NK and NKT-like cells in granulomatous and fibrotic lung diseases

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.

Imbalance of Lymphocyte Subsets and CD45RA-Expressing Cells in Intrathoracic Lymph Nodes, Alveolar Compartment and Bloodstream of Pulmonary Sarcoidosis Patients

Sarcoidosis is a systemic granulomatous disease mainly affecting the lungs and hilomediastinal lymph nodes. It is characterized by non-caseating epithelioid cell granulomas in lymph nodes and lungs. Our study aimed to evaluate and compare T, B and NK cell subsets in the alveolar compartment, lymph nodes and the bloodstream simultaneously in the same patients to elucidate the immune responses associated with the development and progression of sarcoidosis. A secondary aim was to evaluate the distribution of CD45RA-expressing cells in the different anatomical compartments. Patients suspected to have sarcoidosis and who underwent bronchoscopy with bronchoalveolar lavage (BAL), lung-draining lymph node (LLN) biopsy by EBUS-TBNA and peripheral blood (PB) sampling were included in the study. They were monitored at the Regional Referral Centre of Siena University Hospital and the Respiratory Diseases Unit of Perugia Hospital. Multicolour flow cytometry analysis through FASCLyric was performed to assess T, B and NK cell subsets. Thirty-two patients (median age (IQR) 57 (52-58) years) were consecutively and prospectively enrolled. Machine learning analysis created a model which selected CD56dim16bright, CD8, Tfc, Th17, Th12, Tfh17, Tfh2, Tc_emRA, Th_emRA, T naïve, Tc naïve, Breg, CD1d⁺CD5⁺, Th-reg, Tfh, Th1 and CD4 cells with an accuracy of 0.9500 (kappa 0.8750). Comparative analysis found 18 cell populations that differed significantly between the three anatomical compartments. The bloodstream was enriched in Th_emRA (p = 0.0416), Tfh2 (p = 0.0189), Tfh17 (p = 0.0257), Th2 (p = 0.0212), Th17 (p = 0.0177), Th-naïve (p = 0.0368), CD56dimCD16bright (p < 0.0001), CD8 (p = 0.0319), Tc_emRA (p < 0.0001) and Tfc cells (p = 0.0004) compared with the alveolar compartment, while Th-reg were lower in PB than BAL (p = 0.0329). The alveolar compartment was enriched in Breg (p = 0.0249) and CD1d⁺CD5⁺ (p = 0.0013) with respect to LLN samples and PB. Conversely, Tfh (p = 0.0470), Th1 (p = 0.0322), CD4 (p = 0.0486) and Tc-naïve (p = 0.0009) were more abundant in LLN than in BAL and PB. It has been speculated that changes in the relative contents of PB cells could be related to changes in production and to the selective redistribution of PB cells to granulomatous foci. This study further supports the fact that sarcoidosis is multisystemic in nature. However, the low level of immune cells in peripheral blood of patients with sarcoidosis is concerning. A re-expression of CD45RA on CD4⁺ and CD8⁺ cells could result in a reduction in peripheral immune activity. Thus, changes in the spectrum of the bloodstream may reflect both pathogenic and compensatory processes.

The Effects of Interstitial Lung Diseases on Alveolar Extracellular Vesicles Profile: A Multicenter Study

Diagnosis of interstitial lung diseases (ILD) is difficult to perform. Extracellular vesicles (EVs) facilitate cell-to-cell communication, and they are released by a variety of cells. Our goal aimed to investigate EV markers in bronchoalveolar lavage (BAL) from idiopathic pulmonary fibrosis (IPF), sarcoidosis and hypersensitivity pneumonitis (HP) cohorts. ILD patients followed at Siena, Barcelona and Foggia University Hospitals were enrolled. BAL supernatants were used to isolate the EVs. They were characterized by flow cytometry assay through MACSPlex Exsome KIT. The majority of alveolar EV markers were related to the fibrotic damage. CD56, CD105, CD142, CD31 and CD49e were exclusively expressed by alveolar samples from IPF patients, while HP showed only CD86 and CD24. Some EV markers were common between HP and sarcoidosis (CD11c, CD1c, CD209, CD4, CD40, CD44, CD8). Principal component analysis distinguished the three groups based on EV markers with total variance of 60.08%. This study has demonstrated the validity of the flow cytometric method to phenotype and characterize EV surface markers in BAL samples. The two granulomatous diseases, sarcoidosis and HP, cohorts shared alveolar EV markers not revealed in IPF patients. Our findings demonstrated the viability of the alveolar compartment allowing identification of lung-specific markers for IPF and HP.

Causal association of peripheral immune cell counts and atrial fibrillation: A Mendelian randomization study

Background

Atrial fibrillation (AF) is the most common and persistent form of arrhythmia. Recently, increasing evidence has shown a link between immune responses and atrial fibrillation. However, whether the immune response is a cause or consequence of AF remains unknown. We aimed to determine whether genetically predicted peripheral immunity might have a causal effect on AF.

Methods

First, we performed Mendelian randomization (MR) analyses using genetic variants strongly associated with neutrophil, eosinophil, basophil, lymphocyte, and monocyte cell counts as instrumental variables (IVs). Lymphocyte counts were then subjected to further subgroup analysis. The effect of immune cell counts on AF risk was measured using summary statistics from genome-wide association studies (GWAS).

Results

Two-sample MR analysis revealed that a higher neutrophil count, basophil count and lymphocyte count had a causal effect on AF [Odds ratio (OR), 1.06, 95% confidence interval (CI), 1.01-1.10, P = 0.0070; OR, 1.10; 95% CI, 1.04-1.17; P = 0.0015; OR, 0.96; 95% CI, 0.93-0.99; P = 0.0359]. In addition, in our further analysis, genetically predicted increases in CD4 + T-cell counts were also associated with an increased risk of AF (OR, 1.04; 95% CI, 1.0-.09; P = 0.0493).

Conclusion

Our MR analysis provided evidence of a genetically predicted causal relationship between higher peripheral immune cell counts and AF. Subgroup analysis revealed the key role of peripheral lymphocytes in AF, especially the causal relationship between CD4 + T cell count and AF. These findings are beneficial for future exploration of the mechanism of AF.

Characterization of natural killer and T cells in bronchoalveolar lavage and peripheral blood of sarcoidosis patients

The characterization of frequency and phenotypes of natural killer (NK) cells and T cells in BAL and peripheral blood of patients with sarcoidosis was evaluated, to discriminate the differential status of these cells in these two compartments. The analysis revealed that CD56^brightCD16^neg resulted higher in BAL than PB of sarcoidosis and healthy subjects, while CD56^dimCD16⁺ showed a different proportion between BAL and PB of both Sarcoidosis patients and HC. Moreover, in comparison with autologous PB, BAL was characterized by a higher expression of activated NK cell markers NKp44, CD69 and CD25. Significantly increased levels of PD-1⁺ NK cells in the BAL of patients were detected. Regarding the maturation of CD4 and CD8, an increase of Effector Memory T cells (T_EM) was reported in BAL compared to PB. A better characterization of NK and T cells may lead to an improvement of the pathogenetic mechanisms in sarcoidosis.

Analysis of lymphocyte profile in lymph nodes, bronchoalveolar lavage fluid and peripheral blood in patients with stage II sarcoidosis

OBJECTIVE

To evaluate the lymphocyte profile (LP) in lymph node puncture fluid (LNPF) of mediastinal and hilar lymph nodes, bronchoalveolar lavage fluid (BALF), and peripheral blood (PB) involved in stage 2 sarcoidosis.

METHODS

After selection, 31 patients diagnosed with stage II sarcoidosis were finally included. Patients were further divided into symptomatic (n = 17) and asymptomatic (n = 14) groups according to the presence or absence of respiratory symptoms. The LP in lymph node puncture fluid (LNPF), bronchoalveolar lavage fluid (BALF), and peripheral blood (PB) were evaluated and compared using flow cytometry. The relationship between respiratory symptoms and LP was preliminarily analyzed.

RESULTS

The proportions of T cells and CD4 T cells, and CD4/CD8 ratio in BALF were significantly higher than that of LNPF with PB (all P < 0.05). The proportions of lymphocyte cells, CD8 T cells, NK cells, and CD4/CD8 ratio in LNPF and PB were significantly different (all P < 0.05). There were significant differences in CD4 T cells [72.40 (68.90,75.55) vs.46.30 (38.55,52.50), P = 0.004], CD8 T cells (9.9 ± 3.9 vs. 16.8 ± 6.8, P = 0.002), and CD4/CD8 ratio (7.9 ± 2.8 vs. 3.9 ± 1.5, P < 0.001) in BALF between the symptomatic group and asymptomatic group (all P < 0.05). The T cells (rs = 0.447, P = 0.011), CD4 (rs = 0.572, P = 0.002), and CD4/CD8 ratio (rs = 0.701, P < 0.001) in BALF were positively correlated with respiratory symptoms.

CONCLUSION

The LP in LNPF, BALF and PB were significantly different and the main index correlated with respiratory symptoms was CD4/CD8 ratio in BALF. The difference of LP in BALF and LNPF may help to deeply understand the pathophysiological process and may reflect the different degree of lung and lymph node lesion.

A LIGHT-HVEM/LTβR axis contributes to the fibrosis of intrauterine adhesion

Intrauterine adhesion (IUA) is a fibrotic disease, with complex and multifactorial process, causing menstrual disorders, pregnancy loss or infertility. LIGHT (also named TNFSF14), mainly expressed by immune cells, has been reported to be associated with tissue fibrosis. However, the features of immunocyte subsets, the expression and roles of LIGHT and its receptor HVEM (herpes virus entry mediator) and LTβR (lymphotoxin beta receptor) in IUA remain largely unknown. Compared with the control group, we observed increased ratios of CD45⁺ cells, neutrophils, T cells, macrophages and decreased natural killer cells proportion, and high LIGHT expression on CD4⁺ T cells and macrophages in IUA endometrium. Further analysis showed there was a positive correlation between upregulated profibrotic factors (e.g., ɑ-smooth muscle actin, transforming growth factor β1) and HVEM in IUA endometrial tissue. More importantly, recombinant human LIGHT protein directly up-regulated the expression of HVEM, LTβR, profibrotic and proinflammatory factors expression in human endometrial stromal cells. These findings reveal abnormal changes of immune cell subsets proportion and the overexpression of LIGHT-HVEM/LTβR axis in IUA endometrium, should contribute to inflammation and fibrosis formation of IUA.

Characterization of NKG2-A/-C, Kir and CD57 on NK Cells Stimulated with pp65 and IE-1 Antigens in Patients Awaiting Lung Transplant

Introduction: Cytomegalovirus (CMV) is the leading opportunistic infection in lung transplant (LTx) recipients. CMV is associated with graft failure and decreased survival. Recently, new antiviral therapies have been proposed. The present study aimed to investigate NK and T cell subsets of patients awaiting LTx. We analyzed the cellular populations between reactive and non-reactive QuantiFERON (QF) CMV patients for the prediction of immunological response to infection. Methods: Seventeen pre-LTx patients and 15 healthy controls (HC) have been enrolled. QF and IFN-γ ELISA assay detections were applied. NK cell subsets and T cell and proliferation assay were detected before and after stimulation with pp-65 and IE-1 CMV antigens after stratification as QF+ and QF−. Furthermore, we quantified the serum concentrations of NK− and T-related cytokines by bead-based multiplex analysis. Results: CD56^brCD16^lowNKG2A⁺KIR⁺ resulted in the best discriminatory cellular subsets between pre-LTx and HC. Discrepancies emerged between serology and QF assay. Better proliferative capability emerged from patients who were QF+, in particular in CD8 and CD25-activated cells. CD56^brCD16^low, adaptive/memory-like NK and CD8Teff were highly increased only in QF+ patients. Conclusions: QF more than serology is useful in the detection of patients able to respond to viral infection. This study provides new insights in terms of immunological responses to CMV in pre-LTX patients, particularly in NK and T cells biology.

Immune-Checkpoint Expression on CD4, CD8 and NK Cells in Blood, Bronchoalveolar Lavage and Lymph Nodes of Sarcoidosis

Background

Sarcoidosis features non-necrotizing granulomas consisting mainly of activated CD4-lymphocytes. T-cell activation is regulated by immune checkpoint (IC) molecules. The present study aimed to compare IC expression on CD4, CD8 and NK cells from peripheral, alveolar and lung‐draining lymph node (LLN) samples of sarcoidosis patients.

Methods

Flow-cytometry analysis was performed to detect IC molecules and a regression decision tree model was constructed to investigate potential binary classifiers for sarcoidosis diagnosis as well as for the IC distribution.

Results

Fourteen patients (7 females) were consecutively recruited in the study; all enrolled patients showed hilo-mediastinal lymph node enlargement and lung parenchyma involvement with chest X-rays and high resolution computed tomography. CD4+PD1+ and CD8+PD1+ were higher in bronchoalveolar lavage (BAL) than in LLN (p = 0.0159 and p = 0.0439, respectively). CD4+ T-cell immunoglobulin and ITIM domain (TIGIT)+ were higher in BAL than in peripheral blood mononuclear cells (PBMCs) (p = 0.0239), while CD8+TIGIT+ were higher in PBMC than in BAL (p = 0.0386). CD56+TIGIT+ were higher in LLN than in PBMC (p = 0.0126). The decision-tree model showed the best clustering cells of PBMC, BAL and LLN: CD56, CD4/CD8 and CD4+TIGIT+ cells. Considering patients and controls, the best subset was CD4+CTLA-4+.

Conclusion

High expression of PD1 and TIGIT on T cells in BAL, as well as CTLA-4 and TIGIT on T cells in LLN, suggest that inhibition of these molecules could be a therapeutic strategy for avoiding the development of chronic inflammation and tissue damage in sarcoidosis patients.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40291-022-00596-0.

Peripheral blood natural killer cells in sarcoidosis are associated with early cardiac involvement

AIM

To evaluate the distribution of circulating immune cell subsets in peripheral blood of patients with sarcoidosis and investigate if there is an association with an underlying cardiac involvement.

METHODS AND RESULTS

Eighty-five newly diagnosed treatment-naïve patients with sarcoidosis (50 women) were included in the study. All patients underwent a thorough cardiac investigation, including cardiac magnetic resonance imaging (CMR). Of all patients, 19 (23.53%) had myocardial involvement, and the NK subpopulation in these patients in peripheral blood was significantly decreased compared to patients without (n = 63, p = 0.001 and p = 0.003 respectively). The absolute number of NKT cells (CD3+CD16/56⁺ ) in patients with cardiac involvement was highly correlated with T2 map increased values in MRI (r = -686, p = 0.041) showing that low NKT cell count correlates with the inflammatory process of the heart. No difference in CD19, CD3, CD4, CD8 and CD3^- NK cell counts was found between groups. Lung severity was not found to correlate with the number of NK cells.

CONCLUSION

We found that low NK cell count in peripheral blood of patients with sarcoidosis is associated with cardiac involvement, and the number of NK-T cells correlates with CMR findings indicative of myocardial inflammation. This finding might have a potential clinical application in detecting clinically silent cardiac involvement in sarcoidosis and may also suggest potential targets for therapeutic interventions.

The Combined Model of CX3CR1-Related Immune Infiltration Genes to Evaluate the Prognosis of Idiopathic Pulmonary Fibrosis

Background

High expression of chemokine (C-X3-C motif) receptor 1 (CX3CR1) was shown to contribute to the progression of many fibrotic diseases. However, there is still no study for the role of CX3CR1 in idiopathic pulmonary fibrosis (IPF). Therefore, we aimed to identify CX3CR1-related immune infiltration genes (IIGs) in IPF and establish a combined risk model to evaluate the prognosis of IPF.

Methods

A discovery cohort of IPF patients (GSE70867) was downloaded from the Gene Expression Omnibus dataset. We identified the composition of 22 kinds of immune cells infiltration by CIBERSORT. The Cox regression model with the LASSO method was used for identifying prognostic genes and developing CX3CR1-related IIGs. Kaplan–Meier was applied to plot the survival curve of prognosis model. Peripheral blood mononuclear cell (PBMC) and bronchoalveolar lavage fluid (BALF) were collected to be tested by quantitative reverse transcriptase-PCR (qRT-PCR) from 15 clinical samples, including 8 healthy controls (HC), 4 patients with usual interstitial pneumonia (UIP) and 3 patients with pulmonary fibrosis (FIB).

Results

We found that high expression of CX3CR1 in BALF contributed to the poor prognosis in IPF patients. ALR4C, RAB37, GPR56, MARCKS, PXN and RASSF2 were identified as CX3CR1-related IIGs, which were highly expressed in PBMC of UIP/FIB patients than that of HC. Moreover, the expression of PXN was higher in FIB patients’ PBMC than that of UIP ones. In the cohort of IPF patients, high infiltration of activated NK cells in BALF caused poor survival compared to low infiltration group. The infiltration of activated NK was regulated by CX3CR1-related IIGs. The combined risk model predicted that high expression of CX3CR1-related IIGs and high infiltrated activated NK cells caused poor prognosis in IPF patients.

Conclusion

We identified a group of CX3CR1-related IIGs in IPF patients. This combined risk model provided new insights in the prognosis and therapy of IPF.

BALF and BLOOD NK- cells in different stages of pulmonary sarcoidosis

Background and objective:

Data on natural killer (NK)- and natural killer T (NKT)- like cells in the immunopathogenesis of sarcoidosis remain limited. The aim was to assess NK- and NKT-like cells across different stages in bronchoalveolar lavage (BALF) versus peripheral blood (PB) in comparison to controls.

Methods:

Forty four patients (32 women and 12 men, mean age 46.6±14.4 years) with biopsy-proven sarcoidosis and 10 healthy individuals (6 women, 4 men mean age 52.6±19.1 years) were submitted to BALF. Total cells and cell differentials were counted, while CD45+, CD3+, CD4+, CD8+, CD19+, CD3-CD16/56 (NK cells) and CD3+CD16/56+ (NKT-like cells) were determined by dual flow cytometry in BALF and PB.

Results:

A significantly lower percentage of both NK and NKT-like cells was observed in BALF of controls and sarcoid patients (SP) compared to PB. Both BALF NK and NKT-cell counts were significantly higher in SP than in controls (NK: p=0.046, NKT-like: p=0.012) In addition BALF NK cell percentage differed among sarcoidosis stages (p=0.005). In PB NK-cell count was lower in sarcoidosis patients but the difference did not reach statistical significance. Also, in sarcoid patients’ BALF NK-cell percentage negatively correlated with lymphocyte percentage (r=-0.962, p<0.001).

Conclusions:

The increased count of BALF NK and NKT-like cells in sarcoidosis compared to controls along with the increase of NK cells with stage progression are in line with a growing number of investigations suggesting the involvement of NK- and NKT-like cells in the pathogenesis of sarcoidosis.

Fatty acid metabolism-related genes in bronchoalveolar lavage fluid unveil prognostic and immune infiltration in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive condition with an unfavorable prognosis. A recent study has demonstrated that IPF patients exhibit characteristic alterations in the fatty acid metabolism in their lungs, suggesting an association with IPF pathogenesis. Therefore, in this study, we have explored whether the gene signature associated with fatty acid metabolism could be used as a reliable biological marker for predicting the survival of IPF patients.

METHODS

Data on the fatty acid metabolism-related genes (FAMRGs) were extracted from databases like Kyoto Encyclopedia of Genes and Genomes (KEGG), Hallmark, and Reactome pathway. The GSE70866 dataset with information on IPF patients was retrieved from the Gene Expression Omnibus (GEO). Next, the consensus clustering method was used to identify novel molecular subgroups. Gene Set Enrichment Analysis (GSEA) was performed to understand the mechanisms involved. The Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) algorithm was used to evaluate the level of immune cell infiltration in the identified subgroups based on gene expression signatures of immune cells. Finally, the Least Absolute Shrinkage and Selection Operator (LASSO) regression and multivariate Cox regression analysis were performed to develop a prognostic risk model.

RESULTS

The gene expression signature associated with fatty acid metabolism was used to create two subgroups with significantly different prognoses. GSEA reveals that immune-related pathways were significantly altered between the two subgroups, and the two subgroups had different metabolic characteristics. High infiltration of immune cells, mainly activated NK cells, monocytes, and activated mast cells, was observed in the subgroup with a poor prognosis. A risk model based on FAMRGs had an excellent ability to predict the prognosis of IPF. The nomogram constructed using the clinical features and the risk model could accurately predict the prognosis of IPF patients.

CONCLUSION

The fatty acid metabolism-related gene expression signature could be used as a potential biological marker for predicting clinical outcomes and the level of infiltration of immune cells. This could eventually enhance the accuracy of the treatment of IPF patients.

Potential therapeutic targets to prevent organ damage in chronic pulmonary sarcoidosis

INTRODUCTION

Sarcoidosis is a granulomatous inflammatory disease with high chances of reduced quality of life, irreversible organ damage, and reduced life expectancy when vital organs are involved. Any organ system can be affected, and the lungs are most often affected. There is no preventive strategy as the exact etiology is unknown, and complex immunogenetic and environmental factors determine disease susceptibility and phenotype. Present-day treatment options originated from clinical practice and are effective in many patients. However, a substantial percentage of patients suffer from unacceptable side effects or still develop refractory, threatening pulmonary or extrapulmonary disease.

AREAS COVERED

As non-caseating granulomas, the pathological hallmark of disease, are assigned to divergent activation and regulation of the immune system, targets in relation to the possible triggers of granuloma formation and their sequelae were searched and reviewed.

EXPERT OPINION

:The immunopathogenesis underlying sarcoidosis has been a dynamic field of study. Several recent new insights give way to promising new therapeutic targets, such as certain antigenic triggers (e.g. from Aspergillus nidulans), mTOR, JAK-STAT and PPARγ pathways, the NRP2 receptor and MMP-12, which await further exploration. Clinical and trigger related phenotyping, and molecular endotyping in sarcoidosis will likely hold the key for precision medicine in the future.

The Role of Diverse Immune Cells in Sarcoidosis

Sarcoidosis is a systemic inflammatory disorder of unknown etiology characterized by tissue infiltration with macrophages and lymphocytes and associated non-caseating granuloma formation. The disease primarily affects the lungs. Patients suffering from sarcoidosis show a wide range of clinical symptoms, natural history and disease outcomes. Originally described as a Th1-driven disease, sarcoidosis involves a complex interplay among diverse immune cells. This review highlights recent advances in the pathogenesis of sarcoidosis, with emphasis on the role of different immune cells. Accumulative evidence suggests Th17 cells, IFN-γ-producing Th17 cells or Th17.1 cells, and regulatory T (Treg) cells play a critical role. However, their specific actions, whether protective or pathogenic, remain to be clarified. Macrophages are also involved in granuloma formation, and M2 polarization may be predictive of fibrosis. Previously neglected cells including B cells, dendritic cells (DCs), natural killer (NK) cells and natural killer T (NKT) cells were studied more recently for their contribution to sarcoid granuloma formation. Despite these advances, the pathogenesis remains incompletely understood, indicating an urgent need for further research to reveal the distinct immunological events in this process, with hope to open up new therapeutic avenues and if possible, to develop preventive measures.

NK and T Cell Immunological Signatures in Hospitalized Patients with COVID-19

Severe acute respiratory syndrome caused by coronavirus 2 emerged in Wuhan (China) in December 2019 and has severely challenged the human population. NK and T cells are involved in the progression of COVID-19 infection through the ability of NK cells to modulate T-cell responses, and by the stimulation of cytokine release. No detailed investigation of the NK cell landscape in clinical SARS-CoV-2 infection has yet been reported. A total of 35 COVID-19 hospitalised patients were stratified for clinical severity and 17 healthy subjects were enrolled. NK cell subsets and T cell subsets were analysed with flow cytometry. Serum cytokines were detected with a bead-based multiplex assay. Fewer CD56dimCD16brightNKG2A+NK cells and a parallel increase in the CD56+CD69+NK, CD56+PD-1+NK, CD56+NKp44+NK subset were reported in COVID-19 than HC. A significantly higher adaptive/memory-like NK cell frequency in patients with severe disease than in those with mild and moderate phenotypes were reported. Moreover, adaptive/memory-like NK cell frequencies were significantly higher in patients who died than in survivors. Severe COVID-19 patients showed higher serum concentrations of IL-6 than mild and control groups. Direct correlation emerged for IL-6 and adaptive/memory-like NK. All these findings provide new insights into the immune response of patients with COVID-19. In particular, they demonstrate activation of NK through overexpression of CD69 and CD25 and show that PD-1 inhibitory signalling maintains an exhausted phenotype in NK cells. These results suggest that adaptive/memory-like NK cells could be the basis of promising targeted therapy for future viral infections.

Prognostic role of NK cell percentages in bronchoalveolar lavage from patients with different fibrotic interstitial lung diseases

BAL cellularity and lymphocyte immunophenotyping offer insights into lung inflammatory status. Natural killer (NK) cells are efficient effector cells, producing pro-inflammatory cytokines. A better understanding of the biology of NK cells in BAL in the lungs is necessary to improve the pathogenesis of fibrotic ILD and develop prospective targeted treatments. Our aim was to analyse NK and NKT-like cell percentages in BAL from 159 patients with different ILD: f-HP, f-NSIP, IPF and CTD-ILD, to evaluate their potential diagnostic/prognostic role. BAL NK cell percentages showed significantly higher values in IPF than in f-HP and f-NSIP, while BAL NKT-like cells showed significantly lower values in the f-NSIP than the f-HP and IPF. A cut-off of 4%NK cells in BAL of IPF showed a significant difference in survival rate. It suggests a possible new marker of survival and raises the possibility of new targeted approach in treatment and management of IPF.

Effects of infliximab on lung and circulating natural killer cells, CD56+ T cells and B cells in sarcoidosis

Background

Tumour necrosis factor α (TNF-α) is pivotal in sarcoid granuloma formation, and inhibitors of TNF-α offer an attractive third-line treatment option in sarcoidosis. The sarcoid inflammation is characterised by an exaggerated T helper 1 response, and evidence indicates a contribution of dysregulated and/or deficient NK (natural killer) cells, CD56+ T cells and B cells.

Objectives

Insight into how TNF-α inhibitors influence these cells may provide more information on inflammatory mechanisms in sarcoidosis and improve understanding of such treatment. We therefore evaluated treatment effects of the TNF-α inhibitor infliximab on lung and peripheral blood (PB) NK, CD56+ T cells and B cells.

Methods

Fifteen patients were assessed with PB samples, spirometry and CT scan, and 11 of them also underwent bronchoalveolar lavage (BAL) close to start of infliximab treatment. These investigations were repeated after 6 months of treatment.

Results

Twelve out of 15 patients disclosed a clinical improvement at follow-up. Median percentage of BAL fluid (BALF) CD56+ T cells increased while a decrease was seen in PB (p<0.05 and 0.005, respectively). No significant changes were observed for NK cells. There was a trend towards increased median percentage of PB B cells (p=0.07), and a negative correlation was observed between PB and BALF B cells after treatment (p<0.05).

Conclusion

In conclusion, 6 months of infliximab treatment in patients with sarcoidosis, of whom the majority benefited from the treatment, influenced immune cells in the lung and circulation differently, highlighting the importance of investigating several compartments concomitantly when evaluating treatment effects on the inflammatory activity.

Adaptive immune system in pulmonary sarcoidosis-Comparison of peripheral and alveolar biomarkers

Sarcoidosis is a multi‐systemic granulomatous disease of unknown origin. Recent research has focused upon the role of autoimmunity in its development and progression. This study aimed to determine and define the disturbance and distribution of T and B cell subsets in the alveolar and peripheral compartments. Thirteen patients were selected for the study [median age, interquartile range (IQR) = 57 years (48–59); 23% were male]. Twelve healthy controls [median age, IQR = 53 years (52–65); 16% male] were also enrolled into the study. Cellular and cytokine patterns were measured using the cytofluorimetric approach. Peripheral CD8 percentages were higher in sarcoidosis patients (SP) than healthy controls (HC) (p = 0.0293), while CD4 percentages were lower (p = 0.0305). SP showed low bronchoalveolar lavage (BAL) percentages of CD19 (p = 0.0004) and CD8 (p = 0.0035), while CD19⁺CD5⁺CD27⁻ percentages were higher (p = 0.0213); the same was found for CD4 (p = 0.0396), follicular regulatory T cells (T_reg) (p = 0.0078) and T_reg (p < 0.0001) cells. Low T helper type 17 (Th17) percentages were observed in BAL (p = 0.0063) of SP. Peripheral CD4⁺ C‐X‐C chemokine receptor (CXCR)5⁺CD45RA⁻) percentages and follicular T helper cells (Tfh)‐like Th1 (Tfh1) percentages (p = 0.0493 and p = 0.0305, respectively) were higher in the SP than HC. Tfh1 percentages and Tfh‐like Th2 percentages were lower in BAL than in peripheral blood (p = 0.0370 and p = 0.0078, respectively), while CD4⁺ C‐X‐C motif CXCR5⁺CD45RA⁻ percentages were higher (p = 0.0011). This is the first study, to our knowledge, to demonstrate a link between an imbalance in circulating and alveolar Tfh cells, especially CCR4‐, CXCR3‐ and CXCR5‐expressing Tfh subsets in the development of sarcoidosis. These findings raise questions about the pathogenesis of sarcoidosis and may provide new directions for future clinical studies and treatment strategies.

Integrated approach to bronchoalveolar lavage cytology to distinguish interstitial lung diseases

BACKGROUND

Broncho-alveolar lavage (BAL) is a safe diagnostic procedure, useful for differentiating fibrotic lung disorders and for excluding malignancy and infection. A recent multicenter study demonstrated a new, relatively sensitive, and specific index called Bronchoalveolar Cytology Threshold (BCT), useful for distinguishing healthy individuals from patients with lung diseases.

OBJECTIVES

In our study, BCT was applied for the first time to the analysis of interstitial lung diseases (ILDs), investigating its potential for differential diagnosis. Combinations of BAL cells that improve diagnostic accuracy for ILDs were studied and are proposed.

METHODS

A retrospective analysis of BAL samples was performed. We considered more than 1000 BAL samples from patients investigated for ILD, performed at Siena University Hospital. The samples enrolled for the study included 468 patients: 413 with and 55 without ILD. BAL was performed for diagnostic purposes in line with international guidelines. BCT were calculated according to available literature.

RESULTS

Among ILDs, patients with fibrotic hypersensitivity pneumonitis, idiopathic pulmonary fibrosis (IPF) and sarcoidosis showed significantly lower BCTs than unclassified ILD. Asbestosis patients showed significantly lower BCTs than nonspecific interstitial pneumonia (NSIP), cryptogenic organizing pneumonia (COP), connective tissue disease related ILD (CTD-ILD), sarcoidosis and unclassified ILD patients. COP patients showed significantly higher BCT than IPF, f-HP and sarcoidosis. Moreover, COP patients were best distinguished by BCT.

CONCLUSION

The analysis of BAL features is currently included in the diagnostic algorithm of ILDs. BAL cell patterns and BCT index can provide useful information for distinguishing ILDs, reducing the need for invasive procedures. Integrated approaches to BAL analysis can improve the interpretation of results without further cost or loss of time.

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.

Gene fusion of IL7 involved in the regulation of idiopathic pulmonary fibrosis

Background:

Idiopathic pulmonary fibrosis (IPF) is a rare form of immune-mediated interstitial lung disease characterized by progressive pulmonary fibrosis and scarring. The pathogenesis of IPF is still unclear. Gene fusion events exist universally during transcription and show alternated patterns in a variety of lung diseases. Therefore, the comprehension of the function of gene fusion in IPF might shed light on IPF pathogenesis research and facilitate treatment development.

Methods:

In this study, we included 91 transcriptome datasets from the National Center for Biotechnology Information (NCBI), including 52 IPF patients and 39 healthy controls. We detected fusion events in these datasets and probed gene fusion-associated differential gene expression and functional pathways. To obtain robust results, we corrected the batch bias across different projects.

Results:

We identified 1550 gene fusion events in all transcriptomes and studied the possible impacts of IL7 = AC083837.1 gene fusion. The two genes locate adjacently in chromosome 8 and share the same promoters. Their fusion is associated with differential expression of 282 genes enriched in six Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and 35 functional gene sets. Gene ontology (GO) enrichment analysis shows that IL7 = AC083837.1 gene fusion is associated with the enrichment of 187 gene sets. The co-expression network of interleukin-7 (IL7) indicates that decreased IL7 expression is associated with many pathways that regulate IPF progress.

Conclusion:

Based on the results, we conclude that IL7 = AC083837.1 gene fusion might exacerbate fibrosis in IPF via enhancing activities of natural killer cell-mediated cytotoxicity, skin cell apoptosis, and vessel angiogenesis, the interaction of which contributes to the development of fibrosis and the deterioration of respiratory function of IPF patients. Our work unveils the possible roles of gene fusion in regulating IPF and demonstrates that gene fusion investigation is a valid approach in probing immunologic mechanisms and searching potential therapeutic targets for treating IPF.

The reviews of this paper are available via the supplemental material section.

An inflammatory triangle in Sarcoidosis: PPAR-γ, immune microenvironment, and inflammation

INTRODUCTION

Sarcoidosis is an inflammatory disorder characterized by granuloma formation in several organs. Sarcoidosis patients experience higher inflammatory responses resulting in pulmonary fibrosis. Although the precise mechanisms have not been well elucidated, the relationship between the immune system activation and inflammatory status is pivotal in the pathogenesis of sarcoidosis.

AREAS COVERED

Peroxisome proliferator-activated receptor (PPAR) includes the transcription factors involved in cell metabolism, proliferation, and immune response. In the alveolar macrophages of patients with sarcoidosis, the reduced activity and a decreased level of PPAR-γ have been shown. In this study, we discuss how reducing the level of PPAR-γ could lead to increased inflammation and immune responses in patients with sarcoidosis.

EXPERT OPINION

Lack of PPAR-γ may contribute to the development of a suitable milieu for the formation of immune-associated pulmonary granuloma. Reduced levels of PPAR-γ in sarcoidosis could result from over-activation of the immune system and elevated inflammatory responses, as well. Due to the anti-inflammatory function of PPAR-γ, identifying the relation between PPAR-γ, sarcoidosis development, and inflammatory state could be essential to identify the appropriate therapeutic targets. The synthesis of PPAR-γ agonists or PPAR-γ ligands may be an effective step toward the treatment of sarcoidosis patients in the future.

Regulatory and Effector Cell Disequilibrium in Patients with Acute Cellular Rejection and Chronic Lung Allograft Dysfunction after Lung Transplantation: Comparison of Peripheral and Alveolar Distribution

Background: The immune mechanisms occurring during acute rejection (AR) and chronic lung allograft dysfunction are a challenge for research and the balance between effector and regulatory cells has not been defined completely. In this study, we aimed to elucidate the interaction of effector cells, mainly Th17, Th1 and Th2, and regulatory cells including (CD4⁺CD25⁺CD127^low/−) T reg cells and phenotypes of B regs, CD19⁺CD24^hiCD38^hi, CD19⁺CD24^hiCD27^hi and CD19⁺CD5⁺CD1d⁺. Methods: Bronchoalveolar lavage cells (BAL) and peripheral blood mononuclear cells (PBMCs) from stable lung transplanted (LTx )subjects (n = 4), AR patients (n = 6) and bronchiolitis obliterans syndrome (BOS) (n = 6) were collected at the same time. Cellular subsets were detected through flow cytometry. Results: A predominance of Th17 cells subtypes in the PBMCs and BAL and a depletion of Tregs, that resulted in decrease Treg/Th17 ratio, was observed in the AR group. CD19⁺CD24^hiCD38^hi Bregs resulted increased in BAL of AR patients. Th1 cells predominance and a reduction of Tregs cells was observed in BAL from AR patients. Moreover, multivariate analysis showed interdependences within studied variables revealing that effector cells and regulatory cells can effectively discriminate patients’ immunological status. Conclusions: In AR, BOS and stable lung transplant, regulatory and effector cells clearly demonstrated different pathways of activation. Understanding of the balance of T cells and T and B regulatory cells can offers insights into rejection.

Immunologic responses to antifibrotic treatment in IPF patients

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease limited to the lungs. Immunological dysregulation may significantly participate in the pathophysiology of IPF. The immunological responses to nintedanib therapy in IPF patients were investigated for the first time in this study.

MATERIALS AND METHODS

Fifty IPF patients (median age (IQR) 69 (65-75) years; 38 males), were selected retrospectively. Flowcytometry analysis were performed to phenotype immunological biomarkers in peripheral blood from IPF patients after 1 year of antifibrotic therapy and a group of healthy volunteers.

RESULTS

Before starting antifibrotic treatment, IPF patients showed increased CD1d+CD5+ (p = 0.0460), Treg (p = 0.0354), T effector (CD25^highCD127^high) (p = 0.0336), central cells (CD4⁺CD45RA^-) (p = 0.0354), effector cells (CD4⁺CD45RA⁺) (p = 0.0249) and follicular cell percentages (p = 0.0006), notably Tfh1 (p = 0.0412) and Tfh17 (p = 0.0051) cell percentages, in respect with healthy controls (HC). After nintedanib therapy, Breg (p = 0.0302), T effector (p = 0.0468), Th17.1 (p = 0.0146) and follicular cells (p = 0.0006), notably Tfh1 (p = 0.0006) and Tfh17 (p = 0.0182) cell percentages, were significantly decreased. In the logistic regression, Tfh panel showed a significant area under the receiver operating characteristics curve (AUROC) to distinguish IPF than HC (90.5%), as well as t0 and t1 (99.3%).

CONCLUSION

In conclusion, the immunological results obtained in this study demonstrate that nintedanib significantly helps to restore immunological responses in IPF patients. These findings will be useful in the search for biomarkers predictive of response to antifibrotic treatment.

Regulatory T cell monitoring in severe eosinophilic asthma patients treated with mepolizumab

Severe eosinophilic asthma (SEA) has been associated with T-helper type 2 (Th2) inflammatory response. A good understanding of T cell functions in asthma is important for therapy, especially in the choice of biological treatments for severe cases. Mepolizumab, an IL-5 antagonist, is indicated for the treatment of severe asthma. Regulatory T cells (Tregs) suppress inflammation by secreting cytokines that inhibit Th2 cell proliferation. We investigated peripheral Treg, CD4, CD8, CD19 and NK cell percentages and their relationship to clinical and functional parameters, including peripheral eosinophils, before and after anti-IL5 treatment. Subjects were 14 adult SEA patients (9 male, 54.1 ± 11.6 years), treated with mepolizumab, and 10 controls. T cells (CD4 and CD8), CD19, NK and Tregs were evaluated by flow cytometry. Comparison of lung function parameters before and after treatment with mepolizumab (T0 and T1) showed an increase in FEV1, FEV1/FVC ratio and a reduction in blood eosinophil percentages. CD8 and CD16/56⁺ CD3⁺ were significantly higher in SEA patients than controls (P = .04 and P = .03, respectively). A decrease in CD45+, CD8 + and CD16/56⁺ CD3⁺ cell percentages was observed between T0 and T1 (P = .02, P = .04, P = .03, respectively). A significant increase in Treg percentages (P = .0001) was recorded between T0 and T1. Mepolizumab therapy was found to modulate immune response, restoring immune balance in patients with SEA.

Serum Concentrations of KL-6 in Patients with IPF and Lung Cancer and Serial Measurements of KL-6 in IPF Patients Treated with Antifibrotic Therapy

Simple Summary

Evaluation of the prognostic significance of serial measurements of serum concentrations of Krebs von den Lungen-6 (KL-6) showed that an annual increment in KL-6 exceeding a threshold amount was an independent risk factor for progressive disease and poor prognosis. No literature data are available on long-term KL-6 measurements in the follow-up of IPF patients treated with Nintedanib. The aim of this study is to serially analyze KL-6 in idiopathic pulmonary fibrosis (IPF) patients after 24 months of Nintedanib and to investigate its biomarker potential in patients with IPF and lung cancer with respect to fibrotic hypersensitivity pneumonitis patients, pulmonary fibrosis associated with autoimmune diseases group and healthy controls.

Abstract

Background: Krebs von den Lungen-6 (KL-6) was suggested as ILD biomarker including idiopathic pulmonary fibrosis (IPF). Lung cancer is one of the most severe comorbidity of IPF patients. This study aims to serially analyze KL-6 in IPF patients after 24 months of Nintedanib and to first investigate the biomarker behavior in IPF associated with adenocarcinoma. Materials and methods: One hundred and forty-two ILD patients (median (IQR), 69 (63–75) years; 86 males) were retrospectively enrolled. Serial serum samples were collected from IPF patients before starting antifibrotic therapy and after 12 months. Serum KL-6 levels were measured by KL-6 reagent assay (Fujirebio Europe, UK). Results: Increased KL-6 concentrations were identified in IPF-LC patients than IPF, fibrotic hypersensitivity pneumonitis, and pulmonary fibrosis associated with autoimmune disease groups. A cut-off value was calculated to distinguish IPF and IPF-LC patients. IPF patients monitored for 24 months with Nintedanib showed persisted increased levels of KL-6 with a progressive decline of FVC percentages. Conclusion: This preliminary study offers a first demonstration that very high serum concentrations of KL-6 in IPF-LC patients are associated with poor prognosis. Moreover, serial evaluation of serum KL-6 in IPF patients over 24 months of Nintedanib treatment revealed that most patients experienced a stabilization of lung function parameters and of serum concentrations of KL-6.

Systematic Review and Metanalysis of Oncomarkers in IPF Patients and Serial Changes of Oncomarkers in a Prospective Italian Real-Life Case Series

Simple Summary

This paper is a review of the literature on the clinical role of oncomarkers in idiopathic pulmonary fibrosis (IPF) progression, and a description of the routine oncomarker trend in IPF patients over the longest follow-up yet reported. This is the first meta-analysis to review the results of studies evaluating the predictive prognostic value of circulating oncomarkers (CEA, Ca15.3, Ca19.9, Ca125, and KL-6) for IPF. The study focused on the discovery of multiple biomarker signatures, such as combinations of oncomarkers, that are widely and routinely available in biochemistry laboratories. The combination of clinical parameters and biological markers could help achieve more accurate results regarding prognosis and response to treatment in IPF. Our results could pave the way for a more “personalized” medical approach to patients affected by IPF.

Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a severe progressive interstitial lung disease. At 5-year follow-up, 15% of IPF patients develop lung cancer, which significantly reduces the survival rate. Here we review the literature on the clinical role of oncomarkers in IPF progression, and describe the trend of routine oncomarkers in IPF patients over the longest follow-up yet reported. Materials and methods: A systematic search of the literature in PubMed was performed to find relevant studies published up to 24 September 2020. The most common oncomarkers were chosen to select papers related to pulmonary fibrosis. Then, 24 IPF patients and 25 non-IPF patients, followed at Careggi ILD Referral Centre and Siena Regional Referral Centre for ILD, were enrolled consecutively. Results: A few studies reported an association between serum oncomarkers and severity of IPF. NSE, CEA, Ca19.9, and Ca125 were higher in the IPF, than in the non-IPF, group at every follow-up (p < 0.05). Ca15.3 concentrations were higher in the IPF, than the non-IPF, group at t3 (p = 0.0080) and t4 (p = 0.0168). To improve the specificity and sensitivity of Ca15.3, a panel of biomarkers was analyzed, with the IPF group as dependent variable, and chitotriosidase, Cyfra 21.1, Ca15.3, Ca125, and Ca19.9 as independent variables. Conclusions: This study focused on the discovery of multiple biomarker signatures, such as combinations of oncomarkers, that are widely and routinely available in biochemistry laboratories. The combination of clinical parameters and biological markers could help achieve more accurate results regarding prognosis and response to treatment in IPF. Our results could pave the way for a more “personalized” medical approach to patients affected by IPF.

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.

Current perspectives on the immunopathogenesis of sarcoidosis

Sarcoidosis is an inflammatory systemic disease that commonly affects the lungs or lymph nodes but can manifest in other organs. Herein, we review the latest evidence establishing how innate and adaptive immune responses contribute to the pathogenesis and clinical course of sarcoidosis. We discuss the possible role of microbial organisms as etiologic agents in sarcoidosis and the evidence supporting sarcoidosis as an autoimmune disease. We also discuss how animal and in vitro human models have advanced our understanding of the immunopathogenesis of sarcoidosis. Finally, we discuss therapeutics for sarcoidosis and the effects on the immune system.

Metabolic Dysregulation in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disorder limited to the lung. New findings, starting from our proteomics studies on IPF, suggest that systemic involvement with altered molecular mechanisms and metabolic disorder is an underlying cause of fibrosis. The role of metabolic dysregulation in the pathogenesis of IPF has not been extensively studied, despite a recent surge of interest. In particular, our studies on bronchoalveolar lavage fluid have shown that the renin–angiotensin–aldosterone system (RAAS), the hypoxia/oxidative stress response, and changes in iron and lipid metabolism are involved in onset of IPF. These processes appear to interact in an intricate manner and to be related to different fibrosing pathologies not directly linked to the lung environment. The disordered metabolism of carbohydrates, lipids, proteins and hormones has been documented in lung, liver, and kidney fibrosis. Correcting these metabolic alterations may offer a new strategy for treating fibrosis. This paper focuses on the role of metabolic dysregulation in the pathogenesis of IPF and is a continuation of our previous studies, investigating metabolic dysregulation as a new target for fibrosis therapy.

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.

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.

T Cells in Fibrosis and Fibrotic Diseases

Fibrosis is the extensive deposition of fibrous connective tissue, and it is characterized by the accumulation of collagen and other extracellular matrix (ECM) components. Fibrosis is essential for wound healing and tissue repair in response to a variety of triggers, which include infection, inflammation, autoimmune disorder, degenerative disease, tumor, and injury. Fibrotic remodeling in various diseases, such as liver cirrhosis, pulmonary fibrosis, renal interstitial fibrosis, myocardial infarction, systemic sclerosis (SSc), and graft-versus-host disease (GVHD), can impair organ function, causing high morbidity and mortality. Both innate and adaptive immunity are involved in fibrogenesis. Although the roles of macrophages in fibrogenesis have been studied for many years, the underlying mechanisms concerning the manner in which T cells regulate fibrosis are not completely understood. The T cell receptor (TCR) engages the antigen and shapes the repertoire of antigen-specific T cells. Based on the divergent expression of surface molecules and cell functions, T cells are subdivided into natural killer T (NKT) cells, γδ T cells, CD8⁺ cytotoxic T lymphocytes (CTL), regulatory T (Treg) cells, T follicular regulatory (Tfr) cells, and T helper cells, including Th1, Th2, Th9, Th17, Th22, and T follicular helper (Tfh) cells. In this review, we summarize the pro-fibrotic or anti-fibrotic roles and distinct mechanisms of different T cell subsets. On reviewing the literature, we conclude that the T cell regulations are commonly disease-specific and tissue-specific. Finally, we provide perspectives on microbiota, viral infection, and metabolism, and discuss the current advancements of technologies for identifying novel targets and developing immunotherapies for intervention in fibrosis and fibrotic diseases.

BAL and serum multiplex lipid profiling in idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis

BACKGROUND

Differential diagnosis between IPF and fibrotic HP (fHP) can be challenging: these two ILDs share many common features but call for different therapeutic approaches. In the present study, differential lipid mediator profiles were analysed by a new method in BAL and serum from HP and IPF patients.

MATERIALS AND METHODS

76 patients were enrolled retrospectively in the study. Median age (IQR) was 67 years (51-74); 63% were males, 30 had fHP and 46 had IPF. Serum and BAL samples were collected at initial diagnosis. For quantification of serum and BAL lipid mediators was used bead-based multiplex LEGENDPlex™ analysis (Biolegend).

RESULTS

Serum Apo A1 levels were significantly higher in IPF than fHP patients (p = 0.314); indeed, serum levels of CCL2 and Apo C3 were lower in HP than in IPF patients (p = 0.013 and p = 0.041, respectively). BAL concentrations of Apo A1, adipsin, Apo C3 and APN were significantly lower in IPF than in fHP patients (p < 0.0001, p < 0.0001, p = 0.007 and p = 0.023, respectively). In the logistic regression, IPF was tested as dependent variable. Serum levels of Apo A1, CCL2 and Apo C3 were tested as independent variables and ROC curve analysis of model performance showed AUC 93% (p < 0.0001); on the other hand, BAL concentrations of Apo A1, adipsin, Apo C3 and APN showed AUC 81% (p < 0.0001).

DISCUSSION

Lipid biomarkers evaluated in BAL in our study confirm the hypothesis that fHP and IPF have different lung fibrosis phenotypes. The former is a post-inflammatory cell-regulated ILD and the second is more related to tissue remodeling and repair.

Neutrophil-to-lymphocyte ratio in bronchoalveolar lavage from IPF patients: a novel prognostic biomarker?

BACKGROUND

This is the first time that a bronchoalveolar lavage (BAL) neutrophil-to-lymphocyte ratio (NL-ratio) has been demonstrated in sarcoidosis and chronic Hypersensitivity Pneumonitis (cHP) than in idiopathic pulmonary fibrosis (IPF) patients.

SUBJECTS AND METHODS

Consecutive BAL samples from the 167 interstitial lung disease (ILD) patients were retrospectively enrolled in the study and clustered into three diagnostic categories: IPF, cHP and sarcoidosis.

RESULTS

NL-ratio which proved higher in IPF (mean±SD, 2.1±3.8) than sarcoidosis (mean±SD 0.7±1.9; p<1E-04) and cHP patients (mean±SD 1.6±3.1; p=7.7E-03). ROC curve analysis to discriminate between Sarcoidosis and other ILDs showed an area under the curve (AUC) of 83.7%, (56% sensitivity and 96% specificity) while IPF and the other ILD were discriminated with AUC of 73% using a NL-ratio threshold value of 0.48 (73% sensitivity and 63% specificity). Interestingly, the NL-ratio was significantly correlated with other prognostic parameters: it was inversely correlated with forced vital capacity (FVC) (r=-0.3; p=2.5E-02) and forced expiration volume in 1 second (FEV1) (r=-0.3; p=2E-02) percentages and directly correlated with composite pulmonary index (CPI) score (r=0.3; p=3.2E-02). A decision-tree statistical algorithm was applied.

CONCLUSIONS

This is the first time that a lower NL-ratio has been demonstrated in sarcoidosis and cHP than in IPF patients. The present preliminary report indicates a relationship between BAL NL- ratio and lung function parameters in patients with IPF: this ratio may help to optimize management of IPF patients and to improve follow-up and outcome.

Angiopoietin-like protein 2 as a novel marker for patients with primary Sjogren's syndrome-related interstitial lung disease

Angiopoietin-like protein 2 (Angptl2) plays a key role in chronic inflammation and tissue remodeling. We evaluated whether serum Angptl2 is associated with interstitial lung disease (ILD) in primary Sjogren's syndrome (pSS) patients. A total of 158 consecutive pSS patients and 25 normal healthy controls, which completed lung HRCT, were enrolled in our research. The levels of serum Angptl2 and TGF-β1 were measured by enzyme-linked immunosorbent assay. We investigated the correlation between the activity indexes of pSS-ILD patients and the serum Angptl2 levels. There were 71 of 158 (44.94%) patients interpreted pSS-ILD by radiologists at the initial presentation. The median interquartile range for serum Angptl2 was 16.55 ng/mL (range 10.82-41.07) in pSS patients, compared with 6.05 ng/mL (range 3.53-9.91) in normal healthy controls (P < 0.001). Importantly, differences between Angptl2 levels in pSS-ILD patients and pSS-N-ILD patients were also statistically significant [29.80 ng/mL (range 15.42-54.40), 14.75 ng/mL (range 9.85-40.48), P < 0.001]. A logistic regression analysis suggested that anti-Ro52, serum Angptl2 and DLCO were associated with pSS patients with interstitial lung disease, with aORs and 95% CIs of 2.06 (1.14-7.65), 4.13 (1.25-15.89) and 9.51 (2.10-37.74), respectively. Moreover, anti-Ro52 (r_s = 0.48, P = 0.016) and TGF-β1 (r_s = 0.64, P = 0.003) were significantly correlated with the serum Angptl2 in pSS-ILD patients. And, in pulmonary function tests, the serum Angptl2 was significantly correlated with DLCO (r_s = - 0.40, P = 0.009) and FVC (r_s = -0.37, P = 0.020). Serum Angptl2 may display a peculiar role in the pathogenesis of pSS-ILD and might be a potential biomarker.

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.