-1 mRNA expression, ileal villus height, and ileal villus height/crypt depth ratio in piglets (p < 0.05). The ileal mucosal TLR4 and NFκB p-p65/p65 protein expression were significantly inhibited in the EO group (p < 0.05). Colonic digesta microbiota analysis revealed that bacteria involving the Erysipelotrichaceae family, Holdemanella genus, Phascolarctobacterium genus, and Vibrio genus were enriched in the EO group. In conclusion, these findings indicate that the EO blend improves ADG and ADFI in the day 0 to 28 period, as well as intestinal epithelial development and intestinal immunity in early-weaned piglets, which provides a theoretical basis for the combined use of EO in weaned piglets.

Sarcoidosis: Progression to the chronic stage and pathogenic based treatment (narrative review)

Many factors confirm the autoimmune nature of sarcoidosis and help in determining the strategy of patient management and treatment initiation. However, the causes and the mechanisms of disease progression that result in fibrosis and insufficiency of the affected organ remain unclear. This narrative review aims to analyse the mechanisms and biomarkers of sarcoidosis progression, as well as the pathogenetic basis of sarcoidosis therapy. The following characteristics of progressive chronic sarcoidosis were revealed: the disease develops in patients with a genetic predisposition (SNP in genes GREM1, CARD15, TGF-β3, HLA-DQB1^*06:02, HLA-DRB1^*07/14/15), which contributes either the decreased ability of antigen elimination or autoimmune inflammation. Various prognostic biomarkers of disease progression (decreased levels of neopterin, elastase, sIL-2R, chitotriosidase, glycoprotein Krebs von den Lungen, Th17 cell count, reduced quantity of TNF-α in peripheral blood or bronchoalveolar lavage fluid) have been described and can potentially be used to determine the group of patients who will benefit from the use of corticosteroids/cytostatic drugs/biologics.

Longitudinal and Comparative Measures of Serum Chitotriosidase and YKL-40 in Patients With Idiopathic Pulmonary Fibrosis

Background

Although chitin is absent in humans, chitinases are present in healthy subjects and show dysregulated expression in a variety of diseases resulting from abnormal tissue injury and repair responses. It was shown that chitotriosidase (chitinase 1/CHIT1) and structurally-related chitinase 3-like 1 protein (CHI3L1/YKL-40) play important roles in the pathobiology of idiopathic pulmonary fibrosis (IPF), however little is known about their longitudinal serum levels and relationship to clinical measures in IPF.

Methods

The present study is the first to evaluate serial measurements of serum CHIT1 activity and YKL-40 concentrations in patients with IPF starting antifibrotic treatment and followed up for 24 months. In addition, baseline serum CHIT1 and YKL-40 were compared between patients with IPF and control subjects, and possible CHIT1 and YKL-40 relationships to longitudinal clinical assessments in IPF were explored.

Results

Baseline serum CHIT1 activity and YKL-40 concentrations were significantly elevated in patients with IPF compared to control subjects and showed similar discriminatory ability in distinguishing IPF from controls. No significant differences between the median serum CHIT1 activity and YKL-40 concentration measured over a study follow-up were noted. We found significantly elevated baseline serum CHIT1 activity in the progressors compared with the stables in the first year, while significantly increased baseline serum CHIT1 activity was noted in the stables compared to the progressors in the second year. Additionally, we observed a significant negative correlation between a change in serum YKL-40 concentration and a change in forced vital capacity (FVC) % predicted (% pred.) in the stables subgroup, whereas, a change in serum CHIT1 activity correlated negatively with a change in FVC% pred. in the progressors subgroup.

Conclusions

This explorative study findings add further evidence that CHIT1 and YKL-40 are upregulated in patients with IPF, and suggest that longitudinally stable serum CHIT1 activity and YKL-40 concentration levels may potentially be associated with the antifibrotic treatment response. In addition, our findings are supporting the possible role of CHIT1 and YKL-40 as candidate diagnostic and prognostic biomarkers in IPF. Further research is needed to validate present study findings.

Progress in the diagnosis of ocular sarcoidosis

Sarcoidosis is a multisystem granulomatous inflammation that affects multiple organ systems. The spectrum of extraocular and ocular involvement is wide and may precede systemic involvement. The diagnosis of ocular sarcoidosis relies on a combination of clinical findings, laboratory investigations, and radiographic findings. These include but are not limited to serum angiotensin-converting enzyme (ACE), lysozyme, plain-film radiographs of the chest, computed tomography (CT) scans of the chest, pulmonary function testing, bronchoalveolar lavage, and retinal imaging among others. In this review, we highlight current and evolving systemic investigations and approaches to ophthalmic imaging when considering the diagnosis of ocular sarcoidosis.

Krebs von den Lungen-6 as Disease Severity Marker for COVID-19 Patients: Analytical Verification and Quality Assessment of the Tosoh AIA-360 Compared to Lumipulse G600II

Background: Krebs von den Lungen-6 (KL-6) has been proposed as a disease severity marker of COVID-19. All research articles reported the KL-6 assay detected through Fujirebio reagents by Lumipulse G600/G1200 instrument. In the present study, KL-6 assay was analysed through Tosoh AIA-360 and compared with analytical results by Lumipulse G600 in a population of COVID-19 patients. Materials and methods: Sixty-four patients (median age, IQR 67 (58–76) years), all hospitalized for COVID-19 interstitial pneumonia at Siena COVID Unit. KL-6 was measured by two methods, chemiluminescence enzyme immunoassay (CLEIA) and fluorescent enzyme immunoassay (FEIA) method by Lumipulse G600 II and AIA 360 systems, respectively. Results: KL-6 concentrations evaluated by Lumipulse G600II were significantly higher in severe than those in non-severe patients (p < 0.0001) as well as evaluating by AIA360 (p < 0.0001). Receiver operating curve (ROC) curve analysis showed that KL-6 concentrations, by Lumipuse G600II, distinguished severe from non-severe COVID-19 patients with an area under the curve (AUC) of 99.8% and the best cut-off value was 448 U/mL. AUROC between severe and non-severe COVID-19 patients using T0 KL-6 concentrations by AIA360 was 97.4% and the best cut-off value was 398 U/mL. According to T0 KL-6 concentrations in COVID-19 patients, Bland–Altman difference analysis revealed a mean bias of 78 ± 174.8; while using T1 KL-6 concentrations in COVID-19 patients, Bland–Altman difference analysis revealed a mean bias of 48 ± 126 (95% limits of agreement −199–295) between the Lumipulse G600 II and the AIA360 systems. Conclusions: In conclusion, our study demonstrated that CLEIA and FEIA methods for serum KL-6 detection are comparable and reliable. KL-6 was confirmed as an easily detectable and effective biomarker to identify severe COVID-19 patients.

Granulomatous Diseases of the Central Nervous System

PURPOSE OF REVIEW

To discuss the pathophysiology, key clinical features, necessary diagnostic evaluation, and current treatment regimens for granulomatous diseases of the central nervous system.

RECENT FINDINGS

The diagnosis and management of granulomatous disease of the central nervous system has been revolutionized by advances in diagnostic imaging. Nevertheless, tissue and/or cerebrospinal fluid (CSF) sampling remains necessary to establish the diagnosis in most cases. Establishing a specific diagnosis is critical because treatment selection needs to focus on the granulomatous process centering on either antibiotic or immunosuppressive agents. Particular for non-infectious granulomatous disease more aggressive immunotherapies may help in clinical outcome. There are multiple non-infectious and infectious etiologies for granulomatous disease of the central nervous system. Clinical manifestations result from local structural invasion of granulomas or granulomatous inflammation of the blood vessels and meninges. Rapid diagnosis and specific treatment is essential.

Transcriptomics of bronchoalveolar lavage cells identifies new molecular endotypes of sarcoidosis

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease of unknown origin with a variable and often unpredictable course and pattern of organ involvement. In this study we sought to identify specific bronchoalveolar lavage (BAL) cell gene expression patterns indicative of distinct disease phenotypic traits.

METHODS

RNA sequencing by Ion Torrent Proton was performed on BAL cells obtained from 215 well-characterised patients with pulmonary sarcoidosis enrolled in the multicentre Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS) study. Weighted gene co-expression network analysis and nonparametric statistics were used to analyse genome-wide BAL transcriptome. Validation of results was performed using a microarray expression dataset of an independent sarcoidosis cohort (Freiburg, Germany; n=50).

RESULTS

Our supervised analysis found associations between distinct transcriptional programmes and major pulmonary phenotypic manifestations of sarcoidosis including T-helper type 1 (Th1) and Th17 pathways associated with hilar lymphadenopathy, transforming growth factor-β1 (TGFB1) and mechanistic target of rapamycin (MTOR) signalling with parenchymal involvement, and interleukin (IL)-7 and IL-2 with airway involvement. Our unsupervised analysis revealed gene modules that uncovered four potential sarcoidosis endotypes including hilar lymphadenopathy with increased acute T-cell immune response; extraocular organ involvement with PI3K activation pathways; chronic and multiorgan disease with increased immune response pathways; and multiorgan involvement, with increased IL-1 and IL-18 immune and inflammatory responses. We validated the occurrence of these endotypes using gene expression, pulmonary function tests and cell differentials from Freiburg.

CONCLUSION

Taken together, our results identify BAL gene expression programmes that characterise major pulmonary sarcoidosis phenotypes and suggest the presence of distinct disease molecular endotypes.

The Use of Chitotriosidase as a Marker of Active Sarcoidosis and in the Diagnosis of Fever of Unknown Origin (FUO)

Sarcoidosis is a multi-organ inflammatory granulomatosis with a lung-predominant involvement. The aim of this study was to investigate the use of serum chitotriosidase (CHIT1) in patients with fever of unknown origin (FUO); the patients with confirmed diagnosis of active sarcoidosis were compared with ones affected by inactive or treated sarcoidosis. CHIT1 activity was evaluated in 110 patients initially admitted at the hospital as FUOs. The overall performance of CHIT1 for active sarcoidosis diagnosis was assessed by performing an area under the receiver operating characteristic curve analysis (AUROC). The sarcoidosis patients were significantly older than the FUO patients not affected by sarcoidosis (p < 0.01). CHIT1 showed a good accuracy as a biomarker for active sarcoidosis in patients explored for FUO (AUROC 0.955; CI 95% 0.895–0.986; p < 0.001). A CHIT1 value >90.86 showed 96.8% sensitivity (84.2–99.9) and 85.5% specificity (75–92.8) in discriminating active sarcoidosis from other causes of FUO. CHIT1 significantly discriminated active versus inactive/under treatment sarcoidosis patients (with lower enzyme activity) (ROC analysis, sensitivity: 96.9%, specificity: 94.7%, value >83.01 nmol/mL/h, AUROC: 0.958, 0.862–0.994, p < 0.001) compared to ACE (ROC analysis, sensitivity: 25.8%, specificity: 93.7%, value >65 UI/L). In conclusion, CHIT1 is a reliable/sensitive biomarker of active sarcoidosis, with values significantly decreasing in remitted/treated patients. It significantly discriminates active sarcoidosis from FUO patients, providing a useful tool in the diagnosis-assessing process.

Renal involvement in sarcoidosis: histological patterns and prognosis, an Italian survey

Background

Granulomatous interstitial nephritis in sarcoidosis (sGIN) is generally clinically silent, but in <1% causes acute kidney injury (AKI).

Methods

This Italian multicentric retrospective study included 39 sarcoidosis-patients with renal involvement at renal biopsy: 31 sGIN-AKI, 5 with other patterns (No-sGIN-AKI), 3 with nephrotic proteinuria. We investigate the predictive value of clinical features, laboratory, radiological parameters and histological patterns regarding steroid response. Primary endpoint: incident chronic kidney disease (CKD) beyond the 1°follow-up (FU) year; secondary endpoint: response at 1°line steroid therapy; combined endpoint: the association of initial steroid response and outcome at the end of FU.

Results

Complete recovery in all 5 No-sGIN-AKI-patients, only in 45% (13/29) sGIN-AKI-patients (p=0.046) (one lost in follow-up, for another not available renal function after steroids). Nobody had not response. Primary endpoint of 22 sGIN-AKI subjects: 65% (13/20) starting with normal renal function developed CKD (2/22 had basal CKD; median FU 77 months, 15-300). Combined endpoint: 29% (6/21) had complete recovery and final normal renal function (one with renal relapse), 48% (10/21) had partial recovery and final CKD (3 with renal relapse, of whom one with basal CKD) (p=0.024). Acute onset and hypercalcaemia were associated to milder AKI and better recovery than subacute onset and patients without hypercalcaemia, women had better endpoints than men. Giant cells, severe interstitial infiltrate and interstitial fibrosis seemed negative predictors in terms of endpoints.

Conclusions

sGIN-AKI-patients with no complete recovery at 1°line steroid should be treated with other immunosuppressive to avoid CKD, in particular if males with subacute onset and III stage-not hypercalcaemic AKI.

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.

Prognostic role of KL-6 in SSc-ILD patients with pleuroparenchymal fibroelastosis

BACKGROUND

Krebs von den Lungen-6 (KL-6) is a high-molecular-weight (200kDa) glycoprotein proposed as a diagnostic biomarker for differentiating interstitial lung disease (ILD). Systemic sclerosis (SSc) is a rare immune-mediated disorder, and ILD is the leading cause of morbidity and mortality. Pleuroparenchymal fibroelastosis (PPFE) has been described to have a poor prognosis in SSc-ILD patients. This study undertook to compare serial changes in KL-6 in SSc-ILD patients with and without PPFE, to verify its prognostic value as a disease biomarker.

MATERIALS AND METHODS

Twenty-five SSc-ILD patients (median IQR, 62 (56-58); 20% males) were retrospectively enrolled. 12 SSc-ILD patients (48%) had also a radiological diagnosis of PPFE. Serum KL-6 concentrations were measured by KL-6 reagent assay (Fujirebio Europe, Ghent, Belgium).

RESULTS

Serum KL-6 measurements were increased in SSc-ILD patients with and without PPFE compared with healthy controls (P < .0001). Comparative analysis of the rate of variation of KL-6 over the 6 years of follow-up was performed by serial two-yearly KL-6 measurements: Δ1(t1-t0), Δ2(t2-t1) and Δ3(t3-t2). In SSc-ILD patients with PPFE pattern, Δ3 was significantly different than those without PPFE pattern (P = .0020). Serum KL-6 levels were significantly different (P = .0455) either at Δ2 and Δ3 in the PPFE group. In SSc-ILD patients with PPFE, at t3 serum KL-6 concentrations were inversely correlated with FEV1 (r = -.76; P = .037) and FVC percentages (r = -.79; P = .028).

CONCLUSION

These results suggest that serial measurements of KL-6 in the follow-up of these patients may help to monitor disease progression. In real life, in SSc-ILD patients PPFE should be always evaluated at CT and when present should suggest a tight follow-up to monitor its evolution.

Clinical phenotyping in sarcoidosis management

Sarcoidosis is a heterogeneous granulomatous disease. Biological markers and clinical features could allow specific phenotypes to be associated with different prognosis, severity and treatment responses. This retrospective multicentre study aims to analyse the clinical and immunological features of sarcoidosis and to identify a routine non-invasive biomarker useful in clinical practice.

CD31+, CD38+, CD44+, and CD103+ lymphocytes in peripheral blood, bronchoalveolar lavage fluid and lung biopsy tissue in sarcoid patients and controls

Background

The mechanisms driving the transition from inflammation to fibrosis in sarcoidosis patients are poorly understood; prognostic features are lacking. Immune cell profiling may provide insights into pathogenesis and prognostic factors of the disease. This study aimed to establish associations in simultaneous of lymphocyte subset profiles in the blood, bronchoalveolar lavage fluid (BALF), and lung biopsy tissue in the patients with newly diagnosed sarcoidosis.

Methods

A total of 71 sarcoid patients (SPs) and 20 healthy controls (HCs) were enrolled into the study. CD31, CD38, CD44, CD103 positive T lymphocytes in blood and BALF were analysed. Additionally, the densities of CD4, CD8, CD38, CD44, CD103 positive cells in lung tissue biopsies were estimated by digital image analysis.

Results

Main findings: (I) increase of percentage of CD3⁺CD4⁺CD38⁺ in BALF and blood, and increase of percentage of CD3⁺CD4⁺CD44⁺ in BALF in Löfgren syndrome patients comparing with patients without Löfgren syndrome, (II) increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in patients without Löfgren syndrome (comparing with Löfgren syndrome patients) and increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in more advanced sarcoidosis stage. (III) Increasing percentage of BALF CD3⁺CD4⁺CD31⁺ in sarcoidosis patients when comparing with controls independently of presence of Löfgren syndrome, smoking status or stage of sarcoidosis. Several significant correlations were found.

Conclusions

Lymphocyte subpopulations in blood, BALF, and lung tissue were substantially different in SPs at the time of diagnosis compared to HCs. CD3⁺CD4⁺CD31⁺ in BALF might be a potential supporting marker for the diagnosis of sarcoidosis. CD3⁺CD4⁺CD38⁺ in BALF and blood and CD3⁺CD4⁺CD44⁺ in BALF may be markers of the acute immune response in sarcoidosis patients. CD4⁺CD103⁺ T-cells in BALF and in blood are markers of the persistent immune response in sarcoidosis patients and are potential prognostic features of the chronic course of this disease.

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.

Club Cell Secreted Protein CC16: Potential Applications in Prognosis and Therapy for Pulmonary Diseases

Club cell secretory protein (CC16) is encoded by the SCGB1A1 gene. It is also known as CC10, secretoglobin, or uteroglobin. CC16 is a 16 kDa homodimeric protein secreted primarily by the non-ciliated bronchial epithelial cells, which can be detected in the airways, circulation, sputum, nasal fluid, and urine. The biological activities of CC16 and its pathways have not been completely understood, but many studies suggest that CC16 has anti-inflammatory and anti-oxidative effects. The human CC16 gene is located on chromosome 11, p12-q13, where several regulatory genes of allergy and inflammation exist. Studies reveal that factors such as gender, age, obesity, renal function, diurnal variation, and exercise regulate CC16 levels in circulation. Current findings indicate CC16 not only may reflect the pathogenesis of pulmonary diseases, but also could serve as a potential biomarker in several lung diseases and a promising treatment for chronic obstructive pulmonary disease (COPD). In this review, we summarize our current understanding of CC16 in pulmonary diseases.

Propionibacterium acnes-associated sarcoidosis complicated by acute bird-related hypersensitivity pneumonitis

Background

The number of reports on sarcoidosis complicated by hypersensitivity pneumonitis (HP) is limited, and most describe cases complicated by chronic bird-related HP. Here, we present for the first time a case with Propionibacterium acnes-associated sarcoidosis complicated by acute bird-related HP.

Case presentation

A 62-year-old man with a past medical history of sarcoidosis was admitted to our department, and chest computed tomography showed diffuse ground-glass opacities, which appeared as he rapidly increased the number of pigeons he kept for a competition. Random transbronchial lung biopsy revealed well-formed non-caseating epithelioid granulomas, which contained positively stained substances on immunohistochemistry using the PAB antibody, a specific monoclonal antibody against P. acnes lipoteichoic acid. Poorly formed non-caseating granulomas without positively stained substances were also detected.

Conclusion

We describe the successful identification of this exceptionally rare case of sarcoidosis complicated by acute bird-related HP in which two morphologically and immunohistologically different types of granulomas were present in the same lung.

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.

Utility of serological biomarker' panels for diagnostic accuracy of interstitial lung diseases

Interstitial lung diseases (ILD) are a heterogeneous group of illnesses of known and unknown aetiology. Differential diagnosis among the three disorders is often challenging. Specific biomarkers with good sensitivity and specificity are therefore needed to predict clinical outcome and guide clinical decisions. The aim of this study was to investigate inflammatory/fibrotic biomarkers, to determine whether single mediators or panels of mediators could be useful to stratify patients into three distinct domains: sarcoidosis, idiopathic pulmonary fibrosis (IPF) and chronic hypersensitivity pneumonitis (cHP). A total of 163 ILD patients monitored at Siena Referral Centre for Sarcoidosis and other Interstitial Lung Diseases were enrolled in the study. Clinical data, pulmonary function tests and biochemical analytes were retrospectively collected. SAA levels were detected by ELISA kit and Krebs von den Lungen 6 (KL-6) were measured by CLEIA method, for sarcoidosis, cHP and IPF patients. Multiple comparison analysis showed significant differences in C reactive protein (CRP), white blood cell count (WBC) and creatinine levels between the three groups. In the logistic regression model, KL-6, CRP and WBC showed areas under curves (AUC) 0.86, for sarcoidosis diagnosis. The logistic regression model KL-6 and SAA showed the best performance with an AUC 0.81 for discriminating IPF than cHP and sarcoidosis. For differential diagnosis of IPF and cHP, KL-6 and SAA were considered in the logistic regression model, showed an AUC 0.79. The combination of serum biomarkers proposed here offers insights into the pathobiology of ILDs. These panels of bioindicators will improve diagnostic accuracy and will be useful in the clinical management of ILDs.

Key Players and Biomarkers of the Adaptive Immune System in the Pathogenesis of Sarcoidosis

Sarcoidosis is a systemic inflammatory disease characterized by development of granulomas in the affected organs. Sarcoidosis is often a diagnosis of exclusion, and traditionally used tests for sarcoidosis demonstrate low sensitivity and specificity. We propose that accuracy of diagnosis can be improved if biomarkers of altered lymphocyte populations and levels of signaling molecules involved in disease pathogenesis are measured for patterns suggestive of sarcoidosis. These distinctive biomarkers can also be used to determine disease progression, predict prognosis, and make treatment decisions. Many subsets of T lymphocytes, including CD8⁺ T-cells and regulatory T-cells, have been shown to be dysfunctional in sarcoidosis, and the predominant CD4⁺ T helper cell subset in granulomas appears to be a strong indicator of disease phenotype and outcome. Studies of altered B cell populations, B cell signaling molecules, and immune complexes in sarcoidosis patients reveal promising biomarkers as well as possible explanations of disease etiology. Furthermore, examined biomarkers raise questions about new treatment methods and sarcoidosis antigens.

Bronchoalveolar lavage and serum KL-6 concentrations in chronic hypersensitivity pneumonitis: correlations with radiological and immunological features

Chronic hypersensitivity pneumonitis (cHP) is a fibrotic interstitial lung disease (ILD) resulting from inhalation of different organic substances and chemical compounds determining an inflammatory and immunological response in sensitized individuals. KL-6, a human mucin protein expressed by type 2 pneumocytes, has been proposed as a prognostic biomarker of cHP. Assessment of usefulness KL-6 in ILD has been investigated primarily in Asiatic population. The aim of this study was to evaluate clinical utility of KL-6 in serum and bronchoalveolar lavage (BAL). In this study, we retrospectively analysed clinical, radiological and immunological data of a cohort of 42 patients affected by cHP: KL-6 concentrations were collected from serum and BAL. KL-6 clinical value was assessed through the analysis of association between KL-6 concentrations and clinical, functional, immunological and radiological features. KL-6 serum concentration results increased in 28/34 patients (82%). A positive direct correlation was observed between KL-6 concentrations in BAL and serum (r = 0.62, p < 0.05). In our study population we found that patients with extensive presence of ground glass opacities and centrilobular nodules at high-resolution computed tomography (HRCT) showed the highest concentrations of KL-6 in BAL and a predominantly CD3+ CD8+ BAL lymphocytosis. BAL lymphocytosis and KL-6 concentrations showed a direct correlation. BAL KL-6, a result of alveolar damage, caused in cHP by CD3+ CD8+ mediated flogosis and suggested by radiological evidence of ground-glass opacities and centrilobular nodules, can be considered a useful biomarker to assess, along with BAL cellular analysis and HRCT findings, disease activity.

ERS International Congress, Madrid, 2019: highlights from the Interstitial Lung Diseases Assembly

This article discusses a selection of the scientific presentations in the field of interstitial lung diseases (ILDs) that took place at the 2019 European Respiratory Society International Congress in Madrid, Spain. There were sessions from all four groups within Assembly 12: group 12.01 "Idiopathic interstitial pneumonias", group 12.02 "ILDs/diffuse parenchymal lung diseases (DPLDs) of known origin", group 12.03 "Sarcoidosis and other granulomatous ILDs/DPLDs" and group 12.04 "Rare ILDs/DPLDs". The presented studies brought cutting-edge developments on several aspects of these conditions, including pathogenesis, diagnosis and treatment. As many of the ILDs are individually rare, the sharing of experiences and new data that occur during the Congress are very important for physicians interested in ILDs and ILD patients alike.

Serial investigation of Angiotensin-Converting Enzyme in sarcoidosis patients treated with Angiotensin-Converting Enzyme Inhibitor

BACKGROUND

Angiotensin-converting enzyme (ACE) is an acid glycoprotein that converts angiotensin I into angiotensin II. It is produced mainly by activated alveolar macrophages and it resulted elevated in sarcoidosis patients. ACE is the only biomarker mentioned in WASOG international guidelines for the diagnosis and follow-up of sarcoidosis patients but its sensitivity and specificity are low. This study aimed to analyze serial measurements of ACE levels in sarcoidosis patients stratified according to concomitant ACE-inhibitor therapies (ACEIs).

SUBJECTS AND METHODS

136 serum samples from sarcoidosis patients were retrospectively enrolled in the study. Serial ACE concentrations were measured once year for each patient. Population were divided according to radiogical stages and ACEIs.

RESULTS

ACE concentrations resulted higher in non-ACEIs than ACEIs group (p<E-04). This result was confirmed also stratifying population according to radiological stages particularly in stage 3 (p=2E-03) or stage 2 of the disease (p<1E-04). Considering ACEIs, serum ACE levels proved to be higher in sarcoidosis patients treated with zofenopril than in those treated with perindopril (p=2E-02), enalapril (p=2E-03) or ramipril (p=2E-04). Patients treated with ACEIs showed a progressive reduction in ACE levels to five years of follow-up (p=1.3E-02) and the zofenopril group recorded the highest ACE levels (p<1E-04).

CONCLUSIONS

This retrospective study investigated changes in ACE levels in patients with sarcoidosis treated or not treated with ACEIs. Considering the overall low sensitivity and specificity of this biomarker, we suggest systematically investigating medical drugs prescribed for patients with sarcoidosis, in order to optimize the interpretation of ACE in clinical management.

Personalized Approach of Severe Eosinophilic Asthma Patients Treated with Mepolizumab and Benralizumab

BACKGROUND

New anti-IL-5 antibodies, mepolizumab and benralizumab, have recently been approved for severe asthma, sharing the same inclusion criteria.

OBJECTIVE

To contribute on biomarkers research leading to the personalized choice, we investigated L-selectin, Krebs von den Lungen (KL-6), and lymphocyte subsets as bioindicators of airway hyper-responsiveness and remodeling.

MATERIALS AND METHODS

A cohort of 28 patients affected by severe eosinophilic asthma were treated with anti-IL-5 drugs. According to clinical parameters, patients were subdivided into early and partial responders. Lymphocytes subsets were analyzed through flow cytometry, while KL-6 and sL-selectin were analyzed on serum samples. Clinical, functional, and immunological data at baseline (T0), after 1 month (T1), and 6 months of therapy were collected in a database.

RESULTS

All treated patients showed an increase in the percentage of forced expiratory volume in the first second (FEV1) and FEV1/forced vital capacity ratio and a decrease of peripheral eosinophils for both drugs after 1 month of treatment. Mepolizumab-treated patients also showed decreased CD8+ and NKT-like cell percentages and a significant increase in sL-selectin concentrations between T0 and T1. Stratifying the cohort of our patients in early and partial responders at T0, they showed a reduction of peripheral eosinophils, sL-selectin and KL-6, while no differences were found at T0 between early and partial responders patients treated with benralizumab.

CONCLUSIONS

This real-life study provides new insights for the personalized approach to severe asthma therapy. Although preliminary, the results indicate that besides eosinophils, KL-6 and sL-selectin are useful as biomarkers of early response that can also involve in the pathogenesis of severe asthma.

Biomarkers in the Diagnosis and Prognosis of Sarcoidosis: Current Use and Future Prospects

Sarcoidosis is a heterogeneous disease in terms of presentation, duration, and severity. Due to this heterogeneity, it is difficult to align treatment decisions. Biomarkers have proved to be useful for the diagnosis and prognosis of many diseases, and over the years, many biomarkers have been proposed to facilitate diagnosis, prognosis, and treatment decisions. Unfortunately, the ideal biomarker for sarcoidosis has not yet been discovered. The most commonly used biomarkers are serum and bronchoalveolar lavage biomarkers, but these lack the necessary specificity and sensitivity. In sarcoidosis, therefore, a combination of these biomarkers is often used to establish a proper diagnosis or detect possible progression. Other potential biomarkers include imaging tools and cell signaling pathways. Fluor-18-deoxyglucose positron emission tomography and high-resolution computed tomography have been proven to be more sensitive for the diagnosis and prognosis of both pulmonary and cardiac sarcoidosis than the serum biomarkers ACE and sIL-2R. There is an upcoming role for exploration of signaling pathways in sarcoidosis pathogenesis. The JAK/STAT and mTOR pathways in particular have been investigated because of their role in granuloma formation. The activation of these signaling pathways also proved to be a specific biomarker for the prognosis of sarcoidosis. Furthermore, both imaging and cell signaling biomarkers also enable patients who might benefit from a particular type of treatment to be distinguished from those who will not. In conclusion, the diagnostic and prognostic path of sarcoidosis involves many different types of existing and new biomarker. Research addressing biomarkers and disease pathology is ongoing in order to find the ideal sensitive and specific biomarker for this disease.

Serum biomarker CA 15-3 as predictor of response to antifibrotic treatment and survival in idiopathic pulmonary fibrosis

Aim: Cancer antigen 15-3 (CA 15-3) is a baseline biomarker in idiopathic pulmonary fibrosis (IPF), but its value during follow-up is unknown. Materials and methods: Associations between serum CA 15-3 and pulmonary function tests during 1-year follow-up were evaluated by a mixed model in 132 IPF treated with pirfenidone or nintedanib. Results: Increased baseline (median: 56 kU/l) and follow-up CA 15-3 levels were inversely associated with forced vital capacity and diffusing capacity of the lung for carbon monoxide (estimates respectively: -5.21 and -4.69; p < 0.001). Baseline and 6-month CA 15-3 above 58.5 (hazard ratio: 1.67; p = 0.031) and 50.5 kU/l (hazard ratio: 2.99; p < 0.001), respectively, showed impaired survival compared with lower levels. Conclusion: CA 15-3 is associated with pulmonary function test during follow-up in IPF on antifibrotic treatment. Higher (follow-up) values are related with poor survival. Therefore, CA 15-3 is a promising follow-up biomarker in IPF.

Krebs von den Lungen-6 as a biomarker for disease severity assessment in interstitial lung disease: a comprehensive review

Aim: Interstitial lung diseases (ILD) are a group of lung disorders characterized by interstitial lung thickening. Krebs von den Lungen-6 (KL-6) is a molecule that is predominantly expressed by damaged alveolar type II cells and it has been proposed as a potential biomarker of different ILD. Materials & methods: A growing literature about KL-6 has been reviewed and selected to evaluate its role in the clinical management of ILD to predict disease diagnosis, activity, prognosis and treatment response. Results: KL-6 concentrations have been evaluated in fibrotic and granulomatous lung diseases and it was demonstrated to be a biomarker of disease severity useful for clinical follow-up of ILD patients. KL-6 levels differentiated between fibrotic ILD, such as idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis, and nonfibrotic lung disorders, including sarcoidosis and pulmonary alveolar proteinosis. Conclusion: KL-6 is predictive biomarker useful in the clinical management of ILD patients, in particular in patients with severe fibrotic lung disorders.

Neurosarcoidosis: clinical manifestations, investigation and treatment

Sarcoidosis affects the nervous system in 10% of cases. When it does so it can affect any part of the nervous system and with all degrees of severity. It forms part of the differential diagnosis in inflammatory, infective, neoplastic and degenerative neurological diseases and may be very difficult to diagnose without histological confirmation. Recent clinical studies and the increasing availability of new biological treatments allow a much clearer understanding of the disease. This review summarises its clinical features, imaging and laboratory characteristics, treatment and outcome.

Serum KL-6 levels in pulmonary Langerhans' cell histiocytosis

BACKGROUND

Serum Krebs von den Lungen-6 (sKL-6) is an high-molecular-weight (200 kDa) glycoprotein predominantly expressed by damaged alveolar type II cells, and it has been proposed as a potential biomarker of different ILD. This is a prognostic biomarker for chronic hypersensitivity pneumonitis (cHP) and idiopathic pulmonary fibrosis (IPF), two diseases that share several clinical and radiological features. Little data are available on the potential role of KL-6 in granulomatous and cystic interstitial lung diseases, including the orphan disease known as pulmonary Langerhans cell histiocytosis (PLCH).

METHODS

For the first time, sKL-6 concentrations were assayed and compared in 96 patients (17 PLCH, 22 IPF, 34 cHP) and 22 healthy controls.

RESULTS

Serum KL-6 concentrations were significantly higher in PLCH (599 ± 594 U/mL), IPF (1645 ± 846 U/mL) and cHP patients (1691 ± 1643 U/mL) than in healthy controls (268 U/mL) (P = .037). Area-under-the-curve values of sKL-6 were 73.4% between PLCH and healthy controls, 84.5% between IPF and PLCH and 78% between cHP and PLCH. An indirect correlation between sKL-6 concentrations and peripheral CD1a-positive cells was demonstrated (r = -0.82; P = .034).

CONCLUSION

Serum KL-6 concentrations were higher in PLCH patients than in controls, reflecting the alveolar damage typical of this rare interstitial lung disease.

MicroRNAs in pulmonary sarcoidosis: A systematic review

Sarcoidosis is a multisystemic granulomatous disorder of unknown etiology. Diagnosis of sarcoidosis is made by correlating clinical and radiological features along with the histopathological demonstration of non-necrotizing granulomas in tissue samples. Diagnosis is often challenging as the clinical profile may mimic other granulomatous disorders, including infections, inflammatory diseases, and lymphoid malignancies. Differentiation from tuberculosis is especially crucial in endemic regions where exclusion of mediastinal tuberculosis is necessary before any immunosuppressant treatment can be initiated for symptomatic sarcoidosis. Identification of biomarkers, which can aid in diagnosis as well as prognosis, can be helpful in clinical decision making. MicroRNAs are small non-coding regulatory RNAs that serve as post-transcriptional regulators of gene expression and have been studied as emerging biomarkers in many other respiratory diseases, including lung cancer, asthma, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. In the context of sarcoidosis, miRNA expression has been studied in the lungs, lymph nodes, bronchoalveolar lavage fluid, and peripheral blood mononuclear cells. A comprehensive search of the PubMed database was performed by two authors independently, and relevant studies were retrieved for review. This systematic review summarizes the current information on miRNAs in sarcoidosis, the biological mechanisms involved in CD4⁺ T-helper 1 and macrophage polarization, and the use of exhaled breath condensate as an alternative, noninvasive and potential source of miRNAs.

Lung CD4+ Vα2.3+ T-cells in sarcoidosis cohorts with Löfgren's syndrome

Background

Sarcoidosis is diagnosed by a combination of typical clinical and radiological findings together with biopsy proof of non-caseating epithelioid cell granulomas in affected tissues and/or the cell distribution in bronchoalveolar lavage fluid (BALF). We aimed at investigating the usefulness of measuring the proportion of T-cell receptor (TCR) CD4+ Vα2.3+ T-cells in BALF as an additive marker to CD4/CD8-ratio to confirm the diagnosis.

Methods

From a register consisting of 749 sarcoidosis patients [Löfgren’s syndrome (LS) n = 274, non-LS n = 475] with information on Vα2.3+ T-cells, an expansion of CD4+ Vα2.3+ T-cells (CD4+ Vα2.3+ T cells > 10.5% in BALF) was seen in 268 (36%). Controls were healthy volunteers (n = 69) and patients with other pulmonary conditions (n = 39), investigated because of suspicion of sarcoidosis.

Results

A proportion of CD4+ Vα2.3+ T-cells in BALF > 10.5% was highly specific for sarcoidosis, with a specificity of 97% and with a sensitivity of 36% (p < 0.0001). Receiver operating characteristic (ROC) curves show that testing for CD4+ Vα2.3+ T-cells in BALF was a more useable test in individuals with LS [area under the curve (AUC) 0.82, p < 0.0001] compared to the whole patient group (AUC 0.64, p < 0.0001).

Conclusion

In this study, we show that an increased proportion of CD4+ Vα2.3+ T-cells in BALF is highly specific for sarcoidosis. This suggests that this T-cell subset could be used as an additional tool to the CD4/CD8-ratio to support the sarcoidosis diagnosis, particularly in patients with LS but also in patients with non-LS.

BAL biomarkers' panel for differential diagnosis of interstitial lung diseases

Bronchoalveolar lavage (BAL) is a useful procedure for differential diagnosis of interstitial lung diseases (ILDs) and for identification of granulomatous lung diseases. We investigated a panel of biomarkers from BAL fluid of ILD patients to evaluate their utility in differentiating ILDs. Bronchoscopy with BAL was performed in 100 consecutive patients with suspected ILD (41 sarcoidosis, 11 cHP and 24 other ILDs); the 24 patients negative for ILD diagnosis were included as control group. BAL phenotypes and cell profiles (CD4⁺/CD8⁺ ratio, NK and CD103⁺ cell counts, chitotriosidase and KL-6 levels in BAL) were determined by flow cytometry. A decision-tree statistical algorithm was applied. Sarcoidosis was discriminated by a higher BAL CD4⁺/CD8⁺ ratio (p = 5.8E-05), a lower BAL CD103⁺CD4⁺ count (p = 5.0E-02) and lower BAL NK percentages (p = 8.8E-03) than the other groups. BAL KL-6 concentrations were higher in sarcoidosis than in other ILDs (p = 1.5E-02) and were directly correlated with CD4⁺/CD8⁺ ratio. We used decision-tree statistical analysis to combine our biomarkers into two diagnostic algorithms for differential diagnosis of ILDs. A panel of BAL biomarkers for diagnosis of ILDs is proposed; CD4⁺/CD8⁺ ratio, KL-6 concentrations, and NK and CD103⁺CD4⁺ cell percentages in BAL could improve the identification and differential diagnosis of sarcoidosis.