title: Increased levels of interleukin-6 are associated with lymphocytosis in bronchoalveolar lavage fluids of idiopathic nonspecific interstitial pneumonia.
abstract: Local overexpression of interleukin-6 (IL-6) experimentally induces lymphocytic infiltration in the bronchial tree of rat. Among idiopathic interstitial pneumonia (IIP), nonspecific interstitial pneumonia/fibrosis (NSIP) has an increased number of lymphocytes in bronchoalveolar lavage (BAL) fluid when compared with usual interstitial pneumonia (UIP). To reveal a relation of IL-6 with the lymphocyte infiltration of NSIP, IL-6 was measured in BAL fluids of idiopathic NSIP (n = 7), idiopathic UIP (n = 16), and normal control subjects (n = 45). IL-6-producing sites were assessed by IL-6 protein stain on biopsy specimens of NSIP, UIP, and normal lung of mediastinal tumors. Lymphocyte numbers and IL-6 levels in BAL fluids were higher in NSIP than those in UIP (p < 0.01, respectively), which were also higher when compared with those of normal control subjects (p < 0.01, respectively). In NSIP, the levels of IL-6 correlated with the number of lymphocytes (r = 0.93, p < 0.01). UIP cases were divided into two groups: high-UIP (n = 7) or low-UIP (n = 9) according to IL-6 levels greater than or within the 95 percentile of normal control subjects, respectively. The high-UIP group had BAL lymphocytosis when compared with the low-UIP group (p < 0.05). IL-6 stained on epithelial cells of the bronchial tree and on alveolar macrophages of NSIP and UIP. In conclusion, the lymphocytosis in BAL fluid of patients with NSIP and a subgroup of UIP is associated with the high levels of IL-6 and its sources are the epithelial cells of the small airway and the alveolar macrophages.
authors.affiliation: Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Radiology, and Anatomic Pathology, Soonchunhyang University Hospital, Seoul, Korea.
authors.forename: C S
authors.initials: CS
authors.lastname: Park
authors.forename: S W
authors.initials: SW
authors.lastname: Chung
authors.forename: S Y
authors.initials: SY
authors.lastname: Ki
authors.forename: G I
authors.initials: GI
authors.lastname: Lim
authors.forename: S T
authors.initials: ST
authors.lastname: Uh
authors.forename: Y H
authors.initials: YH
authors.lastname: Kim
authors.forename: D I
authors.initials: DI
authors.lastname: Choi
authors.forename: J S
authors.initials: JS
authors.lastname: Park
authors.forename: D W
authors.initials: DW
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Kitaichi
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D004847:Epithelial Cells / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D008168:Lung / Q000276:immunology / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D008218:Lymphocytosis / Q000276:immunology* / Q000473:pathology; D016676:Macrophages, Alveolar / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D051381:Rats; D012016:Reference Values
chemical_list: D015850:Interleukin-6