title: Bronchoalveolar Lavage Fluid Characteristics of Patients With Sarcoidosis and Nonsarcoidosis Interstitial Lung Diseases: Ten-Year Experience of a Single Center in Turkey.
abstract: BACKGROUND
  Bronchoalveolar lavage (BAL) is a noninvasive and useful technique for evaluating interstitial lung diseases (ILDs). Flow cytometric analysis of BAL fluid reveals specific diagnostic information in some unusual ILDs, and helps to narrow down the possible causes of interstitial diseases in most patients with more common disorders. A high BAL CD4/CD8 ratio is highly specific for sarcoidosis but can also be seen in other ILDs.
  
  
  OBJECTIVE
  In this retrospective, descriptive, cross-sectional study, we compared BAL fluid characteristics and clinical variables in patients with sarcoidosis and non-sarcoidosis ILDs in a large cohort.
  
  
  METHODS
  The study was conducted in a tertiary university hospital in Zonguldak, the biggest city of the western Black Sea region of Turkey. Between 2004 and 2014, all patients who underwent both fiberoptic bronchoscopy and BAL with a suspicion of ILD were included in the study, retrospectively. Patients were divided into two main groups: sarcoidosis and non-sarcoidosis ILDs. Non-sarcoidosis ILDs were further divided into subgroups: pneumoconiosis, tuberculosis (TB), collagen vascular diseases, idiopathic interstitial pneumonias, malignancies, and unclassified ILDs. The clinical data of patients, including age, gender, smoking status, pulmonary function tests, and BAL flow cytometric analysis results, were compared among groups.
  
  
  RESULTS
  In total, 261 patients (119 sarcoidosis and 142 non-sarcoidosis ILDs) were enrolled. The median (interquartile range) BAL CD4/CD8 ratio and lymphocyte fraction were significantly higher in sarcoidosis than in non-sarcoidosis ILDs: 3.88 (3.76) versus 0.88 (1.01), respectively, and 20.6 (28.3) versus 6.0 (13.7), respectively. T cell receptor γ delta, CD16(+)56(+), CD103(+), CD8(+)103(+), and CD3(+)16(+)56(+) cells were significantly lower in sarcoidosis than in non-sarcoidosis ILDs. The median BAL CD4/CD8 ratios were significantly higher in patients with TB (1.87, P = 0.01) and malignancies (1.69, P = 0.03) than in other non-sarcoidosis ILDs.
  
  
  CONCLUSIONS
  Among BAL fluid flow cytometric parameters, CD4/CD8 and lymphocyte fraction may be helpful for distinguishing sarcoidosis from other ILDs, but they are neither specific nor diagnostic for any lung disease. Thus, a multidisciplinary diagnostic discussion is required to differentiate various ILDs.
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Tanriverdi
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Fatma
authors.initials: F
authors.lastname: Erboy
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Bulent
authors.initials: B
authors.lastname: Altinsoy
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Firat
authors.initials: F
authors.lastname: Uygur
authors.affiliation: Department of Immunology, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Arasli
authors.affiliation: Department of Immunology, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Ishak
authors.initials: I
authors.lastname: Ozel Tekin
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Muge Meltem
authors.initials: MM
authors.lastname: Tor
authors.affiliation: Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey.
authors.forename: Figen
authors.initials: F
authors.lastname: Atalay
keywords: Bronchoalveolar Lavage; CD4/CD8 Ratio; Flow Cytometry; Lung Diseases, Interstitial; Pneumoconiosis