The utility of bronchoalveolar lavage in the evaluation of interstitial lung diseases: A clinicopathological perspective

Bronchoalveolar lavage (BAL) is a noninvasive and well-tolerated procedure that is performed with a fiberoptic bronchoscope in the wedged position within a selected bronchopulmonary segment. After it was introduced to clinical practice, BAL rapidly gained acceptance in a large number of centers as a procedure that could be applied to the clinical evaluation of patients with various pulmonary disorders, especially the group of interstitial lung diseases (ILD). Cytological and flow cytometric analysis of BAL fluid in ILD is done with knowledge of the clinical presentation and radiological findings. BAL typically reveals variations in the types and numbers of nucleated immune cells and acellular components in patients with ILD, which differ from those seen in normal control subjects. Many clinicians currently use this technique as a guide in the differential diagnoses of ILD; it can also be used to monitor the course of disease and possible response to therapeutic interventions. This article summarizes current clinicopathological information concerning the use of BAL by pulmonologists and pathologists.     

MRP14 is elevated in the bronchoalveolar lavage fluid of fibrosing interstitial lung diseases

Pulmonary fibrosis is defined by an overgrowth of fibroblasts and extracellular matrix deposition, and results in respiratory dysfunction that is often fatal. It is the end stage in many chronic inflammatory interstitial lung diseases (ILD) such as sarcoidosis and idiopathic pulmonary fibrosis (IPF). The myeloid‐related proteins (MRPs) belong to the S100 family of calcium‐binding proteins and are highly expressed by neutrophils, macrophages and epithelial cells during chronic inflammation. MRP14 stimulates fibroblast proliferation in vitro and is expressed in granulomas from sarcoidosis patients. We hypothesized that MRP14 may be a biomarker for fibrotic interstitial lung diseases. The objective of this study was to investigate whether levels of MRP14 in the bronchoalveolar lavage fluid (BALF) of patients with sarcoidosis and IPF correlate with clinical parameters. We used an enzyme‐linked immunosorbent assay (ELISA) to measure MRP14 in BALF of 74 sarcoidosis patients, 54 IPF patients and 19 controls. Mean BALF levels of MRP14 were elevated significantly in IPF (P < 0·001) and sarcoidosis (P < 0·05) patients compared to controls. MRP14 levels were associated linearly with sarcoidosis disease severity based on chest radiographic stage. Moreover, BALF MRP14 levels were correlated inversely with diffusion capacity and forced vital capacity in sarcoidosis patients. In IPF patients, a correlation with BALF neutrophil percentage was found. In conclusion, BALF MRP14 levels are elevated in IPF and sarcoidosis and are associated with disease severity in sarcoidosis. The results support the need for further studies into the role of MRP14 in the pathogenesis of lung fibrosis.     

Diagnostic value of combined bronchoalveolar lavage and transbronchial lung biopsy

The aim of our study was to assess the diagnostic value of combined transbronchial lung biopsy (TBB) and bronchoalveolar lavage (BAL) in non-immunosuppressed patients, who underwent routine bronchoscopy for evaluation of interstitial lung disease. We examined routinely sampled and processed material from 87 patients from two peripheral pulmological centers and compared the lavage and biopsy results to the final clinical outcome. 22 of these patients showed no evidence of interstitial lung disease during the course of follow-up. Sufficient lung parenchyma was present in 81 of 91 biopsy specimens (including four repeat biopsies), and 79 of 91 BAL samples were considered adequate. The combination of BAL and TBB was more efficient (efficiency 80.3% vs. 67.9% in TBB and 64.6% in BAL) than either method alone. Sensitivity showed a similar increase from 58.8% in TBB and 73.9% in BAL to 79.5% for both combined. Specificity for BAL was a low 60.7% due to contamination by inflammatory cells from upper airways, whereas specificity for TBB was 100%. We conclude that the combination of bronchoalveolar lavage and transbronchial lung biopsy is a valuable tool in the evaluation of interstitial lung disease and should be employed whenever possible.     

Elevated matrilysin levels in bronchoalveolar lavage fluid do not distinguish idiopathic pulmonary fibrosis from other interstitial lung diseases

Microarray studies have shown that matrilysin or matrix metalloproteinase (MMP)-7 is highly upregulated in the lungs of patients with idiopathic pulmonary fibrosis (IPF), but MMP-7 protein expression has not been systematically compared between IPF and other interstitial lung diseases. MMP-7 levels in bronchoalveolar lavage fluid (BALF) were compared to corresponding samples from nonspecific interstitial pneumonia (NSIP), sarcoidosis, and healthy controls. MMP-7 levels in the BALF were determined by ELISA and localization of MMP-7 in the lung tissue by immunohistochemistry. MMP-7 was similarly elevated in the BALF of all these disorders compared to healthy controls (p=0.007). Even control subjects with prolonged cough displayed a tendency towards elevated MMP-7 expression. There was a negative correlation between BALF MMP-7 levels and forced expiratory vital capacity (r=-0.348, p=0.02, n=42). In IPF lung, MMP-7 immunoreactivity appeared predominantly in the fibrotic parenchyma and arterial wall. In sarcoidosis and NSIP, prominent MMP-7 immunoreactivity was found in areas of inflammation. These results demonstrate that elevated BALF MMP-7 is not restricted to IPF alone but is also observed in other interstitial lung diseases and cannot be used as a differential diagnostic marker for IPF.     

The diagnostic importance of the bronchoalveolar lavage in lymphocytic alveolitis

Multidisciplinary concertation is mandatory in order to assess interstitial pneumonias. The study of the bronchoalveolar lavage helps evoking a diagnosis according to the lavage profile. In lymphocytic alveolitis, immunocytochemistry, or in flux cytometry are necessary in order to identify the different clusters of lymphocytes implicated. Our objective was to evaluate the profile of 31 lymphocytic alveolitis using 2 different techniques which are the immunocytochemistry and the in flow cytometry in order to evaluate the efficacy of each technique and to compare the different results to the final diagnoses. We describe a retrospective study about 31 patients admitted to our hospital in order to explore an interstitial pneumonia between January and July 2014. Bronchial endoscopy and bronchoalveolar lavage were performed in all cases. The sensitivity of the in flow cytometry was estimated to 53% and its specificity reached 33%. On the other hand, the immunocytochemistry presented a specificity of 42.8% and a sensitivity of 42.8%. The final diagnoses retained consisted in sarcoidosis in 12 cases, infectious pneumonia in 10 cases, hypersensitivity pneumonia in 3 cases, cryptogenic pneumonia in 3 cases, idiopathic fibrosis in 2 cases, and adenocarcinoma in 1 case. The relevance of both techniques depends on many factors. They necessitate an available material, well-trained technicians, and experimented pathologists.     

Diagnostic value of bronchoalveolar lavage in immunodepressed patients

Bronchoalveolar lavage, a non invasive study of the function of the lung in cases of interstitial pneumonia, offers remarkable information in immunocompromised patients, particularly as far as the search for pathogens is concerned. The different steps of the technique are reported; the special care of the lavage related to patients' condition is enhanced.     

Stromal cells can be cultured and characterized from diagnostic bronchoalveolar fluid samples obtained from patients with various types of interstitial lung diseases

Increased proliferation of stromal cells is a typical feature encountered in several lung diseases. The objective of this study was to evaluate the success of standardized process for culturing stromal cells from small volumes of diagnostic bronchoalveolar lavage (BAL) fluid samples collected from various patients and to characterize the cultured cells. Small volumes (average 15 mL) of BAL fluid samples were collected from 98 patients who underwent bronchoscopy and BAL for diagnostic purposes. The cells were cultured in vitro and characterized by immunohistochemistry, electron microscopy, flow cytometry and differentiation tests. Cells could be cultured from 62% of samples with the success rate varying with the disease (p = 0.003). Cultures from samples of the patients with idiopathic pulmonary fibrosis, non‐specific interstitial pneumonia, connective tissue disorder associated interstitial lung disease and allergic alveolitis had a higher success rate than samples derived from control lung (p < 0.001, 0.03, 0.03 and 0.044, respectively). Smokers had a higher success rate compared with non‐smokers (p = 0.035). The cultured cells were fibroblasts or myofibroblasts, but shared also similarities with progenitor‐type cells. The study shows that mesenchymal cells can be cultured and studied from small volumes of diagnostic BAL fluid samples from patients with several different types of lung diseases.     

IL-9 and IL-9 receptor expression in lymphocytes from bronchoalveolar lavage fluid of patients with interstitial lung disease

IntroductionIL-9, mainly produced by T helper 9 (Th9) cells, promotes allergic airway inflammation and remodeling through the interaction with its receptor (IL-9R). Th9 cells and IL-9 have also been implicated in tissue fibrosis and autoimmunity pathways. However, the role of IL-9/IL-9R in the pathogenesis of interstitial lung disease (ILD) is unknown.AimTo evaluate IL-9/IL-9R expression in bronchoalveolar lavage fluid (BALF) lymphocytes of patients with various ILDs.MethodsConsecutive patients with ILD, who underwent BAL for diagnostic purposes, were studied. As control group, consecutive patients without evidence of ILD were included. Immunocytochemical staining of BALF lymphocytes for IL-9 and IL-9R was performed and evaluated by two independent readers.Results45 patients, of them 8 had idiopathic pulmonary fibrosis (IPF), 12 nonspecific interstitial pneumonia (NSIP), 10 sarcoidosis, 9 hypersensitivity pneumonitis (HP), 6 cryptogenic organizing pneumonia (COP), and 24 controls were studied. In the ILD group, the highest BALF lymphocyte count was seen in HP followed by NSIP, COP, sarcoidosis, and IPF (p < 0.05 for HP vs IPF). The highest percentages of IL-9 and IL-9R positive lymphocytes were seen in COP. Conversely, NSIP showed the lowest rate of IL-9, and sarcoidosis the lowest rate of IL-9R positive lymphocytes. Only in NSIP, a direct correlation between IL and 9 and IL-9R positive lymphocytes was seen (r = 0.639, p = 0.025).ConclusionBALF lymphocytes IL-9 and IL-9R expression differs between various ILDs and could reflect different pathogenetic mechanisms.     

Smoking-related interstitial lung diseases

In pulmonary pathology, a wide spectrum of morphological changes is related to the consequences of smoking, and recognizing them on surgical specimens and on small transbronchial biopsies represents a challenge for the pathologist. Respiratory bronchiolitis, also referred to as smoker's bronchiolitis, is a common histologic feature found in the lung tissue of cigarette smokers. When identified as the sole histopathologic finding in the clinical setting of symptomatic interstitial lung disease, a diagnosis of respiratory bronchiolitis-interstitial lung disease is made. Since smoking is recognized to cause a variety of histologic patterns encompassing respiratory bronchiolitis, respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia and pulmonary Langerhans cell hystiocytosis, smoking-related interstitial lung disease may be a useful concept to keep in mind for the pathologists. The relationship of smoking with each of these entities has been largely established on the basis of epidemiologic evidence. Although they have been retained as distinct and separate conditions in various classifications of interstitial lung diseases, these entities share a number of clinical, radiologic, and pathologic features suggesting that they represent a spectrum of patterns of interstitial lung disease occurring in predisposed individuals who smoke. Evaluation of histologic features, particularly in surgical lung biopsy samples, is important in making the distinction between these disorders. However, even after tissue biopsy, it may sometimes be difficult to clearly separate these entities. Recently, respiratory bronchiolitis-interstitial lung disease with fibrosis has been described and postulated that this is a smoking-related condition distinct from fibrotic non-specific interstitial pneumonia.     

Assessment of local cellular immunity in lung cancer by bronchoalveolar lavage

Summary Small cell lung cancer (SCLC) is the most malignant of the pulmonary neoplasms and is associated with a poor local cellular immune response. 16 patients with non small cell lung cancer (NSCLC) and 11 patients with SCLC underwent bronchoalveolar lavage (BAL) in the lung which harbored the tumor in order to investigate the lymphocyte surface antigens utilizing the immunoperoxidase technique. Analysis of blood lymphocytes was performed in parallel. 8 patients with previous sarcoidosis in complete remission who underwent BAL and 10 normal blood donors served as controls.Among blood lymphocytes the CD3⁺, CD4⁺ and CD16⁺ cell populations were elevated significantly and the T4/T8 ratio was elevated in NSCLC patients, but only CD16⁺ were augmented in SCLC. Cell populations expressing the activation markers transferrin (TF) receptor, interleukin-2 (IL-2) receptor and the very late antigen VAL-1 were also increased in NSCLC, while SCLC was associated with antigen distributions similar to controls. No differences between the cohorts were seen in the expression of human leukocyte antigen (HLA)-DR. In BAL the population of CD3⁺ and CD4⁺ cells were reduced in SCLC and the T4/T8 ratio was diminished in contrast to controls and NSCLC patients, whereas these two latter groups did not differ from each other. The distribution pattern of CD16, TF receptor and IL-2 receptor in the study groups resembled that of cells of the blood stream, but CD16⁺ natural killer cells were additionally down regulated to control values in SCLC. No differences were seen in the distribution of VLA-1. HLA-DR⁺ cells were clearly elevated in both cancer groups.In general NSCLC was associated with a shift to higher relative numbers of immunocompetent and activated cells. This was most probably attributable to an immune response to neoplastic growth. This shift was largely lacking in SCLC. The analysis of lymphocytes from the periphery of the target organ emerged as a sensitive tool for the study of cellular immunity in lung cancer and showed many similarities to circulating blood cells. However, the analysis of natural killer cells and HLA-DR suggested a dissection of cellular immune response between blood and lung in pulmonary cancer. A depressive interaction between the tumor and the cellular host immune response may contribute to the exceptional malignancy of SCLC.Abbreviations BAL bronchoalveolar lavage - HLA-DR human leukocyte antigen-DR - IL-2 interleukin-2 - NSCLC non small cell lung cancer - SCLC small cell lung cancer - TF transferrin - VLA-1 very late antigen-1     

Eosinophilia in bronchoalveolar lavage fluid and architectural destruction are features of desquamative interstitial pneumonia

Aims:  Desquamative interstitial pneumonia (DIP) is a rare pattern of diffuse parenchymal lung disease known to overlap with respiratory bronchiolitis-interstitial lung disease (RB-ILD). The aim was to review biopsy-proven cases of DIP to investigate further the clinical, imaging and histological features of this disease.
Methods and results:  Twenty patients fulfilled the pathological criteria: 19 men and one woman with a mean age of 54 years. Clinical features, bronchoalveolar lavage (BAL) data, radiological findings, pathological findings other than criteria, effect of therapy and outcome were examined. The BAL data for 17 cases revealed marked eosinophilia (mean 18%) and moderate neutrophilia (mean 11%). Computed tomography in 17 patients showed peripheral involvement in all cases with a clear margin in 64% and thin-walled cysts in 35% of cases. Additional pathological features were a distinct lobular distribution (70%) and architectural destruction (70%) with cyst formation (55%). Eighteen of the 19 patients (95%) improved under steroid pulse and/or oral therapy. Sixteen subjects (80%) are alive, three died of other diseases and one died of DIP 74 months after the diagnosis. Percent vital capacity increased significantly and new thin-walled cysts appeared in one case.
Conclusions:  BAL eosinophilia, lobular distribution and architectural destruction with cyst formation are characteristic features of DIP.     

Morphological and secretory properties of bronchoalveolar lavage mast cells in respiratory diseases

We have studied various functional and morphological characteristics of mast cells obtained in bronchoalveolar lavage from fifty-two patients with several lung diseases. The percentage of mast cells ranged from 0.04 to 0.6% (bronchial carcinoma). 0.05–0.3% (sarcoidosis), 0.06–0.25% (asthma), 0.04–1.8% (miscellaneous) and 0.02–0.04% (normals). There were no significant differences in the mast cell counts between the disease groups. Lung mast cells exhibited heterogeneity of size, shape and intensity of staining. Cells from thirty-seven subjects were further studied for total histamine content and histamine release using various secretagogues. There was a significant correlation (P<0.001) between the histamine content of the total lavage cell population and mast cell counts. The calculated mean histamine content per mast cell was 6.35 pg. Histamine was released in a dose-dependent fashion after stimulation with anti-IgE, calcium ionophore and phorbol myristate acetate with a time course of histamine release characteristic of the mast cell. Unlike peripheral blood basophils, no release was observed following incubation with f-met-leu-phe (10^?6-10^?8m ) and neither cell type released histamine following incubation with 48/80 (10 μg/ml). Inhibition of anti-IgE-induced histamine release was obtained following pre-incubation with salbutamol (10^?4-10^?6m ). These studies indicate that bronchoalveolar lavage is a suitable model for the study of human lung mast cells.