Cell profiles of bronchoalveolar lavage fluid as prognosticators of idiopathic pulmonary fibrosis/usual interstitial pneumonia among Japanese Patients

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.

S100 Calcium-Binding Protein A9, a Potential Novel Diagnostic Biomarker for Idiopathic Pulmonary Fibrosis

BACKGROUND

Neutrophilic inflammation is a characteristic feature of idiopathic pulmonary fibrosis (IPF). S100 calcium-binding protein A9 (S100A9) is a neutrophil-derived protein involved in the development of neutrophil-related chronic inflammatory disorders. However, the role of S100A9 in IPF remains unclear.

METHODS

We used enzyme-linked immunosorbent assays to measure S100A9 levels in bronchoalveolar lavage fluid (BALF) and serum obtained from healthy controls (HCs) and patients with IPF, non-specific interstitial pneumonia, hypersensitivity pneumonitis, and sarcoidosis.

RESULTS

Compared with HCs, BALF S100A9 levels were significantly higher in IPF patients (P < 0.001), patients with hypersensitivity pneumonitis (P = 0.043), and patients with nonspecific interstitial pneumonia (P < 0.001). The S100A9 level in BALF of 0.093 ng/mL could distinguish IPF patients from HCs, with a specificity of 78.8% and a sensitivity of 81.6%. Similarly, the S100A9 level in BALF of 0.239 ng/mL had a specificity of 64.7% and a sensitivity of 66.7% for distinguishing IPF patients from patients with other interstitial lung diseases. Additionally, BALF S100A9 levels were significantly correlated with neutrophil counts (r = 0.356, P < 0.001) in BALF. IPF patients with S100A9 levels in BALF > 0.533 ng/mL had lower survival rates, compared with patients who had levels ≤ 0.553 ng/mL (n = 49; hazard ratio [HR], 3.62; P = 0.021). Combination analysis revealed that IPF patients with S100A9 levels in BALF> 0.553 ng/mL or neutrophil percentages > 49.1% (n = 43) had significantly lower survival rates than patients with S100A9 levels in BALF ≤ 0.553 ng/mL and neutrophil percentages ≤ 49.1% (n = 41) (HR, 3.91; P = 0.014). Additionally, patients with serum S100A9 levels > 0.077 ng/mL (n = 29) had significantly lower survival rates than patients with levels ≤ 0.077 ng/mL (n = 53, HR, 2.52; P = 0.013). S100A9 was expressed on neutrophils and macrophages in BALF from IPF patients as well as α-smooth muscle actin positive cells in the lung tissues.

CONCLUSION

S100A9 is involved in the development and progression of IPF. Moreover, S100A9 levels in BALF and serum may be surrogate markers for IPF diagnosis and survival prediction, particularly when analyzed in combination with neutrophil percentages.

Neutrophil-Related Gene Expression Signatures in Idiopathic Pulmonary Fibrosis: Implications for Disease Characteristic and Identification of Diagnostic Hub Genes

Background

Idiopathic pulmonary fibrosis (IPF) is a disease with unclear etiology and a poor prognosis. Although the involvement of neutrophils in IPF pathogenesis has been suggested, the exact nature of this relationship remains unclear.

Methods

We analyzed data from the Gene Expression Omnibus (GEO) using immune infiltration analysis, weighted gene co-expression network analysis (WGCNA), and consensus cluster analysis. Neutrophil-related genes and hub genes related to neutrophils were identified and differentially expressed between IPF patients and healthy controls. We also validated the expression differences of hub genes in a bleomycin-induced mice model.

Results

Immune infiltration analysis revealed a significantly decreased percentage of neutrophils in the lung tissue of IPF patients compared with healthy controls (P<0.001) in both the train and validation sets. Neutrophil-related genes in IPF were identified by WGCNA, and functional enrichment analysis showed that these genes were mainly involved in the cytokine-cytokine receptor interaction pathway and correlated with lung disease, consistent with DEGs between IPF and healthy controls. Eight hub genes related to neutrophils were identified, including MMP16, ARG1, IL1R2, PROK2, MS4A2, PIR, and ZNF436. Consensus cluster analysis revealed a low neutrophil-infiltrating cluster that was correlated with IPF (P<0.001), and a principal component analysis-generated score could distinguish IPF patients from healthy controls, with an area under the curve of 0.930 in the train set and 0.768 in the validation set. We also constructed a diagnostic model using hub genes related to neutrophils, which showed a reliable diagnostic value with an area under the curve of 0.955 in the train set and 0.995 in the validation set.

Conclusion

Our findings provide evidence of a low neutrophil-infiltrating characteristic in the IPF microenvironment and identify hub genes related to neutrophils that may serve as diagnostic biomarkers for the disease.

Identification of immune biomarkers associated with basement membranes in idiopathic pulmonary fibrosis and their pan-cancer analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease of unknown etiology, characterized by diffuse alveolitis and alveolar structural damage. Due to the short median survival time and poor prognosis of IPF, it is particularly urgent to find new IPF biomarkers. Previous studies have shown that basement membranes (BMs) are associated with the development of IPF and tumor metastasis. However, there is still a lack of research on BMs-related genes in IPF. Therefore, we investigated the expression level of BMs genes in IPF and control groups, and explored their potential as biomarkers for IPF diagnosis. In this study, the GSE32537 and GSE53845 datasets were used as training sets, while the GSE24206, GSE10667 and GSE101286 datasets were used as validation sets. In the training set, seven immune biomarkers related to BMs were selected by differential expression analysis, machine learning algorithm (LASSO, SVM-RFE, Randomforest) and ssGSEA analysis. Further ROC analysis confirmed that seven BMs-related genes played an important role in IPF. Finally, four immune-related Hub genes (COL14A1, COL17A1, ITGA10, MMP7) were screened out. Then we created a logistic regression model of immune-related hub genes (IHGs) and used a nomogram to predict IPF risk. The nomogram model was evaluated to have good reliability and validity, and ROC analysis showed that the AUC value of IHGs was 0.941 in the training set and 0.917 in the validation set. Pan-cancer analysis showed that IHGs were associated with prognosis, immune cell infiltration, TME, and drug sensitivity in 33 cancers, suggesting that IHGs may be potential targets for intervention in human diseases including IPF and cancer.

Granulocyte colony-stimulating factor in bronchoalveolar lavage fluid is a potential biomarker for prognostic prediction of idiopathic pulmonary fibrosis

BACKGROUND/AIMS

Neutrophilia is frequently observed in bronchoalveolar lavage fluid (BALF) of idiopathic pulmonary fibrosis (IPF) patients. Granulocyte colony-stimulating factor (G-CSF) is a potent neutrophil-activating glycoprotein. However, the clinical implications of G-CSF remain poorly understood.in patients with IPF. Therefore, we evaluated the relationship between the G-CSF concentration in BALF and the progression of fibrosis, including in terms of the decline in lung function and long-term survival rate.

METHODS

G-CSF concentrations were measured in BALF using enzyme-linked immunosorbent assay (ELISA). The survival rate was estimated using Kaplan-Meier survival analyses.

RESULTS

G-CSF protein levels were significantly higher in IPF (n = 87; 1.88 [0 to 5.68 pg/mL]), nonspecific interstitial pneumonia (n = 22; 0.58 [0 to 11.64 pg/mL]), and hypersensitivity pneumonitis (n = 19; 2.48 [0.46 to 5.71 pg/mL]) patients than in normal controls (n = 33; 0 [0 to 0.68 pg/mL]) (all p &lt; 0.01). A receiver operating characteristic curve showed a difference in G-CSF levels between IPF and NC (area under the curve, 0.769): The G-CSF cut-off of 0.96 pg/mL indicated 84.9% specificity and 63.2% sensitivity for IPF. The survival rate was significantly lower in the group with G-CSF &gt; 2.872 pg/mL than in the group with ≤ 2.872 pg/mL (hazard ratio, 2.69; p = 0.041). The annual decline in diffusing capacity of the lung for carbon monoxide was positively correlated with the G-CSF level (p = 0.018).

CONCLUSION

G-CSF may participate in the development of IPF and be useful for predicting the prognosis of IPF. Therefore, G-CSF should be analyzed in BALF, in addition to differential cell counts.

Bronchoalveolar cell differential count and the number of asbestos bodies correlate with survival in patients with asbestosis

Objectives

To determine cell differential counts and the number of asbestos bodies (ABs) in bronchoalveolar lavage (BAL) fluid obtained from patients with asbestosis, and to correlate the results with their survival.

Methods

The BAL cell differential counts and ABs from 91 patients with asbestosis were determined. The BAL cell differential counts were analysed in relation to smoking status. BAL cell differential counts and the number of ABs were correlated with the patients’ survivals.

Results

A neutrophilic cell pattern was observed independently of smoking habits with both Papanicolau (8.4%) and May-Grunwald-Giemsa (6.5%) staining. Smoking and a high number of ABs (>2 AB/mL) were associated with high total cell counts and high macrophage and low lymphocyte differential counts. The median survival of the patients was 131.8 months. Shortened survival was associated with high numbers of ABs (78 vs 165 months; p=0.042) and low lymphocyte (77 vs 179 months; p=0.005), high neutrophil (102 vs 180 months; p=0.016) and high eosinophil (104 vs170 months; p=0.007) differential counts.

Conclusion

A neutrophilic cell pattern was evident in BAL from patients with asbestosis. Smoking and ABs both affected the total cell count and the macrophage and lymphocyte differential counts. Several BAL parameters associated with patient survival, suggesting that BAL cell count analyses could be used in the estimation of the prognosis of patients with asbestosis.

Independent Clinical Factors Relevant to Prognosis of Patients with Idiopathic Pulmonary Fibrosis

Background

The prognosis of idiopathic pulmonary fibrosis (IPF) is the worst among all interstitial lung diseases, and is related to the disease itself. Comorbidities or complications can worsen IPF. We assessed the effect of comorbidities on the survival of IPF patients. A retrospective review of patients with IPF was completed.

Material/Methods

Information on demographic features, clinical examination, and comorbidities at baseline were obtained. Then, median, 1-year, and 5-year survival was calculated. A total of 380 patients with IPF admitted to Beijing Chao-Yang Hospital from 1 April 2002 to 31 March 2015 were followed up until December 2016.

Results

Of these 380 patients, 71.9% died during the study period. Median survival was 2.25 years and overall 5-year survival was 28.5%. Also, 86.3% of patients were males. A total of 248 cases underwent lung function tests, and 178 patients underwent bronchoalveolar lavage (BAL). Multivariate analyses showed that forced expiratory volume in 1 second/forced vital capacity (FVC), diffusing capacity of the lungs for carbon monoxide percent predicted, FVC% predicted, the number of macrophages, neutrophils, and lymphocytes in BAL fluid, pulmonary hypertension, hypoxemia, and hydropower disorder were independent prognostic indicators of IPF, GAP gender (G), age (A), and 2 pulmonary physiological parameters (P) model can help to predict prognosis of IPF.

Conclusions

Spirometry, GAP model, and BAL are helpful to forecast the prognosis of IPF. IPF patients also suffering from pulmonary arterial hypertension, hypoxemia, and hydropower disorder have a poor prognosis.

Resolution of bleomycin-induced murine pulmonary fibrosis via a splenic lymphocyte subpopulation

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with high mortality, and the pathogenesis of the disease is still incompletely understood. Although lymphocytes, especially CD4⁺CD25⁺FoxP3⁺ regulatory T cells (Tregs), have been implicated in the development of IPF, contradictory results have been reported regarding the contribution of Tregs to fibrosis both in animals and humans. The aim of this study was to investigate whether a specific T cell subset has therapeutic potential in inhibiting bleomycin (BLM)-induced murine pulmonary fibrosis.

Methods

C57BL/6 mice received BLM (100 mg/kg body weight) with osmotic pumps (day 0), and pulmonary fibrosis was induced. Then, splenocytes or Tregs were adoptively transferred via the tail vein. The lungs were removed and subjected to histological and biochemical examinations to study the effects of these cells on pulmonary fibrosis, and blood samples were collected by cardiac punctures to measure relevant cytokines by enzyme-linked immunosorbent assay. Tregs isolated from an interleukin (IL)-10 knock-out mice were used to assess the effect of this mediator. To determine the roles of the spleen in this model, spleen vessels were carefully cauterized and the spleen was removed either on day 0 or 14 after BLM challenge.

Results

Splenocytes significantly ameliorated BLM-induced pulmonary fibrosis when they were administered on day 14. This effect was abrogated by depleting Tregs with an anti-CD25 monoclonal antibody. Adoptive transfer of Tregs on day 14 after a BLM challenge significantly attenuated pulmonary fibrosis, and this was accompanied by decreased production of fibroblast growth factor (FGF) 9-positive cells bearing the morphology of alveolar epithelial cells. In addition, BLM-induced plasma IL-10 expression reverted to basal levels after adoptive transfer of Tregs. Moreover, BLM-induced fibrocyte chemoattractant chemokine (CC motif) ligand-2 production was significantly ameliorated by Treg adoptive transfer in lung homogenates, accompanied by reduced accumulation of bone-marrow derived fibrocytes. Genetic ablation of IL-10 abrogated the ameliorating effect of Tregs on pulmonary fibrosis. Finally, splenectomy on day 0 after a BLM challenge significantly ameliorated lung fibrosis, whereas splenectomy on day 14 had no effect.

Conclusions

These findings warrant further investigations to develop a cell-based therapy using Tregs for treating IPF.

Clusterization of patients with idiopathic pulmonary fibrosis with chemokine receptors: a possible role in the diagnostic work-up of idiopathic pulmonary fibrosis?

Background and objective: Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible interstitial lung disease whose diagnosis often requires surgical lung biopsies (SLB) in cases without consistent radiological findings. We previously published that the expression of the chemokine receptors CXCR3 and CCR4 on T cells is significantly different in bronchoalveolar lavage (BAL) of IPF patients from other interstitial lung diseases. The aim of the study was to evaluate cut-off values of CXCR3 and CCR4 receptors expressed on bronchoalveolar lavage (BAL) and peripheral blood (PB) T cells useful for a differential diagnosis. Methods: Ninety-three patients were enrolled: 35 IPF, 36 interstitial lung diseases (nIPF) and 22 sarcoidosis. CXCR3 and CCR4 were evaluated on BAL and PB T lymphocytes with flow cytometry. Results: Among PB and BAL variables considered, the values of the ratio of BAL and PB CXCR3 on CD4 cells were clustered in the most informative way to obtain a classification rule for the diagnosis of patients without steroid therapy (n = 66/93). Patients with a CXCR3 ratio BAL/PB on CD4 T cells lower or equal than 1.43 were assigned to the IPF group with sensitivity = 0.87 and specificity = 0.90. All the other variables considered showed lower sensitivity and specificity in discriminating IPF patients. Conclusions: The evaluation of chemokine receptors on BAL and PB T lymphocytes could aid to discriminate IPF in subjects without steroid therapy, particularly in those patients with a high-resolution computed tomography (HRCT) non typical for Usual Interstitial Pneumonia (UIP). (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 35-43).

Risk factors for an acute exacerbation of idiopathic pulmonary fibrosis

Background

Acute exacerbations of idiopathic pulmonary fibrosis are major causes of morbidity and mortality among patients with idiopathic pulmonary fibrosis. However, acute exacerbations remain unpredictable. The aim of this study was to investigate risk factors for acute exacerbations of idiopathic pulmonary fibrosis.

Methods

We performed a retrospective cohort study of patients with idiopathic pulmonary fibrosis who visited our institutions from January 1999 to September 2014. We investigated risk factors for acute exacerbations in patients with idiopathic pulmonary fibrosis diagnosed retrospectively based on the official 2011 idiopathic pulmonary fibrosis ATS/ERS/JRS/ALAT Update Statement.

Results

The idiopathic pulmonary fibrosis study cohort included 65 subjects. The median follow-up period was 2.6 years. During follow-up, 24 patients (36.9 %) experienced acute exacerbations. A Kaplan-Meier curve demonstrated that the 1-year, 2-year, and 3-year incidences of acute exacerbation were 9.6, 19.2 and 31.0 %, respectively. Acute exacerbation exerted a significant impact on overall survival among those with the disease. A log-rank test showed that baseline cardiovascular diseases, higher GAP (gender, age, physiology) stage (≥II), higher serum lactate dehydrogenase level (≥180 U/L), higher serum surfactant protein-D level (≥194.7 ng/mL), higher neutrophil (≥1.77 %) and eosinophil (≥3.21 %) percentages in bronchoalveolar lavage fluid samples, and treatment with an immunosuppressive agent after diagnosis were associated with poor acute exacerbation-free probability. In the Cox analysis adjusted for treatment with an immunosuppressive agent, baseline cardiovascular diseases, higher GAP stage (≥II), and higher eosinophil percentage (≥3.21 %) in bronchoalveolar lavage fluid samples were predictors of an acute exacerbation of idiopathic pulmonary fibrosis.

Conclusions

This study demonstrated that baseline cardiovascular diseases, higher GAP stage (≥II), and higher eosinophil percentage (≥3.21 %) in bronchoalveolar lavage fluid samples were associated with the onset of an acute exacerbation of idiopathic pulmonary fibrosis.

The pathogenesis of bleomycin-induced lung injury in animals and its applicability to human idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating disease of unknown etiology, for which there is no curative pharmacological therapy. Bleomycin, an anti-neoplastic agent that causes lung fibrosis in human patients has been used extensively in rodent models to mimic IPF. In this review, we compare the pathogenesis and histological features of human IPF and bleomycin-induced pulmonary fibrosis (BPF) induced in rodents by intratracheal delivery. We discuss the current understanding of IPF and BPF disease development, from the contribution of alveolar epithelial cells and inflammation to the role of fibroblasts and cytokines, and draw conclusions about what we have learned from the intratracheal bleomycin model of lung fibrosis.

Bronchoalveolar lavage total cell count in interstitial lung diseases--does it matter?

Bronchoalveolar lavage (BAL) is a useful technique for differential diagnosis of various interstitial lung diseases (ILDs) and is usually realized by analysis of the differential cell count. This study was conducted to estimate the value of bronchoalveolar lavage fluid (BALF) total cell count (TCC) in the diagnosis of ILD. We analyzed 237 BAL samples from patients with ILD: sarcoidosis (SA), idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP), hypersensitivity pneumonitis (HP), chronic eosinophilic pneumonia (CEP), and smoking-related ILD (sr-ILD). The control group consisted of 30 healthy volunteers. The statistical analysis revealed significant differences in the BALF TCC between healthy controls and patients with SA, IPF, HP, COP, sr-ILD, and eosinophilic disorders (mean values 6.9 vs. 14.5, 22.5, 22.8, 20.7, 64.5, and 27.3 × 10(6), respectively). Logistic regression revealed a significant relation between the TCC and ILD diagnosis. We conclude that the TCC, as well as the value of total number of inflammatory cells, should be reported in the description of BAL.

Idiopathic pulmonary fibrosis-an epidemiological and pathological review

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease (ILD) affecting the pulmonary interstitium. Other forms of interstitial lung disease exist, and in some cases, an environmental etiology can be delineated. The diagnosis of IPF is typically established by high-resolution CT scan. IPF tends to have a worse prognosis than other forms of ILD. Familial cases of IPF also exist, suggesting a genetic predisposition; telomerase mutations have been observed to occur in familial IPF, which may also explain the increase in IPF with advancing age. Alveolar epithelial cells are believed to be the primary target of environmental agents that have been putatively associated with IPF. These agents may include toxins, viruses, or the autoantibodies found in collagen vascular diseases. The mechanism of disease is still unclear in IPF, but aberrations in fibroblast differentiation, activation, and proliferation may play a role. Epithelial-mesenchymal transition may also be an important factor in the pathogenesis, as it may lead to accumulation of fibroblasts in the lung and a disruption of normal tissue structure. Abnormalities in other components of the immune system, including T cells, B cells, and dendritic cells, as well as the development of ectopic lymphoid tissue, have also been observed to occur in IPF and may play a role in the stimulation of fibrosis that is a hallmark of the disease. It is becoming increasingly clear that the pathogenesis of IPF is indeed a complex and convoluted process that involves numerous cell types and humoral factors.

Bronchoalveolar lavage improves diagnostic accuracy in patients with diffuse lung disease

Bronchoalveolar lavage (BAL) is an established diagnostic tool in diffuse parenchyma lung disease. The objective of the present study was designed to investigate whether immunophenotyping affects BAL results and improves diagnostic accuracy. BAL from 61 patients was included in the study. The patients were also submitted to transbronchial biopsy, with a final diagnosis of granulomatous disease [tuberculosis (TB), n = 20; sarcoidosis (SARC), n = 3; and hypersensitivity pneumonitis (HP), n = 4]; idiopathic interstitial pneumonias (IIPs) [idiopathic pulmonary fibrosis (IPF), n = 9; organizing pneumonia (OP), n = 17]; and lung cancer (LC), n = 8. Immunohistochemistry and histomorphometry were used to identify and quantify type 1 and type 2 alveolar epithelial cells, macrophages, CD3+T-cells, CD4+T-cells, CD8+T-cells, and CD20+B-cells in BAL. These markers were correlated with a database and pulmonary function tests. The cellular, inflammatory, and immune components of BAL varied among the diagnostic groups and were negatively correlated with age and smoking history. An increased quantity of lymphocyte surface markers CD3 (P < 0.05) and CD20 (P = 0.01) was seen in IIPs. Patients with a pattern of OP had a higher proportion of type 2 alveolar epithelial cells; patients with SARC had a higher density of CD20+B-cells and CD4+T-helper cells; and patients with HP had a higher proportion of CD8+T-cytotoxic cells. A positive association was found between the density of type I alveolar epithelial cells and forced vital capacity. The immunophenotyping affects the cellular, inflammatory, or immune constituents of BAL and improved the diagnostic accuracy in diffuse parenchymal lung disease.

Copy number variation of FCGR3B is associated with susceptibility to idiopathic pulmonary fibrosis

BACKGROUND

Several genes exhibit copy number variation (CNV), including FCGR3B which encodes the IgG receptor FcγRIIIb. Engagement of Fcγ receptors by IgG complexes may contribute to the pathogenesis of idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

To investigate whether FCGR3B CNV is associated with susceptibility to IPF.

METHODS

In a case-control study we compared FCGR3B copy number in 142 patients with IPF and in 221 controls by real-time quantitative PCR using CD36 as gene copy control.

RESULTS

Significantly increased FCGR3B:CD36 ratio was evident in the IPF cohort compared to controls (p = 0.009). Association of FCGR3B copy number with IPF susceptibility was further confirmed by a likelihood ratio statistical approach (p = 0.003). FCGR3B copy number assignment based on FCGR3B:CD36 ratios revealed significant skewing in the distribution of FCGR3B copy number between IPF patients and controls. In the IPF cohort, there was increased frequency of >2 FCGR3B copies compared to controls (0.30 vs. 0.19; χ(2) = 9.27; d.f. 2; p = 0.0097). The presence of >2 FCGR3B copies was associated with higher risk of IPF (p = 0.01, OR: 1.914, 95% CI: 1.17-3.12).

CONCLUSIONS

These findings support an association of FCGR3B copy number with susceptibility to IPF and propose a novel role for Fcγ receptors in IPF disease pathogenesis.

T regulatory cells and attenuated bleomycin-induced fibrosis in lungs of CCR7-/- mice

Background

C-C chemokine receptor (CCR)7 is a regulator of dendritic cell and T cell migration, and its role in tissue wound healing has been investigated in various disease models. We have previously demonstrated that CCR7 and its ligand, chemokine (C-C motif) ligand (CCL)21, modulates wound repair in pulmonary fibrosis (PF) but the mechanism of this is unknown. The objective of this study was to investigate whether the absence of CCR7 protects against bleomycin (BLM)-induced PF. CCR7^-/- mice failed to mount a fibrotic pulmonary response as assessed by histologic collagen staining and quantification by hydroxyproline. We hypothesized that the prominent characteristics of CCR7^-/- mice, including elevated levels of cytokine and chemokine mediators and the presence of bronchus-associated lymphoid tissue (BALT) might be relevant to the protective phenotype.

Results

Pulmonary fibrosis was induced in CCR7^+/+ and CCR7^-/- mice via a single intratracheal injection of BLM. We found that the lung cytokine/chemokine milieu associated with the absence of CCR7 correlated with an increase in BALT, and might be attributable to regulatory T cell (Treg) homeostasis and trafficking within the lungs and lymph nodes. In response to BLM challenge, CCR7^-/- mice exhibited an early, steady increase in lung CD4⁺ T cells and increased CD4⁺ CD25⁺ FoxP3⁺ Tregs in the lungs 21 days after challenge. These findings are consistent with increased lung expression of interleukin-2 and indoleamine 2,3-dioxygenase in CCR7^-/- mice, which promote Treg expansion.

Conclusions

Our study demonstrates that the protective phenotype associated with BLM-treated CCR7^-/- mice correlates with the presence of BALT and the anchoring of Tregs in the lungs of CCR7^-/- mice. These data provide novel evidence to support the further investigation of CCR7-mediated Treg trafficking in the modulation of BLM-induced PF.

Bronchoalveolar lavage in idiopathic pulmonary fibrosis: what does it tell us?

Bronchoalveolar lavage (BAL) has only a limited role in diagnosis of idiopathic pulmonary fibrosis (IPF). A finding of raised neutrophils (>5%) and eosinophils (>2%) is characteristic but not diagnostic of IPF. BAL cell count does not clearly differentiate between fibrotic non-specific interstitial pneumonia and IPF either diagnostically or prognostically. BAL in IPF should be considered in all patients with suspected infection, malignancy or acute exacerbations. In such cases, it may be diagnostic. Because of few and conflicting results BAL fluid analysis has very little clinical relevance determining prognosis and response to treatment in IPF.

BAL in the diagnosis of smoking-related interstitial lung diseases: review of literature and analysis of our experience

The group of interstitial lung diseases (ILDs) is formed by respiratory tract disorders, whose aetiology is unknown in the majority of cases, the clinical course differs and the prognosis is generally serious. Some of the ILDs have a potential relation to tobacco smoking and are known as smoking-related ILDs (sr-ILD). Bronchoalveolar lavage fluid (BALF) examination is one of the initial procedures in the diagnosis of ILD. Despite the fact that histological confirmation is the gold standard in ILD diagnosis in many studies, the number of reported biopsies was low. In this review we present the results of BALF examinations of patients with sr-ILD and discuss their value in the differential diagnosis with other types of ILD. An extremely high total cell count (about 50 x 10(6) cells) with significant predominance of pigmented alveolar macrophages is a characteristic pattern of BALF in sr-ILD. The greatest challenge in BALF cytology interpretation is to distinguish sr-ILD and idiopathic pulmonary fibrosis (IPF). IPF is characterised by an elevated proportion and absolute count of lymphocytes and neutrophils; in addition, BALF lymphocytosis is higher in non-specific interstitial pneumonia than in usual interstitial pneumonia (UIP). The population of alveolar macrophage of patients with sr-ILD differs markedly from the foamy and vacuolated cells that predominate in IPF/UIP. Thus, the absence of pigmented cells rather excludes sr-ILD and indicates other types of ILD. To summarise, the place of BALF in the diagnosis of sr-ILD seems to be established.

Significance of bronchoalveolar lavage for the diagnosis of idiopathic pulmonary fibrosis

RATIONALE

According to the 2002 ATS/ERS Consensus Classification, a confident diagnosis of idiopathic pulmonary fibrosis (IPF) without surgical lung biopsy is made with consistent clinical/physiological findings and the typical features on high-resolution computed tomography (HRCT). Bronchoalveolar lavage (BAL) and/or transbronchial biopsy, one of four major criteria in the 2000 ATS/ERS IPF Statement, was no more essential in the diagnostic algorithm of 2002 ATS/ERS Consensus Classification.

OBJECTIVES

To evaluate the additional utility of BAL for the diagnosis of IPF.

METHODS

A total of 101 patients with suspected IPF on HRCT were studied. Twenty-seven patients were excluded because of lack of functional impairment (n = 20), an underlying condition causing fibrosis (n = 5), or a clinical history inconsistent with IPF (n = 2). The remaining 74 patients met all the criteria recommended in the 2002 ATS/ERS Consensus Classification for making a diagnosis in the absence of surgical biopsy. The final diagnosis was made with further examinations, including pathological analysis, in patients who showed inconsistent findings for IPF on BAL.

MEASUREMENTS AND MAIN RESULTS

A cut-off level of 30% for lymphocytes in BAL demonstrated a favorable discriminative power for the diagnosis of IPF. Six of the 74 patients (8%) showed a lymphocytosis of 30% or greater in BAL. Their final diagnoses were idiopathic nonspecific interstitial pneumonia (n = 3) and extrinsic allergic alveolitis (n = 3). The change in perception of the diagnosis was validated by a surgical biopsy in two cases and by subsequent outcome in four cases.

CONCLUSIONS

BAL lymphocytosis changed the diagnostic perception in six of 74 patients who would have been misdiagnosed as having IPF without BAL.

The role of inflammation in the pathogenesis of idiopathic pulmonary fibrosis

The role of inflammation in idiopathic pulmonary fibrosis (IPF) is controversial. If inflammation were critical to the disease process, lung pathology would demonstrate an influx of inflammatory cells, and that the disease would respond to immunosuppression. Neither is true. The classic pathology does not display substantial inflammation, and no modulation of the immune system is effective as treatment. Recent data suggest that the pathophysiology of the disease is more a product of fibroblast dysfunction than of dysregulated inflammation. The role of inflammation in disease pathogenesis comes from pathology from atypical patients, biologic samples procured during exacerbations of the disease, and careful examination of biologic specimens from patients with stable disease. We suggest that inflammation is indeed a critical factor in IPF and propose five potential nontraditional mechanisms for the role of inflammation in the pathogenesis of IPF: the direct inflammatory hypothesis, the matrix hypothesis, the growth factor-receptor hypothesis, the plasticity hypothesis, and the vascular hypothesis. To address these, we review the literature exploring the differences in pathology, prognosis, and clinical course, as well as the role of cytokines, growth factors, and other mediators of inflammation, and last, the role of matrix and vascular supply in patients with IPF.

Bronchoalveolar lavage in interstitial lung diseases: does the recovery rate affect the results?

BACKGROUND

Bronchoalveolar lavage (BAL) is an established diagnostic tool in interstitial lung diseases. BAL frequently yields findings of diagnostic value and at times even confirmatory diagnostic results.

OBJECTIVES

The present study has been designed to investigate whether the recovery rate affects BAL results relative to the instilled volume.

METHODS

Six hundred and eighteen patients with the following diagnoses were included into the study: 236 with sarcoidosis, 85 with idiopathic pulmonary fibrosis, 83 with cryptogenic organizing pneumonitis, 64 with connective tissue disease affecting the lungs, 54 with respiratory bronchiolitis with interstitial lung disease, 51 with extrinsic allergic alveolitis and 45 control patients. BAL was performed during flexible bronchoscopy with an irrigation volume of 100 ml 0.9% saline solution in 5 aliquots of 20 ml each. Only patients with a recovery of at least 30 ml were evaluated. Initially, the entire patient population was analysed, followed by an analysis within the different diagnostic groups and a comparison between patients with a high (>50 ml) and low (< or =50 ml) recovery rate.

RESULTS

The recovery rate varied between the diagnostic groups (p < 0.001) and was negatively correlated with age (r = -0.21, p < 0.001) and smoking history (r = -0.11, p < 0.035). There were no correlations with inspiratory vital capacity (%pred.; p = 0.26) and forced expiratory volume in 1 s (%pred.; p = 0.15), but a positive correlation with the index (forced expiratory volume in 1 s/inspiratory vital capacity) x 100 (r = 0.23, p < 0.001). The cellular and non-cellular constituents of BAL were not affected by the recovery: cells/millilitre BAL (p = 0.71), relative proportion of macrophages (p = 0.92), lymphocytes (0 = 0.33), neutrophils (p = 0.14) and eosinophils (p = 0.11), albumin concentration (p = 0.13), and proportion of albumin in total protein (p = 0.06). The same applied for the lymphocyte surface markers CD4 (p = 0.72) and CD8 (p = 0.53). In the group with a high recovery rate, patients with sarcoidosis had a lower proportion of eosinophils (p = 0.04) and patients with cryptogenic organizing pneumonitis a higher concentration of albumin (p = 0.02) and lymphocytes (p = 0.007). Otherwise, no further differences were detected.

CONCLUSIONS

The recovery rate hardly affected the cellular and non-cellular constituents of BAL at a lower limit of 30% of the instilled volume.

Inflammatory Cell Phenotyping of the Pulmonary Interstitium in Idiopathic Interstitial Pneumonia

BACKGROUND

Several studies have implicated the role of inflammation in the pathogenesis of lung damage in idiopathic interstitial pneumonias (IIPs). Investigations of inflammatory cells in IIP have show that eosinophils, neutrophils and T cells may be associated with a poorer prognosis.

OBJECTIVES

The aim of our study was to map, by quantitative analysis, the number of inflammatory cells in the lung tissue of patients with non-specific interstitial pneumonia/non-specific interstitial pneumonia (NSIP/NSIP), acute interstitial pneumonia/diffuse alveolar damage (AIP/DAD) and idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) and to correlate them with lung function tests and survival.

METHODS

After immunohistochemical staining, we quantified the content of inflammatory cells [macrophages, neutrophils (elastase+), plasma cells, and CD3, CD4 and CD8 T lymphocytes (TLs)] in 20 NSIP, 20 DAD and 20 UIP surgical lung biopsies.

RESULTS

The total density of inflammatory cells was significantly increased in DAD and NSIP when compared to UIP (p = 0.04). TLs were increased in DAD and NSIP when compared to UlP lungs (p < 0.05). The density of inflammatory cells in UIP showed significant differences in normal, intervening and dense fibrosis areas (p < 0.05). The most numerous cells infiltrating the mural fibrosis and honeycombing areas were plasma cells, neutrophils (elastase+), CD20+, CD3+, CD4+ and CD8+ (p < 0.05). In UIP, CD3+ TLs were directly correlated with forced expiratory volume in 1 s/forced vital capacity ratio x 100 (p = 0.05). CD68+ cells presented a significant positive correlation with the forced expiratory volume in 1 s (p = 0.04); neutrophil (elastase+) cells significantly correlated with residual volume (p = 0.02), residual volume/total lung capacity (p = 0.04) and carbon monoxide transfer factor (p = 0.03). The most important predictor of survival in UIP was CD3+ TLs (p = 0.05).

CONCLUSION

The total density of inflammatory cells and lymphocytes presents a different distribution within the pulmonary parenchyma in AIP/DAD, NSIP/NSIP and IPF/UIP evolutionary adapted responses to injury. There is a localized distribution of inflammation in the normal, intervening and dense fibrosis areas of UIP for CD3+, associated with a lethal deterioration of the pulmonary function and poor survival. Our findings provide further evidence of the importance of inflammation in the pathophysiology of IIPs.