Increased monocyte count as a cellular biomarker for poor outcomes in fibrotic diseases: a retrospective, multicentre cohort study

Idiopathic pulmonary fibrosis (IPF): Diagnostic routes using novel biomarkers

Idiopathic pulmonary fibrosis (IPF) diagnosis is still the diagnosis of exclusion. Differentiating from other forms of interstitial lung diseases (ILDs) is essential, given the various therapeutic approaches. The IPF course is now unpredictable for individual patients, although some genetic factors and several biomarkers have already been associated with various IPF prognoses. Since its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. The present review critically examines the recent literature on molecular biomarkers potentially useful in IPF diagnostics. The examined biomarkers are grouped into breath and sputum biomarkers, serologically assessed extracellular matrix neoepitope markers, and oxidative stress biomarkers in lung tissue. Fibroblasts and complete blood count have also gained recent interest in that respect. Although several biomarker candidates have been profiled, there has yet to be a single biomarker that proved specific to the IPF disease. Nevertheless, various IPF biomarkers have been used in preclinical and clinical trials to verify their predictive and monitoring potential.

The interplay of Cxcl10+/Mmp14+ monocytes and Ccl3+ neutrophils proactively mediates silica-induced pulmonary fibrosis

As a fatal occupational disease with limited therapeutic options, molecular mechanisms underpinning silicosis are still undefined. Herein, single-cell RNA sequencing of the lung tissue of silicosis mice identified two monocyte subsets, which were characterized by Cxcl10 and Mmp14 and enriched in fibrotic mouse lungs. Both Cxcl10+ and Mmp14+ monocyte subsets exhibited activation of inflammatory marker genes and positive regulation of cytokine production. Another fibrosis-unique neutrophil population characterized by Ccl3 appeared to be related to the pro-fibrotic process, specifically the "inflammatory response". Meanwhile, the proportion of monocytes and neutrophils was significantly higher in the serum of silicosis patients and slices of lung tissue from patients with silicosis further validated the over-expression of Cxcl10 and Mmp14 in monocytes, also Ccl3 in neutrophils, respectively. Mechanically, receptor-ligand interaction analysis identified the crosstalk of Cxcl10+/Mmp14+ monocytes with Ccl3+ neutrophils promoting fibrogenesis via coupling of HBEGF-CD44 and CSF1-CSF1R. In vivo, administration of clodronate liposomes, Cxcl10 or Mmp14 siRNA-loaded liposomes, Ccl3 receptor antagonist BX471, CD44 or CSF1R neutralizing antibodies significantly alleviated silica-induced lung fibrosis. Collectively, these results demonstrate that the newly defined Cxcl10+/Mmp14+ monocytes and Ccl3+ neutrophils participate in the silicosis process and highlight anti-receptor-ligand pair treatment as a potentially effective therapeutic strategy in managing silicosis.

Baseline absolute monocyte count predicts lung function decline among patients with systemic sclerosis-associated interstitial lung disease: A post hoc analysis from the focuSSced trial

OBJECTIVE

Interstitial lung disease (ILD) is the leading cause of death in adults with systemic sclerosis (SSc). The identification of biomarkers to predict progression of SSc-ILD is an important unmet need. The purpose of this study was to determine whether an elevated baseline absolute monocyte count (AMC) is associated with a decline in forced vital capacity (FVC) at 48 weeks among participants with SSc-ILD enrolled in the phase 3 focuSSced trial.

METHODS

We performed a post-hoc analysis of the focuSSced trial, a multicenter, double-blind, randomized, placebo-controlled trial of adults with diffuse cutaneous SSc for ≤ 60 months. Participants received subcutaneous tocilizumab 162 mg or placebo weekly for 48 weeks. We examined the relationship between baseline AMC and FVC at 48 weeks using a General Linear Model adjusted for potential confounders.

RESULTS

The 136 participants with SSc-ILD in focuSSced were included in this study. Among participants assigned to the placebo group, there was a statistically significant inverse association between baseline AMC and change in FVC from baseline at week 48 in both unadjusted (β coefficient -0.539, 95 % CI -1.032 to -0.047, p-value=0.032) and multivariable-adjusted (β coefficient -0.573, 95 % CI -1.086 to -0.060, p-value=0.029) models. Among participants with SSc-ILD assigned to the tocilizumab group, there was no statistically significant association between baseline AMC and change in FVC from baseline at week 48 in unadjusted or fully adjusted models.

CONCLUSION

AMC may be a biomarker of disease progression in SSc-ILD, especially in those with early SSc with elevated circulating inflammatory markers. These results should be validated in other SSc-ILD cohorts.

Effects of Anti-Fibrotic Drugs on Transcriptome of Peripheral Blood Mononuclear Cells in Idiopathic Pulmonary Fibrosis

Two anti-fibrotic drugs, pirfenidone (PFD) and nintedanib (NTD), are currently used to treat idiopathic pulmonary fibrosis (IPF). Peripheral blood mononuclear cells (PBMCs) are immunocompetent cells that could orchestrate cell-cell interactions associated with IPF pathogenesis. We employed RNA sequencing to examine the transcriptome signature in the bulk PBMCs of patients with IPF and the effects of anti-fibrotic drugs on these signatures. Differentially expressed genes (DEGs) between "patients with IPF and healthy controls" and "before and after anti-fibrotic treatment" were analyzed. Enrichment analysis suggested that fatty acid elongation interferes with TGF-β/Smad signaling and the production of oxidative stress since treatment with NTD upregulates the fatty acid elongation enzymes ELOVL6. Treatment with PFD downregulates COL1A1, which produces wound-healing collagens because activated monocyte-derived macrophages participate in the production of collagen, type I, and alpha 1 during tissue damage. Plasminogen activator inhibitor-1 (PAI-1) regulates wound healing by inhibiting plasmin-mediated matrix metalloproteinase activation, and the inhibition of PAI-1 activity attenuates lung fibrosis. DEG analysis suggested that both the PFD and NTD upregulate SERPINE1, which regulates PAI-1 activity. This study embraces a novel approach by using RNA sequencing to examine PBMCs in IPF, potentially revealing systemic biomarkers or pathways that could be targeted for therapy.

Acute exacerbation of idiopathic pulmonary fibrosis disease: a diagnosis model in China

OBJECTIVE

To develop and validate a diagnosis model to inform risk stratified decisions for idiopathic pulmonary fibrosis patients experiencing acute exacerbations (AE-IPF).

METHODS

In this retrospective cohort study performed from 1 January 2016 to 31 December 2022, we used data from the West China Hospital of Sichuan University for model development and validation. Blood test results and the underlying diseases of patients were collected through the HIS system and LIS system. An algorithm for filtering candidate variables based on least absolute shrinkage and selection operator (LASSO) regression. Logistic regression was performed to develop the risk model. Multiple imputation handled missing predictor data. Model performance was assessed through calibration and diagnostic odds ratio.

RESULTS

311 and 133 participants were included in the development and validation cohorts, respectively. 3 candidate predictors (29 parameters) were included. A logistic regression analysis revealed that dyspnea, percentage of CD4+  T-lymphocytes, and percentage of monocytes are independent risk factors for AE-IPF. Nomographic model was constructed using these independent risk factors, and the C-index was 0.69. For internal validation, the C-index was 0.69, and that indicated good accuracy. Diagnostic odds ratio was 5.40. Meanwhile, in mild, moderate, and severe subgroups, AE positivity rates were 0.37, 0.47, and 0.81, respectively. The diagnostic model can classify patients with AE-IPF into different risk classes based on dyspnea, percentage of CD4+  T-lymphocytes, and percentage of monocytes.

CONCLUSION

A diagnosis model was developed and validated that used information collected from HIS system and LIS system and may be used to risk stratify idiopathic pulmonary fibrosis patients experiencing acute exacerbations.

Mast-cell expressed membrane protein-1 is expressed in classical monocytes and alveolar macrophages in idiopathic pulmonary fibrosis and regulates cell chemotaxis, adhesion, and migration in a TGFβ-dependent manner

Mast-cell expressed membrane protein-1 (MCEMP1) is higher in patients with idiopathic pulmonary fibrosis (IPF) with an increased risk of death. Here we aimed to establish the mechanistic role of MCEMP1 in pulmonary fibrosis. We identified increased MCEMP1 expression in classical monocytes and alveolar macrophages in IPF compared with controls. MCEMP1 is upregulated by transforming growth factor beta (TGFβ) at the mRNA and protein levels in monocytic leukemia THP-1 cells. TGFβ-mediated MCEMP1 upregulation results from the cooperation of SMAD3 and SP1 via concomitant binding to SMAD3/SP1 cis-regulatory elements within the MCEMP1 promoter. We also found that MCEMP1 regulates TGFβ-mediated monocyte chemotaxis, adhesion, and migration. Our results suggest that MCEMP1 may regulate the migration and transition of monocytes to monocyte-derived alveolar macrophages during pulmonary fibrosis development and progression.NEW & NOTEWORTHY MCEMP1 is highly expressed in circulating classical monocytes and alveolar macrophages in IPF, is regulated by TGFβ, and participates in the chemotaxis, adhesion, and migration of circulating monocytes by modulating the effect of TGFβ in RHO activity.

Neutrophil-lymphocyte ratio being associated with mortality risk in patients receiving antifibrotic therapy

BACKGROUND

Antifibrotic therapy is widely used for patients with progressive fibrotic interstitial lung disease (ILD), regardless of etiology. There is an urgent need for a simple, inexpensive, and repeatable biomarker to evaluate disease severity and mortality risk.

METHODS

This retrospective multicohort study assessed the neutrophil-lymphocyte ratios (NLRs) of 416 patients with ILD who received antifibrotic therapy (Hamamatsu cohort, n = 217; Seirei cohort, n = 199). The mortality risk vs. NLR relationship was evaluated at therapy initiation and 1 year. The optimal NLR cutoff of 2.7 was selected according to the mortality risk.

RESULTS

Survival was shorter in patients with high NLR than with low NLR (median: 2.63 vs. 4.01 years). The NLR classification results (cutoff: 2.7) were longitudinally preserved in >70 % of the patients, and patients with consistently high NLR had a higher risk of mortality than others (median, 2.97 vs. 4.42 years). In multivariate analysis, high NLR was significantly associated with mortality independent of age, sex, forced vital capacity, lung diffusing capacity for carbon monoxide (DLCO), or the gender-age-physiology (GAP) index. A combined GAP index-NLR assessment classified mortality risk into four groups. Subset analyses revealed that NLR assessment was more applicable to patients without advanced disease, not taking steroids, and with idiopathic pulmonary fibrosis (IPF) than to patients with advanced disease, taking steroids, and patients with Non-IPF.

CONCLUSION

High NLR was associated with an increased mortality risk in patients with ILDs receiving antifibrotic therapy. Assessment of NLR may help predict disease severity and mortality risk in antifibrotic therapy.

Association of Monocyte Count With Lung Function and Exercise Capacity Among Hospitalized COVID-19 Survivors: A 2-Year Cohort Study

BACKGROUND

Abnormal changes of monocytes have been observed in acute COVID-19, whereas associations of monocyte count with long COVID were not sufficiently elucidated.

METHODS

A cohort study was conducted among COVID-19 survivors discharged from hospital. The primary outcomes were core symptoms of long COVID, distance walked in 6 min, and lung function, and the secondary outcomes were health-related quality of life and healthcare use after discharge. Latent variable mixture modeling was used to classify individuals into groups with similar trajectory of monocyte count from discharge to 2-year after symptom onset. Multivariable adjusted generalized linear regression models and logistic regression models were used to estimate the associations of monocyte count trajectories and monocyte count at discharge with outcomes.

RESULTS

In total, 1389 study participants were included in this study. Two monocyte count trajectories including high to normal high and normal trajectory were identified. After multivariable adjustment, participants in high to normal high trajectory group had an odds ratio (OR) of 2.52 (95% CI, 1.44-4.42) for smell disorder, 2.27 (1.27-4.04) for 6-min walking distance less than lower limit of normal range, 2.45 (1.08-5.57) for total lung capacity (TLC) < 80% of predicted, 3.37 (1.16-9.76) for personal care problem, and 1.70 (1.12-2.58) for rehospitalization after discharge at 2-year follow-up compared with those in normal trajectory group. Monocyte count at discharge showed similar results, which was associated with smell disorder, TLC < 80% of predicted, diffusion impairment, and rehospitalization.

CONCLUSIONS

Monocyte count may serve as an easily accessible marker for long-term management of people recovering from COVID-19.

Activation of the P2RX7/IL-18 pathway in immune cells attenuates lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is an aggressive interstitial lung disease associated with progressive and irreversible deterioration of respiratory functions that lacks curative therapies. Despite IPF being associated with a dysregulated immune response, current antifibrotics aim only at limiting fibroproliferation. Transcriptomic analyses show that the P2RX7/IL18/IFNG axis is downregulated in IPF patients and that P2RX7 has immunoregulatory functions. Using our positive modulator of P2RX7, we show that activation of the P2RX7/IL-18 axis in immune cells limits lung fibrosis progression in a mouse model by favoring an antifibrotic immune environment, with notably an enhanced IL-18-dependent IFN-γ production by lung T cells leading to a decreased production of IL-17 and TGFβ. Overall, we show the ability of the immune system to limit lung fibrosis progression by targeting the immunomodulator P2RX7. Hence, treatment with a small activator of P2RX7 may represent a promising strategy to help patients with lung fibrosis.

Expansion of distinct peripheral blood myeloid cell subpopulations in patients with rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

Interstitial lung disease (ILD) is associated with significant mortality in rheumatoid arthritis (RA) patients with key cellular players remaining largely unknown. This study aimed to characterize inflammatory and myeloid derived suppressor cell (MDSC) subpopulations in RA-ILD as compared to RA, idiopathic pulmonary fibrosis (IPF) without autoimmunity, and controls.

METHODS

Peripheral blood was collected from patients with RA, RA-ILD, IPF, and controls (N = 60, 15/cohort). Myeloid cell subpopulations were identified phenotypically by flow cytometry using the following markers:CD45,CD3,CD19,CD56,CD11b,HLA-DR,CD14,CD16,CD15,CD125,CD33. Functionality of subsets were identified with intracellular arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS) expression.

RESULTS

There was increased intermediate (CD14++CD16+) and nonclassical (CD14+/-CD16++) and decreased classical (CD14++CD16-) monocytes in RA, RA-ILD, and IPF vs. control. Intermediate monocytes were higher and classical monocytes were lower in RA-ILD vs. RA but not IPF. Monocytic (m)MDSCs were higher in RA-ILD vs. control and RA but not IPF. Granulocytic (g)MDSCs did not significantly differ. In contrast, neutrophils were increased in IPF and RA-ILD patients with elevated expression of Arg-1 sharing similar dimensional clustering pattern. Eosinophils were increased in RA-ILD vs. controls, RA and IPF. Across cohorts, iNOS was decreased in intermediate/nonclassical monocytes but increased in mMDSCs vs. classical monocytes. In RA-ILD, iNOS positive mMDSCs were increased versus classic monocytes.

CONCLUSIONS

Myeloid cell subpopulations are significantly modulated in RA-ILD patients with expansion of CD16+ monocytes, mMDSCs, and neutrophils, a phenotypic profile more aligned with IPF than other RA patients. Eosinophil expansion was unique to RA-ILD, potentially facilitating disease pathogenesis and providing a future therapeutic target.

High-dimensional comparison of monocytes and T cells in post-COVID and idiopathic pulmonary fibrosis

Introduction

Up to 30% of hospitalized COVID-19 patients experience persistent sequelae, including pulmonary fibrosis (PF).

Methods

We examined COVID-19 survivors with impaired lung function and imaging worrisome for developing PF and found within six months, symptoms, restriction and PF improved in some (Early-Resolving COVID-PF), but persisted in others (Late-Resolving COVID-PF). To evaluate immune mechanisms associated with recovery versus persistent PF, we performed single-cell RNA-sequencing and multiplex immunostaining on peripheral blood mononuclear cells from patients with Early- and Late-Resolving COVID-PF and compared them to age-matched controls without respiratory disease.

Results and discussion

Our analysis showed circulating monocytes were significantly reduced in Late-Resolving COVID-PF patients compared to Early-Resolving COVID-PF and non-diseased controls. Monocyte abundance correlated with pulmonary function forced vital capacity and diffusion capacity. Differential expression analysis revealed MHC-II class molecules were upregulated on the CD8 T cells of Late-Resolving COVID-PF patients but downregulated in monocytes. To determine whether these immune signatures resembled other interstitial lung diseases, we analyzed samples from Idiopathic Pulmonary Fibrosis (IPF) patients. IPF patients had a similar marked decrease in monocyte HLA-DR protein expression compared to Late-Resolving COVID-PF patients. Our findings indicate decreased circulating monocytes are associated with decreased lung function and uniquely distinguish Late-Resolving COVID-PF from Early-Resolving COVID-PF, IPF, and non-diseased controls.

Therapeutic strategies to target connective tissue growth factor in fibrotic lung diseases

The treatment of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF), remains challenging as current available antifibrotic agents are not effective in halting disease progression. Connective tissue growth factor (CTGF), also known as cellular communication factor 2 (CCN2), is a member of the CCN family of proteins that regulates cell signaling through cell surface receptors such as integrins, the activity of cytokines/growth factors, and the turnover of extracellular matrix (ECM) proteins. Accumulating evidence indicates that CTGF plays a crucial role in promoting lung fibrosis through multiple processes, including inducing transdifferentiation of fibroblasts to myofibroblasts, epithelial-mesenchymal transition (EMT), and cooperating with other fibrotic mediators such as TGF-β. Increased expression of CTGF has been observed in fibrotic lungs and inhibiting CTGF signaling has been shown to suppress lung fibrosis in several animal models. Thus, the CTGF signaling pathway is emerging as a potential therapeutic target in IPF and other pulmonary fibrotic conditions. This review provides a comprehensive overview of the current evidence on the pathogenic role of CTGF in pulmonary fibrosis and discusses the current therapeutic agents targeting CTGF using a systematic review approach.

Serum heme oxygenase-1 as a prognostic biomarker in patients with acute exacerbation of interstitial lung disease

Serum heme oxygenase (HO)-1 level has been reported as a clinically reliable diagnostic biomarker for acute exacerbation of interstitial lung disease (ILD); however, its utility for predicting mortality among these patients is unclear. Serum HO-1 levels of patients newly diagnosed with acute exacerbation of ILD were measured at the time of initiating steroid pulse therapy. The relationship between serum HO-1 and various other serum biomarkers, change in HRCT findings, and disease prognosis at 12 weeks after diagnosis of acute exacerbation was evaluated in 51 patients, of whom 17 (33%) had idiopathic pulmonary fibrosis (IPF). Serum HO-1 was higher in patients with acute exacerbation of IPF than in patients with acute exacerbation of other ILDs. Serum HO-1 levels were higher in patients who died within these 12 weeks than in survivors. Among age, sex, comorbidities, IPF diagnosis, HRCT findings, and blood biomarkers, serum HO-1 was a primary predictor of 12-week mortality. In 41 patients who underwent repeat HRCT, serum HO-1 was higher in patients with honeycomb progression than in those without. Serum HO-1 measurement could be useful for evaluating disease mortality and morbidity of patients with acute exacerbation of ILDs.

Neutrophil-lymphocyte ratio in patients with idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (iPPFE), a progressive fibrotic disease, is characterised by upper lobe-dominant lung fibrosis involving the pleura and subpleural lung parenchyma. However, no prognostic markers have been established for this condition. Associations between blood leucocyte levels and mortality have been reported in patients with idiopathic pulmonary fibrosis; therefore, we hypothesised that peripheral leucocyte levels are associated with mortality risk in patients with iPPFE.

METHODS

This retrospective study longitudinally assessed peripheral leucocyte counts at the time of diagnosis and 1 year after diagnosis in two cohorts of 127 patients with iPPFE (69 and 58 patients in Seirei and Hamamatsu cohorts, respectively).

RESULTS

A comprehensive assessment of peripheral leucocytes revealed that the neutrophil-lymphocyte ratio (NLR) was associated with mortality in patients with iPPFE after adjusting for age, sex and forced vital capacity in multivariate analyses (adjusted HR, 1.131; 95% CI, 1.032 to 1.227). When the patients were classified based on the median NLR, those with a high NLR had shorter survival than those with a low NLR (median, 32.2 vs 79.8 months; HR, 2.270; 95% CI, 1.416 to 3.696). Interestingly, the results of the NLR classification by median were longitudinally preserved in >70% of patients, and patients with consistently high NLR were at a higher risk of mortality than others (median, 24.8 vs 79.6 months; HR, 3.079; 95% CI, 1.878 to 5.031). Compared with the gender-age-physiology model, a composite model comprising age, sex and NLR could successfully stratify patients with iPPFE into three groups according to mortality risk.

CONCLUSION

The assessment of peripheral leucocyte counts is easy and might be useful in evaluating disease severity and mortality risk in patients with iPPFE. Our study suggests the importance of focusing on peripheral leucocyte levels in daily practice.

Pulmonary fibrosis: from pathogenesis to clinical decision-making

Pulmonary fibrosis (PF) encompasses a spectrum of chronic lung diseases that progressively impact the interstitium, resulting in compromised gas exchange, breathlessness, diminished quality of life (QoL), and ultimately respiratory failure and mortality. Various diseases can cause PF, with their underlying causes primarily affecting the lung interstitium, leading to their referral as interstitial lung diseases (ILDs). The current understanding is that PF arises from abnormal wound healing processes triggered by various factors specific to each disease, leading to excessive inflammation and fibrosis. While significant progress has been made in understanding the molecular mechanisms of PF, its pathogenesis remains elusive. This review provides an in-depth exploration of the latest insights into PF pathophysiology, diagnosis, treatment, and future perspectives.

Myeloid Heterogeneity Mediates Acute Exacerbations of Pulmonary Fibrosis

Epidemiological evidence indicates that exposure to particulate matter is linked to the development of idiopathic pulmonary fibrosis (IPF) and increases the incidence of acute exacerbations of IPF. In addition to accelerating the rate of lung function decline, exposure to fine particulate matter (particulate matter smaller than 2.5 μm [PM2.5]) is a risk factor for increased mortality in subjects with IPF. In this article, we show that exposure to PM2.5 mediates monocyte recruitment and fibrotic progression in mice with established fibrosis. In mice with established fibrosis, bronchoalveolar lavage cells showed monocyte/macrophage heterogeneity after exposure to PM2.5. These cells had a significant inflammatory and anti-inflammatory signature. The mixed heterogeneity of cells contributed to the proinflammatory and anti-inflammatory response. Although monocyte-derived macrophages were recruited to the lung in bleomycin-injured mice treated with PM2.5, recruitment of monocytes expressing Ly6Chi to the lung promoted progression of fibrosis, reduced lung aeration on computed tomography, and impacted lung compliance. Ly6Chi monocytes isolated from PM2.5-exposed fibrotic mice showed enhanced expression of proinflammatory markers compared with fibrotic mice exposed to vehicle. Moreover, IPF bronchoalveolar lavage cells treated ex vivo with PM2.5 showed an exaggerated inflammatory response. Targeting Ly6Chi monocyte recruitment inhibited fibrotic progression in mice. Moreover, the adoptive transfer of Ly6Chi monocytes exacerbated established fibrosis. These observations suggest that enhanced recruitment of Ly6Chi monocytes with a proinflammatory phenotype mediates acute exacerbations of pulmonary fibrosis, and targeting these cells may provide a potential novel therapeutic target to protect against acute exacerbations of IPF.

Monoclonal enolase-1 blocking antibody ameliorates pulmonary inflammation and fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal disease with limited therapeutic options. The infiltration of monocytes and fibroblasts into the injured lungs is implicated in IPF. Enolase-1 (ENO1) is a cytosolic glycolytic enzyme which could translocate onto the cell surface and act as a plasminogen receptor to facilitate cell migration via plasmin activation. Our proprietary ENO1 antibody, HL217, was screened for its specific binding to ENO1 and significant inhibition of cell migration and plasmin activation (patent: US9382331B2).

METHODS

In this study, effects of HL217 were evaluated in vivo and in vitro for treating lung fibrosis.

RESULTS

Elevated ENO1 expression was found in fibrotic lungs in human and in bleomycin-treated mice. In the mouse model, HL217 reduced bleomycin-induced lung fibrosis, inflammation, body weight loss, lung weight gain, TGF-β upregulation in bronchial alveolar lavage fluid (BALF), and collagen deposition in lung. Moreover, HL217 reduced the migration of peripheral blood mononuclear cells (PBMC) and the recruitment of myeloid cells into the lungs. In vitro, HL217 significantly reduced cell-associated plasmin activation and cytokines secretion from primary human PBMC and endothelial cells. In primary human lung fibroblasts, HL217 also reduced cell migration and collagen secretion.

CONCLUSIONS

These findings suggest multi-faceted roles of cell surface ENO1 and a potential therapeutic approach for pulmonary fibrosis.

Mast-Cell Expressed Membrane Protein-1 (MCEMP1) is expressed in classical monocytes and alveolar macrophages in Idiopathic Pulmonary Fibrosis and regulates cell chemotaxis, adhesion, and migration in a TGFβ dependent manner

Background

Mast-Cell Expressed Membrane Protein-1 (MCEMP1) is higher in Idiopathic Pulmonary Fibrosis (IPF) patients with increased risk of death and poor outcomes. Here we seek to establish the mechanistic role of MCEMP1 in pulmonary fibrosis.

Methods

MCEMP1 expression was analyzed by single-cell RNA sequencing, immunofluorescence in Peripheral Blood Mononuclear Cells (PBMC) as well as in lung tissues from IPF patients and controls. Chromatin Immunoprecipitation (ChiP) and Proximity Ligation Assay (PLA) were used to study the transcriptional regulation of MCEMP1 . Transient RNA interference and lentivirus transduction were used to knockdown and knock-in MCEMP1 in THP-1 cells to study chemotaxis, adhesion, and migration. Bulk RNA sequencing was used to identify the mechanisms by which MCEMP1 participates in monocyte function. Active RHO pull-down assay was used to validate bulk RNA sequencing results.

Results

We identified increased MCEMP1 expression in classical monocytes and alveolar macrophages in IPF compared to controls. MCEMP1 was upregulated by TGFβ at the mRNA and protein levels in THP-1. TGFβ-mediated MCEMP1 upregulation results from the cooperation of SMAD3 and SP1 via concomitant binding to SMAD3/SP1 cis -regulatory elements within the MCEMP1 promoter. In terms of its function, we found that MCEMP1 regulates TGFβ-mediated monocyte chemotaxis, adhesion, and migration. 400 differentially expressed genes were found to increase after TGFβ stimulation of THP-1, further increased in MCEMP1 knock-in cells treated with TGFβ and decreased in MCEMP1 knockdown cells treated with TGFβ. GO annotation analysis of these genes showed enrichment for positive regulation of RHO GTPase activity and signal transduction. While TGFβ enhanced RHO GTPase activity in THP-1 cells, this effect was attenuated following MCEMP1 knockdown.

Conclusion

MCEMP1 is highly expressed in circulating classical monocytes and alveolar macrophages in IPF. MCEMP1 is regulated by TGFβ and participates in the chemotaxis, adhesion, and migration of circulating monocytes by modulating the effect of TGFβ in RHO activity. Our results suggest that MCEMP1 may regulate the migration and transition of monocytes to monocyte-derived alveolar macrophages during pulmonary fibrosis development and progression.

Neutrophil levels correlate with quantitative extent and progression of fibrosis in IPF: results of a single-centre cohort study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with poor prognosis. Clinical studies have demonstrated association between different blood leucocytes and mortality and forced vital capacity (FVC) decline. Here, we question which blood leucocyte levels are specifically associated with progression of fibrosis, measured by accumulation of fibrosis on CT scan using a standardised automated method.

METHODS

Using the Computer-Aided Lung Informatics for Pathology Evaluation and Rating CT algorithm, we determined the correlation between different blood leucocytes (<4 months from CT) and total lung fibrosis (TLF) scores, pulmonary vessel volume (PVV), FVC% and transfer factor of lung for carbon monoxide% at baseline (n=171) and with progression of fibrosis (n=71), the latter using multivariate Cox regression.

RESULTS

Neutrophils (but not monocyte or lymphocytes) correlated with extent of lung fibrosis (TLF/litre) (r=0.208, p=0.007), PVV (r=0.259, p=0.001), FVC% (r=-0.127, p=0.029) at baseline. For the 71 cases with repeat CT; median interval between CTs was 25.9 (16.8-39.9) months. Neutrophil but not monocyte levels are associated with increase in TLF/litre (HR 2.66, 95% CI 1.35 to 5.25, p=0.005).

CONCLUSION

Our study shows that neutrophil rather than monocyte levels correlated with quantifiable increase in fibrosis on imaging of the lungs in IPF, suggesting its relative greater contribution to progression of fibrosis in IPF.

Combining Clinical and Biological Data to Predict Progressive Pulmonary Fibrosis in Patients With Systemic Sclerosis Despite Immunomodulatory Therapy

OBJECTIVE

Progressive pulmonary fibrosis (PPF) is the leading cause of death in systemic sclerosis (SSc). This study aimed to develop a clinical prediction nomogram using clinical and biological data to assess risk of PPF among patients receiving treatment of SSc-related interstitial lung disease (SSc-ILD).

METHODS

Patients with SSc-ILD who participated in the Scleroderma Lung Study II (SLS II) were randomized to treatment with either mycophenolate mofetil (MMF) or cyclophosphamide (CYC). Clinical and biological parameters were analyzed using univariable and multivariable logistic regression, and a nomogram was created to assess the risk of PPF and validated by bootstrap resampling.

RESULTS

Among 112 participants with follow-up data, 22 (19.6%) met criteria for PPF between 12 and 24 months. An equal proportion of patients randomized to CYC (n = 11 of 56) and mycophenolate mofetil (n = 11 of 56) developed PPF. The baseline severity of ILD was similar for patients who did, compared to those who did not, experience PPF in terms of their baseline forced vital capacity percent predicted, diffusing capacity for carbon monoxide percent predicted, and quantitative radiological extent of ILD. Predictors in the nomogram included sex, baseline CXCL4 level, and baseline gastrointestinal reflux score. The nomogram demonstrated moderate discrimination in estimating the risk of PPF, with a C-index of 0.72 (95% confidence interval 0.60-0.84).

CONCLUSION

The SLS II data set provided a unique opportunity to investigate predictors of PPF and develop a nomogram to help clinicians identify patients with SSc-ILD who require closer monitoring while on therapy and potentially an alternative treatment approach. This nomogram warrants external validation in other SSc-ILD cohorts to confirm its predictive power.

Monocytes and macrophages: emerging mechanisms and novel therapeutic targets in pulmonary fibrosis

Pulmonary fibrosis results from a plethora of abnormal pathogenetic events. In idiopathic pulmonary fibrosis (IPF), inhalational, environmental, or occupational exposures in genetically and epigenetically predisposed individuals trigger recurrent cycles of alveolar epithelial cell injury, activation of coagulation pathways, chemoattraction, and differentiation of monocytes into monocyte-derived alveolar macrophages (Mo-AMs). When these events happen intermittently and repeatedly throughout the individual's life cycle, the wound repair process becomes aberrant leading to bronchiolization of distal air spaces, fibroblast accumulation, extracellular matrix deposition, and loss of the alveolar-capillary architecture. The role of immune dysregulation in IPF pathogenesis and progression has been underscored in the past mainly after the disappointing results of immunosuppressant use in IPF patients; however, recent reports highlighting the prognostic and mechanistic roles of monocytes and Mo-AMs revived the interest in immune dysregulation in IPF. In this review, we will discuss the role of these cells in the onset and progression of IPF, as well as potential targeted therapies.

Lung immune signatures define two groups of end-stage IPF patients

BACKGROUND

The role of the immune system in the pathobiology of Idiopathic Pulmonary Fibrosis (IPF) is controversial.

METHODS

To investigate it, we calculated immune signatures with Gene Set Variation Analysis (GSVA) and applied them to the lung transcriptome followed by unbiased cluster analysis of GSVA immune-enrichment scores, in 109 IPF patients from the Lung Tissue Research Consortium (LTRC). Results were validated experimentally using cell-based methods (flow cytometry) in lung tissue of IPF patients from the University of Pittsburgh (n = 26). Finally, differential gene expression and hypergeometric test were used to explore non-immune differences between clusters.

RESULTS

We identified two clusters (C#1 and C#2) of IPF patients of similar size in the LTRC dataset. C#1 included 58 patients (53%) with enrichment in GSVA immune signatures, particularly cytotoxic and memory T cells signatures, whereas C#2 included 51 patients (47%) with an overall lower expression of GSVA immune signatures (results were validated by flow cytometry with similar unbiased clustering generation). Differential gene expression between clusters identified differences in cilium, epithelial and secretory cell genes, all of them showing an inverse correlation with the immune response signatures. Notably, both clusters showed distinct features despite clinical similarities.

CONCLUSIONS

In end-stage IPF lung tissue, we identified two clusters of patients with very different levels of immune signatures and gene expression but with similar clinical characteristics. Weather these immune clusters differentiate diverse disease trajectories remains unexplored.

Peripheral Blood Single-Cell Sequencing Uncovers Common and Specific Immune Aberrations in Fibrotic Lung Diseases

Rationale and Objectives

The extent and commonality of peripheral blood immune aberrations in fibrotic interstitial lung diseases are not well characterized. In this study, we aimed to identify common and distinct immune aberrations in patients with idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (FHP) using cutting-edge single-cell profiling technologies.

Methods

Single-cell RNA sequencing was performed on patients and healthy controls' peripheral blood and bronchoalveolar lavage samples using 10X Genomics 5' gene expression and V(D)J profiling. Cell type composition, transcriptional profiles, cellular trajectories and signaling, and T and B cell receptor repertoires were studied. The standard Seurat R pipeline was followed for cell type composition and differential gene expression analyses. Transcription factor activity was imputed using the DoRothEA-VIPER algorithm. Pseudotime analyses were conducted using Monocle3, while RNA velocity analyses were performed with Velocyto, scVelo, and CellRank. Cell-cell connectomics were assessed using the Connectome R package. V(D)J analyses were conducted using CellRanger and Immcantation frameworks. Across all analyses, disease group differences were assessed using the Wilcoxon rank-sum test.

Measurements and Main Results

327,990 cells from 83 samples were profiled. Overall, changes in monocytes were common to IPF and FHP, whereas lymphocytes exhibited disease-specific aberrations. Both diseases displayed enrichment of CCL3 hi /CCL4 hi CD14+ monocytes (p<2.2e-16) and S100A hi CD14+ monocytes (p<2.2e-16) versus controls. Trajectory and RNA velocity analysis suggested that pro-fibrotic macrophages observed in BAL originated from peripheral blood monocytes. Lymphocytes exhibited disease-specific aberrations, with CD8+ GZMK hi T cells and activated B cells primarily enriched in FHP patients. V(D)J analyses revealed unique T and B cell receptor complementarity-determining region 3 (CDR3) amino acid compositions (p<0.05) in FHP and significant IgA enrichment in IPF (p<5.2e-7).

Conclusions

We identified common and disease-specific immune mechanisms in IPF and FHP; S100A hi monocytes and SPP1 hi macrophages are common to IPF and FHP, whereas GMZK hi T lymphocytes and T and B cell receptor repertoires were unique in FHP. Our findings open novel strategies for the diagnosis and treatment of IPF and FHP.

IL-6 trans-signaling in a humanized mouse model of scleroderma

Fibrosis is regulated by interactions between immune and mesenchymal cells. However, the capacity of cell types to modulate human fibrosis pathology is poorly understood due to lack of a fully humanized model system. MISTRG6 mice were engineered by homologous mouse/human gene replacement to develop an immune system like humans when engrafted with human hematopoietic stem cells (HSCs). We utilized MISTRG6 mice to model scleroderma by transplantation of healthy or scleroderma skin from a patient with pansclerotic morphea to humanized mice engrafted with unmatched allogeneic HSC. We identified that scleroderma skin grafts contained both skin and bone marrow-derived human CD4 and CD8 T cells along with human endothelial cells and pericytes. Unlike healthy skin, fibroblasts in scleroderma skin were depleted and replaced by mouse fibroblasts. Furthermore, HSC engraftment alleviated multiple signatures of fibrosis, including expression of collagen and interferon genes, and proliferation and activation of human T cells. Fibrosis improvement correlated with reduced markers of T cell activation and expression of human IL-6 by mesenchymal cells. Mechanistic studies supported a model whereby IL-6 trans-signaling driven by CD4 T cell-derived soluble IL-6 receptor complexed with fibroblast-derived IL-6 promoted excess extracellular matrix gene expression. Thus, MISTRG6 mice transplanted with scleroderma skin demonstrated multiple fibrotic responses centered around human IL-6 signaling, which was improved by the presence of healthy bone marrow-derived immune cells. Our results highlight the importance of IL-6 trans-signaling in pathogenesis of scleroderma and the ability of healthy bone marrow-derived immune cells to mitigate disease.

Precision medicine advances in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a highly heterogeneous, unpredictable and ultimately lethal chronic lung disease. Over the last decade, two anti-fibrotic agents have been shown to slow disease progression, however, both drugs are administered uniformly with minimal consideration of disease severity and inter-individual molecular, genetic, and genomic differences. Advances in biological understanding of disease endotyping and the emergence of precision medicine have shown that "a one-size-fits-all approach" to the management of chronic lung diseases is no longer appropriate. While precision medicine approaches have revolutionized the management of other diseases such as lung cancer and asthma, the implementation of precision medicine in IPF clinical practice remains an unmet need despite several reports demonstrating a large number of diagnostic, prognostic and theragnostic biomarker candidates in IPF. This review article aims to summarize our current knowledge of precision medicine in IPF and highlight barriers to translate these research findings into clinical practice.

Clinical significance of high monocyte counts for the continuous treatment with nintedanib

BACKGROUND

Nintedanib is now widely used to treat interstitial lung disease (ILD). Adverse events, which occur in not a few patients, make it difficult to continue nintedanib treatment, but the risk factors for adverse events are not well understood.

METHODS

In this retrospective cohort study, we enrolled 111 patients with ILDs treated with nintedanib and investigated the factors involved in starting dosage reduction, withdrawal, or discontinuation within 12 months, even with appropriate symptomatic treatment. We also examined the efficacy of nintedanib in reducing the frequency of acute exacerbations and the prevention of pulmonary function reduction.

RESULTS

Patients with high monocyte counts (> 0.454 × 109/L) had a significantly higher frequency of treatment failure, such as dosage reduction, withdrawal, or discontinuation. High monocyte count was as significant a risk factor as body surface area (BSA). Regarding efficacy, there was no difference in the frequency of acute exacerbations or the amount of decline in pulmonary function within 12 months between the normal (300 mg) and reduced (200 mg) starting dosage groups.

CONCLUSION

Our study results indicate that patients with higher monocyte counts (> 0.454 × 109/L) should very careful about side effects with regard to nintedanib administration. Like BSA, a higher monocyte count is considered a risk factor for nintedanib treatment failure. There was no difference in FVC decline and frequency of acute exacerbations between the starting doseage of nintedanib, 300 mg and 200 mg. Considering the risk of withdrawal periods and discontinuation, a reduced starting dosage may be acceptable in the patients with higher monocyte counts or small body sizes.

Targeting pathogenic macrophages by the application of SHP-1 agonists reduces inflammation and alleviates pulmonary fibrosis

Idiopathic pulmonary fibrosis is a progressive fibrotic disorder with no cure that is characterized by deterioration of lung function. Current FDA-approved drugs for IPF delay the decline in lung function, but neither reverse fibrosis nor significantly improve overall survival. SHP-1 deficiency results in hyperactive alveolar macrophages accumulating in the lung, which contribute to the induction of pulmonary fibrosis. Herein, we investigated whether employing a SHP-1 agonist ameliorates pulmonary fibrosis in a bleomycin-induced pulmonary fibrosis murine model. Histological examination and micro-computed tomography images showed that SHP-1 agonist treatment alleviates bleomycin-induced pulmonary fibrosis. Reduced alveolar hemorrhage, lung inflammation, and collagen deposition, as well as enhanced alveolar space, lung capacity, and improved overall survival were observed in mice administered the SHP-1 agonist. The percentage of macrophages collected from bronchoalveolar lavage fluid and circulating monocytes in bleomycin-instilled mice were also significantly reduced by SHP-1 agonist treatment, suggesting that the SHP-1 agonist may alleviate pulmonary fibrosis by targeting macrophages and reshaping the immunofibrotic niche. In human monocyte-derived macrophages, SHP-1 agonist treatment downregulated CSF1R expression and inactivated STAT3/NFκB signaling, culminating in inhibited macrophage survival and perturbed macrophage polarization. The expression of pro-fibrotic markers (e.g., MRC1, CD200R1, and FN1) by IL4/IL13-induced M2 macrophages that rely on CSF1R signaling for their fate-determination was restricted by SHP-1 agonist treatment. While M2-derived medium promoted the expression of fibroblast-to-myofibroblast transition markers (e.g., ACTA2 and COL3A1), the application of SHP-1 agonist reversed the transition in a dose-dependent manner. Our report indicates that pharmacological activation of SHP-1 ameliorates pulmonary fibrosis via suppression of CSF1R signaling in macrophages, reduction of pathogenic macrophages, and the inhibition of fibroblast-to-myofibroblast transition. Our study thus identifies SHP-1 as a druggable target for the treatment of IPF, and suggests that the SHP-1 agonist may be developed as an anti-pulmonary fibrosis medication that both suppresses inflammation and restrains fibroblast-to-myofibroblast transition.

Monocyte at diagnosis as a prognosis biomarker in tuberculosis patients with anemia

Background

Anemia leads to a lower cure rate and poor prognosis in tuberculosis patients. Effective predictors for the prognosis of tuberculosis with anemia (A-TB) are urgently needed. Monocyte has been proven to be a prognostic biomarker of many lung diseases. Whether monocyte that the predominant innate immune cell as early defense against tuberculosis can predict A-TB is not known.

Methods

Data for A-TB patients with initial treatment in Shanghai Pulmonary Hospital were retrospectively collected and analyzed. Logistics regression analysis was used to study the correlation between peripheral blood cells and treatment outcomes. The receiver operating characteristic (ROC) curve was used to determine the cut-off value. We estimated a 12-month prognosis using Kaplan-Meier techniques. The Cox proportional hazards model was used for the univariate and multivariate analyses to analyze the predictors of poor prognosis of A-TB.

Results

Of 181 patients analyzed, 94 were cured and 87 non-cured. Logistic regression analysis identified monocyte as an independent immune-related risk factor for the prognosis of A-TB (OR: 7.881, 95% CI: 1.675-37.075, P = 0.009). The ROC curve analysis proved that the most discriminative cut-off value of monocyte was 0.535 × 10^9/L. K-M analysis demonstrated that the cumulative cure rates of A-TB were significantly higher in A-TB with monocyte < 0.535 × 10^9/L (69.62%) than that in those with monocyte ≥ 0.535 × 10^9/L (38.24%) (Log-rank, χ² = 16.530, P < 0.0001). On univariate and multivariable analysis, monocyte was an independent predictor of poor prognosis in A-TB. Similarly, monocyte was also an independent predictor of poor pulmonary cavity closure in A-TB (HR: 3.614, 95% CI: 1.335-9.787, P = 0.011).

Conclusion

In A-TB patients, elevated monocyte was associated with poor prognosis and poor cavity pulmonary closure. Monocyte may provide a simple and inexpensive prognostic biomarker in A-TB.

Single-cell profiling reveals immune aberrations in progressive idiopathic pulmonary fibrosis

Rationale

Changes in peripheral blood cell populations have been observed but not detailed at single-cell resolution in idiopathic pulmonary fibrosis (IPF).

Objectives

To provide an atlas of the changes in the peripheral immune system in stable and progressive IPF.

Methods

Peripheral blood mononuclear cells (PBMCs) from IPF patients and controls were profiled using 10x Chromium 5' single-cell RNA sequencing (scRNA-seq). Flow cytometry was used for validation. Protein concentrations of Regulatory T-cells (Tregs) and Monocytes chemoattractants were measured in plasma and lung homogenates from patients and controls.

Measurements and Main Results

Thirty-eight PBMC samples from 25 patients with IPF and 13 matched controls yielded 149,564 cells that segregated into 23 subpopulations, corresponding to all expected peripheral blood cell populations. Classical monocytes were increased in progressive and stable IPF compared to controls (32.1%, 25.2%, 17.9%, respectively, p<0.05). Total lymphocytes were decreased in IPF vs controls, and in progressive vs stable IPF (52.6% vs 62.6%, p=0.035). Tregs were increased in progressive IPF (1.8% vs 1.1%, p=0.007), and were associated with decreased survival (P=0.009 in Kaplan-Meier analysis). Flow cytometry analysis confirmed this finding in an independent cohort of IPF patients. Tregs were also increased in two cohorts of lung scRNA-seq. CCL22 and CCL18, ligands for CCR4 and CCR8 Treg chemotaxis receptors, were increased in IPF.

Conclusions

The single-cell atlas of the peripheral immune system in IPF, reveals an outcome-predictive increase in classical monocytes and Tregs, as well as evidence for a lung-blood immune recruitment axis involving CCL7 (for classical monocytes) and CCL18/CCL22 (for Tregs).

Elevated circulating monocytes and monocyte activation in COVID-19 convalescent individuals

Background

Monocytes and macrophages play a pivotal role in inflammation during acute SARS-CoV-2 infection. However, their contribution to the development of post-acute sequelae of SARS-CoV-2 infection (PASC) are not fully elucidated.

Methods

A cross-sectional study was conducted comparing plasma cytokine and monocyte levels among three groups: participants with pulmonary PASC (PPASC) with a reduced predicted diffusing capacity for carbon monoxide [DLCOc, <80%; (PG)]; fully recovered from SARS-CoV-2 with no residual symptoms (recovered group, RG); and negative for SARS-CoV-2 (negative group, NG). The expressions of cytokines were measured in plasma of study cohort by Luminex assay. The percentages and numbers of monocyte subsets (classical, intermediate, and non-classical monocytes) and monocyte activation (defined by CD169 expression) were analyzed using flow cytometry analysis of peripheral blood mononuclear cells.

Results

Plasma IL-1Ra levels were elevated but FGF levels were reduced in PG compared to NG. Circulating monocytes and three subsets were significantly higher in PG and RG compared to NG. PG and RG exhibited higher levels of CD169+ monocyte counts and higher CD169 expression was detected in intermediate and non-classical monocytes from RG and PG than that found in NG. Further correlation analysis with CD169+ monocyte subsets revealed that CD169+ intermediate monocytes negatively correlated with DLCOc%, and CD169+ non-classical monocytes positively correlated with IL-1α, IL-1β, MIP-1α, Eotaxin, and IFN-γ.

Conclusion

This study present evidence that COVID convalescents exhibit monocyte alteration beyond the acute COVID-19 infection period even in convalescents with no residual symptoms. Further, the results suggest that monocyte alteration and increased activated monocyte subsets may impact pulmonary function in COVID-19 convalescents. This observation will aid in understanding the immunopathologic feature of pulmonary PASC development, resolution, and subsequent therapeutic interventions.

Cigarette Smoking, and Blood Monocyte Count Correlate with Chronic Lung Injuries and Mortality

Background

Cigarette smoking (CS)-related monocytosis contributes to the development of chronic lung injuries via complex mechanisms. We aim to determine correlations between measures of CS and monocytes, their capacities to predict chronic lung diseases, and their associations with mortality.

Methods

A single-center retrospective study of patients undergoing surgical resection for suspected lung nodules/masses was performed. CS was quantified as cigarettes smoked per day (CPD), duration of smoking, composite pack years (CPY), current smoking status, and smoking cessation years. A multivariate logistic regression analysis was performed.

Results

Of 382 eligible patients, 88% were ever smokers. In this group, 45% were current smokers with mean CPD of 27.2±40.0. CPY and duration of smoking showed positive linear correlations with percentage monocyte count. Physiologically, CPY was associated with progressive obstruction, hyperinflation, and reduced diffusion capacity (DL_CO). Across the quartiles of smoking, there was an accumulation of radiologic and histologic abnormalities. Anthracosis and emphysema were associated with CPD, while lung cancer, respiratory bronchiolitis (RB), emphysema, and honeycombing were statistically related to duration of smoking. Analysis using consecutive CPY showed associations with lung cancer (≥10 and <30), fibrosis (≥20 and <40), RB (≥50), anthracosis and emphysema (≥10 and onwards). Percentage monocytes correlated with organizing pneumonia (OP), fibrosis, and emphysema. The greater CPY increased mortality across the groups. Significant predictors of mortality included percentage monocyte, anemia, GERD, and reduced DL_CO.

Conclusion

Indices of CS and greater monocyte numbers were associated with endpoints of chronic lung disease suggesting a participation in pathogenesis. Application of these easily available metrics may support a chronology of CS-induced chronic lung injuries. While a relative lesser amount of smoking can be associated with lung cancer and fibrosis, greater CPY increases the risk for emphysema. Monocytosis predicted lung fibrosis and mortality. Duration of smoking may serve as a better marker of monocytosis and associated chronic lung diseases.

Classical monocyte-derived macrophages as therapeutic targets of umbilical cord mesenchymal stem cells: comparison of intratracheal and intravenous administration in a mouse model of pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease that has no cure. Although mesenchymal stem cells (MSCs) have been reported to ameliorate lung inflammation and fibrosis in mouse models, their mechanisms of action remain unknown. Therefore, we aimed to determine the changes in various immune cells, especially macrophages and monocytes, involved in the effects of MSC treatment on pulmonary fibrosis.

METHODS

We collected and analyzed explanted lung tissues and blood from patients with IPF who underwent lung transplantation. After establishing a pulmonary fibrosis model via the intratracheal administration of bleomycin (BLM) to 8-week-old mice, MSCs derived from human umbilical cords were administered intravenously or intratracheally on day 10 and the lungs were immunologically analyzed on days 14 and 21. Flow cytometry was performed to analyze the immune cell characteristics, and gene expression levels were examined using quantitative reverse transcription-polymerase chain reaction.

RESULTS

In the histological analysis of explanted human lung tissues, the terminally fibrotic areas contained a larger number of macrophages and monocytes than the early fibrotic areas of the lungs. When human monocyte-derived macrophages (MoMs) were stimulated with interleukin-13 in vitro, the expression of type 2 macrophage (M2) markers was more prominent in MoMs from the classical monocyte subset than in those from intermediate or non-classical monocyte subsets, and MSCs suppressed M2 marker expression independent of MoM subsets. In the mouse model, the increased number of inflammatory cells in the bronchoalveolar lavage fluid and the degree of lung fibrosis observed in BLM-treated mice were significantly reduced by MSC treatment, which tended to be more prominent with intravenous administration than intratracheal administration. Both M1 and M2 MoMs were upregulated in BLM-treated mice. The M2c subset of M2 MoMs was significantly reduced by MSC treatment. Among M2 MoMs, M2 MoMs derived from Ly6C⁺ monocytes were most effectively regulated by the intravenous administration, not intratracheal administration, of MSCs.

CONCLUSIONS

Inflammatory classical monocytes may play a role in lung fibrosis in human IPF and BLM-induced pulmonary fibrosis. Intravenous rather than intratracheal administration of MSCs may ameliorate pulmonary fibrosis by inhibiting monocyte differentiation into M2 macrophages.

Correlation of monocyte counts with clinical outcomes in idiopathic nonspecific interstitial pneumonia

Higher blood monocyte counts are related to worse survival in idiopathic pulmonary fibrosis. However, studies evaluating the association between blood monocyte counts and clinical outcomes of idiopathic nonspecific interstitial pneumonia (iNSIP) are lacking. We evaluated the impact of monocyte counts on iNSIP prognosis. iNSIP patients (n = 126; median age, 60 years; female, n = 64 [50.8%]) diagnosed by surgical lung biopsy were enrolled and categorized into low (monocyte < 600/µL) and high (monocyte ≥ 600/µL) monocyte groups. The median follow-up duration was 53.0 months. After adjusting for age, sex, and smoking history, the annual decline in forced vital capacity (FVC) showed differences between the monocyte groups (P_interaction = 0.006) (low vs. high; - 28.49 mL/year vs. - 65.76 mL/year). The high-monocyte group showed a worse survival rate (P = 0.01) compared to low monocyte group. The 5-year survival rates were 83% and 72% in the low- and high-monocyte groups, respectively. In the Cox-proportional hazard analysis, older age, male sex, low baseline FVC, and diffusing capacity of the lung for carbon monoxide were independent risk factors for mortality. However, monocyte count (Hazard ratio 1.61, P = 0.126) was not an independent prognostic factor. Although high monocyte count might be associated with faster lung function decline, it could not independently predict survival in iNSIP.

Mass cytometry identifies characteristic immune cell subsets in bronchoalveolar lavage fluid from interstitial lung diseases

Immune cells have been implicated in interstitial lung diseases (ILDs), although their phenotypes and effector mechanisms remain poorly understood. To better understand these cells, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid (BALF) from patients with idiopathic pulmonary fibrosis (IPF), connective-tissue disease (CTD)-related ILD, and sarcoidosis, using two panels including 64 markers. Among myeloid cells, we observed the expansion of CD14⁺ CD36^hi CD84^hiCCR2^- monocyte populations in IPF. These CD14⁺ CD36^hi CD84^hi CCR2^- subsets were also increased in ILDs with a progressive phenotype, particularly in a case of acute exacerbation (AEx) of IPF. Analysis of B cells revealed the presence of cells at various stages of differentiation in BALF, with a higher percentage of IgG memory B cells in CTD-ILDs and a trend toward more FCRL5⁺ B cells. These FCRL5⁺ B cells were also present in the patient with AEx-IPF and sarcoidosis with advanced lung lesions. Among T cells, we found increased levels of IL-2R⁺ TIGIT⁺ LAG3⁺ CD4⁺ T cells in IPF, increased levels of CXCR3⁺ CD226⁺ CD4⁺ T cells in sarcoidosis, and increased levels of PD1⁺ TIGIT⁺ CD57⁺ CD8⁺ T cells in CTD-ILDs. Together, these findings underscore the diverse immunopathogenesis of ILDs.

Multi-center evaluation of baseline neutrophil-to-lymphocyte (NLR) ratio as an independent predictor of mortality and clinical risk stratifier in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal disorder with a variable disease trajectory. The aim of this study was to assess the potential of neutrophil-to-lymphocyte ratio (NLR) to predict outcomes in IPF.

Methods

We adopted a two-stage discovery (n = 71) and validation (n = 134) design using patients from the UCL partners (UCLp) cohort. We then combined discovery and validation cohorts and included an additional 794 people with IPF, using real-life data from 5 other UK centers, to give a combined cohort of 999 patients. Data were collected from patients presenting over a 13-year period (2006-2019) with mean follow up of 3.7 years (censoring: 2018-2020).

Findings

In the discovery analysis, we showed that high values of NLR (>/ = 2.9 vs < 2.9) were associated with increased risk of mortality in IPF (HR 2.04, 95% CI 1.09-3.81, n = 71, p = 0.025). This was confirmed in the validation (HR 1.91, 95% CI 1.15-3.18, n = 134, p = 0.0114) and combined cohorts (HR 1.65, n = 999, 95% CI 1.39-1.95; p < 0·0001). NLR correlated with GAP stage and GAP index (p < 0.0001). Stratifying patients by NLR category (low/high) showed significant differences in survival for GAP stage 2 (p < 0.0001), however not for GAP stage 1 or 3. In a multivariate analysis, a high NLR was an independent predictor of mortality/progression after adjustment for individual GAP components and steroid/anti-fibrotic use (p < 0·03). Furthermore, incorporation of baseline NLR in a modified GAP-stage/index, GAP-index/stage-plus, refined prognostic ability as measured by concordance (C)-index.

Interpretation

We have identified NLR as a widely available test that significantly correlates with lung function, can predict outcomes in IPF and refines cohort staging with GAP. NLR may allow timely prioritisation of at-risk patients, even in the absence of lung function.

Funding

Breathing Matters, GSK, CF Trust, BLF-Asthma, MRC, NIHR Alpha-1 Foundation.

Circulating CTRP9 Is Associated With Severity of Systemic Sclerosis-Associated Interstitial Lung Disease

OBJECTIVE

While interstitial lung disease (ILD) is the leading cause of morbidity and mortality in systemic sclerosis (SSc), there remains a paucity of predictive markers to assess disease progression. We previously demonstrated that adipose tissue metabolism and adipokine homeostasis is dysregulated in SSc. The present study was undertaken to determine the association and predictive ability of the novel adipokine C1q/tumor necrosis factor-related protein 9 (CTRP9) for SSc-associated ILD.

METHODS

We performed a retrospective longitudinal study utilizing the Northwestern Scleroderma Program Patient Registry and Biorepository. Serum levels of CTRP9 were measured in 110 SSc patients at baseline, and demographic, clinical, and pulmonary function test data were collected in 12-month intervals to 48 months. Longitudinal trajectory of forced vital capacity percent predicted (FVC%) was used as a primary outcome measure. We utilized a mixed model to compare trajectories of lung function by CTRP9 groups and performed latent trajectory analysis to accommodate for heterogeneity.

RESULTS

In cross-sectional analysis, elevated circulating CTRP9 was associated with significantly lower FVC% at baseline (72% ± 17 versus 80% ± 18; P = 0.02) and 48 months (68 ± 19 versus 84 ± 18; P = 0.001). In mixed model analysis, high CTRP9 was associated with worse lung function but not with a different trajectory (P = 0.23). In contrast, low CTRP9 identified patients with stability of lung disease with reasonable accuracy (sensitivity 73%). Latent trajectory analysis confirmed the association of lower CTRP9 with higher FVC%.

CONCLUSION

Higher circulating CTRP9 associated with worse pulmonary function, while low CTRP9 identified patients with lung disease stability over time. These findings suggest that CTRP9 may be a potential biomarker in SSc-associated ILD.

Hotspots and Frontiers of Host Immune Response in Idiopathic Pulmonary Fibrosis: A Bibliometric and Scientific Visual Research from 2000 to 2022

Background

Idiopathic pulmonary fibrosis (IPF) is a disease with significant morbidity, progressive deterioration of lung function till death, and lack of effective treatment options. This study aims to explore the global research trends in IPF and immune response to predict the research hotspot in the future. Materials and methods. All related publications on IPF and immune response since the establishment of diagnostic criteria for IPF were retrieved using the Web of Science (WOS) database. VOSviewer, GraphPad Prism 6, CiteSpace version 5.6. R5 64-bit, and a bibliometrics online platform were used to extract and analyze the trends in relevant fields.

Results

From March 1, 2000, to September 30, 2022, a total of 658 articles with 25,126 citations met the inclusion criteria. The United States ranked first in number of publications (n = 217), number of citations (n = 14,745), and H-index (62). China ranked second in publications (n = 124) and seventh and fifth for citation frequency and H-index, respectively. The American Journal of Respiratory and Critical Care Medicine (impact factor = 30.528) published the most articles in the field. The author Kaminski N. from the United States was the most influential author with 26 publications and an H-index of 24. Among the 52 keywords that co-occurred at least 20 times, the main keywords were concentrated in "Inflammation related" and "Biomarker related" clusters. "biomarker" (AAY 2018.64, 25 times) was a newly emerged keyword.

Conclusions

The United States has an unequivocal advantage in IPF and immunization, but China shows a faster developing trend. The American Journal of Respiratory and Critical Care Medicine should be prioritized for leading articles. This study indicates that exploration of ideal immune-related biomarkers to provide evidence for the clinical work of IPF might be a hotspot in the near future.

Protocol for Classification Single-Cell PBMC Types from Pathological Samples Using Supervised Machine Learning

Peripheral blood mononuclear cells (PBMC) are mixed subpopulations of blood cells composed of five cell types. PBMC are widely used in the study of the immune system, infectious diseases, cancer, and vaccine development. Single-cell transcriptomics (SCT) allows the labeling of cell types by gene expression patterns from biological samples. Classifying cells into cell types and states is essential for single-cell analyses, especially in the classification of diseases and the assessment of therapeutic interventions, and for many secondary analyses. Most of the classification of cell types from SCT data use unsupervised clustering or a combination of unsupervised and supervised methods including manual correction. In this chapter, we describe a protocol that uses supervised machine learning (ML) methods with SCT data for the classification of PBMC cell types in samples representing pathological states. This protocol has three parts: (1) data preprocessing, (2) labeling of reference PBMC SCT datasets and training supervised ML models, and (3) labeling new PBMC datasets from disease samples. This protocol enables building classification models that are of high accuracy and efficiency. Our example focuses on 10× Genomics technology but applies to datasets from other SCT platforms.

Immune mechanisms in fibrotic pulmonary sarcoidosis

Sarcoidosis is an immune-mediated disorder. Its immunopathology has been steadily mapped out over the past few decades. Despite this, the underpinning mechanisms for progressive fibrotic sarcoidosis is an almost uncharted area. Consequently, there has been little change in the clinical management of fibrotic sarcoidosis over the decades and an unfocused search for new therapeutics. In this review, we provide a comprehensive examination of the relevant immune findings in fibrotic and/or progressive pulmonary sarcoidosis and propose a unifying mechanism for the pathobiology of fibrosis in sarcoidosis.

Research progress of single-cell transcriptome sequencing in autoimmune diseases and autoinflammatory disease: A review

Autoimmunity refers to the phenomenon that the body's immune system produces antibodies or sensitized lymphocytes to its own tissues to cause an immune response. Immune disorders caused by autoimmunity can mediate autoimmune diseases. Autoimmune diseases have complicated pathogenesis due to the many types of cells involved, and the mechanism is still unclear. The emergence of single-cell research technology can solve the problem that ordinary transcriptome technology cannot be accurate to cell type. It provides unbiased results through independent analysis of cells in tissues and provides more mRNA information for identifying cell subpopulations, which provides a novel approach to study disruption of immune tolerance and disturbance of pro-inflammatory pathways on a cellular basis. It may fundamentally change the understanding of molecular pathways in the pathogenesis of autoimmune diseases and develop targeted drugs. Single-cell transcriptome sequencing (scRNA-seq) has been widely applied in autoimmune diseases, which provides a powerful tool for demonstrating the cellular heterogeneity of tissues involved in various immune inflammations, identifying pathogenic cell populations, and revealing the mechanism of disease occurrence and development. This review describes the principles of scRNA-seq, introduces common sequencing platforms and practical procedures, and focuses on the progress of scRNA-seq in 41 autoimmune diseases, which include 9 systemic autoimmune diseases and autoinflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.) and 32 organ-specific autoimmune diseases (5 Skin diseases, 3 Nervous system diseases, 4 Eye diseases, 2 Respiratory system diseases, 2 Circulatory system diseases, 6 Liver, Gallbladder and Pancreas diseases, 2 Gastrointestinal system diseases, 3 Muscle, Bones and joint diseases, 3 Urinary system diseases, 2 Reproductive system diseases). This review also prospects the molecular mechanism targets of autoimmune diseases from the multi-molecular level and multi-dimensional analysis combined with single-cell multi-omics sequencing technology (such as scRNA-seq, Single cell ATAC-seq and single cell immune group library sequencing), which provides a reference for further exploring the pathogenesis and marker screening of autoimmune diseases and autoimmune inflammatory diseases in the future.

Myeloid- and Epithelial-derived Heparin-Binding Epidermal Growth Factor-like Growth Factor Promotes Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a poorly understood, progressive lethal lung disease with no known cure. In addition to alveolar epithelial cell (AEC) injury and excessive deposition of extracellular matrix proteins, chronic inflammation is a hallmark of IPF. Literature suggests that the persistent inflammation seen in IPF primarily consists of monocytes and macrophages. Recent work demonstrates that monocyte-derived alveolar macrophages (moAMs) drive lung fibrosis, but further characterization of critical moAM cell attributes is necessary. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is an important epidermal growth factor receptor ligand that has essential roles in angiogenesis, wound healing, keratinocyte migration, and epithelial-mesenchymal transition. Our past work has shown HB-EGF is a primary marker of profibrotic M2 macrophages, and this study seeks to characterize myeloid-derived HB-EGF and its primary mechanism of action in bleomycin-induced lung fibrosis using Hbegff/f;Lyz2Cre+ mice. Here, we show that patients with IPF and mice with pulmonary fibrosis have increased expression of HB-EGF and that lung macrophages and transitional AECs of mice with pulmonary fibrosis and humans all express HB-EGF. We also show that Hbegff/f;Lyz2Cre+ mice are protected from bleomycin-induced fibrosis and that this protection is likely multifactorial, caused by decreased CCL2-dependent monocyte migration, decreased fibroblast migration, and decreased contribution of HB-EGF from AEC sources when HB-EGF is removed under the Lyz2Cre promoter.

Effect of M6A regulators on diagnosis, subtype classification, prognosis and novel therapeutic target development of idiopathic pulmonary fibrosis

Molecular biology studies show that RNA N6-methyladenosine (m6A) modifications may take part in the incidence and development of idiopathic pulmonary fibrosis (IPF). Nonetheless, the roles of m6A regulators in IPF are not fully demonstrated. In this study, 12 significant m6A regulators were filtered out between healthy controls and IPF patients using GSE33566 dataset. Random forest algorithm was used to identify 11 candidate m6A regulators to predict the incidence of IPF. The 11 candidate m6A regulators included leucine-rich PPR motif-containing protein (LRPPRC), methyltransferase-like protein 3, FTO alpha-ketoglutarate dependent dioxygenase (FTO), methyltransferase-like 14/16, zinc finger CCCH domain-containing protein 13, protein virilizer homolog, Cbl proto-oncogene like 1, fragile X messenger ribonucleoprotein 1 and YTH domain containing 1/2. A nomogram model was constructed based on 11 candidate m6A regulators and considered beneficial to IPF patients using decision curve analysis. Consensus clustering method was used to distinctly divide IPF patients into two m6A patterns (clusterA and clusterB) based on 12 significant m6A regulators. M6A scores of all IPF patients were obtained using principal component analysis to quantify the m6A patterns. Patients in clusterB had higher m6A scores than those in clusterA. Furthermore, patients in clusterB were correlated with Th17 and Treg cell infiltration, innate immunity and Th1 immunity, while those in clusterA were correlated with adaptive immunity and Th2 immunity. Patients in clusterB also had higher expressions of mesenchymal markers and regulatory factors of fibrosis but lower expressions of epithelial markers. Lastly and interestingly, two m6A regulators, LRPPRC (p = 0.011) and FTO (p = 0.042), were identified as novel prognostic genes in IPF patients for the first time using an external GSE93606 dataset. Both of them had a positive correlation with a better prognosis and may serve as therapy targets. Thus, we conducted virtual screening to discover potential drugs targeting LRPPRC and FTO in the treatment of IPF. In conclusion, m6A regulators are crucial to the onset, development and prognosis of IPF. Our study on m6A patterns may provide clues for clinical diagnosis, prognosis and targeted therapeutic drugs development for IPF.

Identification of diagnostic gene biomarkers related to immune infiltration in patients with idiopathic pulmonary fibrosis based on bioinformatics strategies

Objective

The study aims to identify potential diagnostic markers of idiopathic pulmonary fibrosis (IPF) and analyze the significance of immune cell infiltration in this pathology.

Materials and methods

Download two publicly available gene expression profiles (GSE10667 and GSE24206 datasets) from the GEO database including 48 Idiopathic pulmonary fibrosis (IPF) samples and 21 human control samples and select for distinctly expressed genes (DEG) from them. Lasso regression model and support vector machine recursive feature elimination S,V,R,F analysis were used to check candidate biomarkers. The area under the subject's work characteristic curve (AUC) value is used to evaluate its recognition ability. The GSE53845 dataset (40 IPF patients and 8 controls) continue to validate the expression level and diagnostic value of biomarkers in IPF. Comprehensive analysis of immune infiltrated cells of IPF was performed using R software and immune cell infiltration estimation analysis tool- deconvolution algorithm (CIBERSORT).

Results

43 DEGs were identified in total. The identified DEGs mostly involve pneumonia, lung disease, collagen disease, obstructive pulmonary disease and other diseases. The activation of IL-17 signaling pathways, amoebic disease, interaction of viral proteins with cytokines and cytokine receptors, protein digestion and absorption, and flaccid hormone signaling pathways in IPF were different from the control group. The expression degree of CRTAC1, COL10A1, COMP, RPS4Y1, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 in IPF tissue were prominently higher than the normal group. Immune cell infiltration analysis showed that CRTAC1, COL10A1, COMP, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 were associated with monocytes, plasma cells, neutrophils, and regulatory (treg) T cells.

Conclusion

CRTAC1, COL10A1, COMP, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 can be used as diagnostic markers for IPF, providing new ideas for the future study of IPF occurrence and molecular mechanisms.

Clinical, imaging, and blood biomarkers to assess 1-year progression risk in fibrotic interstitial lung diseases-Development and validation of the honeycombing, traction bronchiectasis, and monocyte (HTM)-score

INTRODUCTION

Progression of fibrotic interstitial lung disease (ILD) leads to irreversible loss of lung function and increased mortality. Based on an institutional ILD registry, we aimed to evaluate biomarkers derived from baseline patient characteristics, computed tomography (CT), and peripheral blood for prognosis of disease progression in fibrotic ILD patients.

METHODS

Of 209 subsequent ILD-board patients enregistered, 142 had complete follow-up information and were classified fibrotic ILD as defined by presence of reticulation or honeycombing using a standardized semi-quantitative CT evaluation, adding up typical ILD findings in 0-6 defined lung fields. Progression at 1 year was defined as relative loss of ≥10% in forced vital capacity, of ≥15% in diffusion capacity for carbon monoxide, death, or lung transplant. Two-thirds of the patients were randomly assigned to a derivation cohort evaluated for the impact of age, sex, baseline lung function, CT finding scores, and blood biomarkers on disease progression. Significant variables were included into a regression model, its results were used to derive a progression-risk score which was then applied to the validation cohort.

RESULTS

In the derivation cohort, age, monocyte count ≥0.65 G/L, honeycombing and traction bronchiectasis extent had significant impact. Multivariate analyses revealed the variables monocyte count ≥0.65 G/L (1 point) and combined honeycombing or traction bronchiectasis score [0 vs. 1-4 (1 point) vs. 5-6 lung fields (2 points)] as significant, so these were used for score development. In the derivation cohort, resulting scores of 0, 1, 2, and 3 accounted for 1-year progression rates of 20, 25, 46.9, and 88.9%, respectively. Similarly, in the validation cohort, progression at 1 year occurred in 0, 23.8, 53.9, and 62.5%, respectively. A score ≥2 showed 70.6% sensitivity and 67.9% specificity, receiver operating characteristic analysis for the scoring model had an area under the curve of 71.7%.

CONCLUSION

The extent of honeycombing and traction bronchiectasis, as well as elevated blood monocyte count predicted progression within 1 year in fibrotic ILD patients.

The Role of Serum 1,25-Dihydroxy Vitamin D3 and PCT in Idiopathic Pulmonary Fibrosis

OBJECTIVE

Biomarkers for the acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) are urgently needed to provide better patient management. We aimed to investigate whether serum 1,25(OH)2D3 (1,25-dihydroxy vitamin D3) levels predict AE-IPF and whether they could be a potential prognostic biomarker for IPF.

PARTICIPANTS AND METHODS

This prospective study included 72 patients with IPF (31 with stable IPF and 41 with AE-IPF). All participants were recruited during hospitalisation at Tianjin Chest Hospital and were followed up for at least 12 months. Demographics, comorbidities, arterial blood gas, and serum biochemical profile, radiological features, and anti-fibrotic therapy were evaluated. Serum concentrations of 1,25(OH)2D3 and transforming growth factor beta1 (TGFβ1) were detected using enzyme-linked immunosorbent assay (ELISA). Risk factors for AE-IPF were identified using multivariate analysis. Prognostic factors were assessed using Kaplan-Meier and Cox regression analyses.

RESULTS

Baseline values of alveolar-arterial oxygen difference (A-aDO2) (40.85 mmHg vs 29.2 mmHg, p =0.035), white blood cell counts (10.09 ± 4.2×109/L vs 7.46 ± 7.84×109/L, p <0.001), percentage of monocytes (7.36 ± 1.36% vs 6.6 ± 1.2%, p =0.017), C-reactive protein (CRP) (2.1 mg/dL vs 1.12 mg/dL, p =0.015) and procalcitonin (PCT) (36.59% vs 3.23%, p <0.001) were significantly higher in AE-IPF patients than in stable IPF patients. Instead, the mean concentration of serum calcium and 1,25(OH)2D3 at baseline were higher in IPF patients with stable disease than in those with acute exacerbation (2.17 ± 0.13 nmol/L vs 2.09 ± 0.13 nmol/L, p =0.023 and 16.62 pg/mL vs 11.58 pg/mL, p <0.001, respectively). In multivariate analysis, a higher proportion of patients with lower serum 1,25(OH)2D3 levels experienced AE-IPF (OR 0.884, 95% CI 0.791-0.987, p =0.029), and rising serum PCT level (PCT > 0.05 ng/mL) was associated with an increased risk of mortality (HR 3.664, 95% CI 1.010-12.900, p =0.043).

CONCLUSION

Decreased serum 1,25(OH)2D3 is associated with an increased risk of acute exacerbation for patients with IPF. A high serum PCT level is predictive of worse prognosis in IPF patients. 1,25(OH)2D3 may be a potential biomarker for AE-IPF, while PCT could be a prognostic biomarker for IPF.

Blood monocyte counts as a prognostic biomarker and predictor in Chinese patients with idiopathic pulmonary fibrosis

OBJECTIVES

We sought to evaluate the prognostic value of blood routine parameters and biochemical parameters, especially inflammation-related biomarkers, and establish an inflammation-related prognostic model in Chinese patients with idiopathic pulmonary fibrosis (IPF).

MATERIAL/METHODS

Patients diagnosed as IPF at Beijing Chaoyang Hospital and aged 40 years and older were consecutively enrolled from June 2000 to March 2015, and finally, a total of 377 patients were enrolled in the derivation cohort. The follow-up ended in December 2016. We used Cox proportional hazard model to calculate the hazard ratio (HR) and establish the prognostic model. The discrimination and calibration of the prognostic model were evaluated in an independent validation cohort enrolled from China-Japan Friendship Hospital between January 2015 and December 2019.

RESULTS

Multivariate analysis revealed that patients with elevated monocyte-to-red blood cell count ratio (MRR) and monocyte counts showed increased risk of mortality. The clinical-physiological-biomarker (CPB) index and CPB stage we established in this study were a significant predictor, and the C-index for CPB index and CPB stage in the validation cohort was 0.635 (95% CI: 0.558-0.712) and 0.619 (95% CI: 0.544-0.694), respectively. Patients in CPB stage III had the poorest survival.

CONCLUSION

We developed and validated a new inflammation-related prognostic model (CPB index and CPB stage) which was integration of age, gender, FVC (%, predicted), DLCO (%, predicted), Charlson Comorbidity Index, and blood monocyte counts. This prediction model exhibited strong ability in predicting mortality in Chinese patients with IPF.

Hematopoietic Stem Cells in Wound Healing Response

Significance: Emerging evidence has shown a link between the status of hematopoietic stem cells (HSCs) and wound healing responses. Thus, better understanding HSCs will contribute to further advances in wound healing research. Recent Advances: Myeloid cells such as neutrophils and monocyte-derived macrophages are critical players in the process of wound healing. HSCs actively respond to wound injury and other tissue insults, including infection and produce the effector myeloid cells, and a failing of the HSC response can result in impaired wound healing. Technological advances such as transcriptome at single-cell resolution, epigenetics, three-dimensional imaging, transgenic animals, and animal models, have provided novel concepts of myeloid generation (myelopoiesis) from HSCs, and have revealed cell-intrinsic and -extrinsic mechanisms that can impact HSC functions in the context of health conditions. Critical Issues: The newer concepts include-the programmed cellular fate at a differentiation stage that is used to be considered as the multilineage, the signaling pathways that can activate HSCs directly and indirectly, the mechanisms that can deteriorate HSCs, the roles and remodeling of the surrounding environment for HSCs and their progenitors (the niche). Future Directions: The researches on HSCs, which produce blood cells, should contribute to the development of blood biomarkers predicting a risk of chronic wounds, which may transform clinical practice of wound care with precision medicine for patients at high risk of poor healing.