title: Clinical significance of interleukin 33 (IL-33) in patients with eosinophilic pneumonia.
abstract: BACKGROUND
  Interleukin 33 (IL-33) works as a functional mediator in allergic disease by enhancing the activity of eosinophils and inducing expression of T helper 2 (Th2)-associated cytokines. However, the role of IL-33 in pulmonary eosinophilia has not been elucidated. We investigated the levels of IL-33 in eosinophilic pneumonia (EP) together with associated cytokines, and discussed the clinical significance of IL-33 in EP.
  
  
  METHODS
  Sera and bronchoalveolar lavage fluid (BALF) were obtained from 16 patients with EP, including acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP). Twelve patients with acute respiratory distress syndrome (ARDS) were also included for comparison. The concentration of IL-33 and Th2 cytokines (IL-4, IL-5, IL-13) were measured by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The concentration of serum IL-33 was significantly higher in patients with AEP than in CEP. In CEP, only patients with atopic factors showed mild increase of serum IL-33. The concentration of BALF IL-33 was also significantly elevated in AEP, however, it remained quite low in CEP. Among Th2 cytokines, IL-5 was significantly increased in both serum and BALF in AEP, and the level of IL-5 was positively correlated with that of IL-33. ARDS showed no increase of serum and BALF IL-33.
  
  
  CONCLUSIONS
  The remarkable increase of BALF IL-33 in AEP indicated the local production of IL-33 in lungs. IL-33 is considered to be a local key molecule for triggering pulmonary eosinophilia, together with IL-5. BALF IL-33 appears to be a useful marker for discriminating AEP from CEP and ARDS.
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Jichi Medical University, Tochigi, Japan. naoko.m@jichi.ac.jp
authors.forename: Naoko
authors.initials: N
authors.lastname: Mato
authors.forename: Masashi
authors.initials: M
authors.lastname: Bando
authors.forename: Aya
authors.initials: A
authors.lastname: Kusano
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Hirano
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakayama
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Uto
authors.forename: Takakiyo
authors.initials: T
authors.lastname: Nakaya
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamasawa
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Sugiyama
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000276:immunology; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D000067596:Interleukin-33; D007378:Interleukins / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011657:Pulmonary Eosinophilia / Q000276:immunology* / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D016207:Cytokines; C506536:IL33 protein, human; D000067596:Interleukin-33; D007378:Interleukins; D007073:Immunoglobulin E