title: Early induction of interleukin-5 and peripheral eosinophilia in acute pneumonia in Japanese children infected by pandemic 2009 influenza A in the Tokyo area.
abstract: A novel influenza A (2009 H1N1) virus has led to a worldwide pandemic. A significant number of patients with pneumonia have been reported, although its pathogenesis remains to be elucidated. To determine its pathogenesis, we evaluated serum interleukin (IL)-5 and peripheral eosinophil counts in patients with acute pneumonia caused by the 2009 H1N1 virus. During the period from October to December 2009, 40 patients with laboratory-confirmed 2009 H1N1 pneumonia were under investigation. Their mean age at presentation was 6.8 years. The most characteristic finding was the early development of hypoxemic respiratory distress in the first 24 hr after the onset of fever. Bronchial mucous plugs included eosinophils in addition to neutrophils, even in patients without allergies. Serum IL-5 levels were elevated in 20 out of 24 patients (83%) whose samples were obtained in the first 24 hr after the onset of fever (26.5 ± 20.1 pg/mL), independent of the presence of underlying allergies. In contrast, induction of IL-5 was not documented in sera from eight patients with laboratory-confirmed 2009 H1N1 virus who developed neurological complications, but without lower respiratory infection (2.1 ± 0.7 pg/mL, P < 0.001 vs acute pneumonia). Peripheral eosinophilia was characteristic in acute pneumonia, but not in patients without a lower respiratory infection. There was a marked difference in the induction of IL-5 in 2009 H1N1 patients who developed acute pneumonia, compared with those without a lower respiratory infection. IL-5 may play a role in the early phase of acute pneumonia caused by the 2009 H1N1 virus in Japanese children.
authors.affiliation: Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, Yachiyo-shi, Chiba, Japan. mterai@tymc.twmu.ac.jp
authors.forename: Masaru
authors.initials: M
authors.lastname: Terai
authors.forename: Takafumi
authors.initials: T
authors.lastname: Honda
authors.forename: Shiho
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Masaki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Nozomi
authors.initials: N
authors.lastname: Tsuchiya
authors.forename: Yoko
authors.initials: Y
authors.lastname: Moriyama
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsui
authors.forename: Shoko
authors.initials: S
authors.lastname: Tokutake
authors.forename: Emiyu
authors.initials: E
authors.lastname: Suzuki
authors.forename: Yuri
authors.initials: Y
authors.lastname: Shirato
authors.forename: Ayako
authors.initials: A
authors.lastname: Muto
authors.forename: Kitami
authors.initials: K
authors.lastname: Hayashi
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Hamada
mesh_terms: D000208:Acute Disease; D002648:Child; D002675:Child, Preschool; D004802:Eosinophilia / Q000150:complications*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000472:pathogenicity*; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D015848:Interleukin-5 / Q000097:blood*; D058873:Pandemics; D011024:Pneumonia, Viral / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D014041:Tokyo / Q000453:epidemiology
chemical_list: D015848:Interleukin-5