title: [A histopathological study on Influenza A H1N1 infection in humans].
abstract: OBJECTIVE
  To find histopathological changes on major organs of Influenza A H1N1-infected patients and its relationship to clinical symptoms.
  
  
  METHODS
  The autopsies were performed following conventional protocols and strict safety procedures. Tissue samples from all major organs of three cases were collected and fixed in 4% formalin. The histopathological changes on these samples were observed under a light microscope.
  
  
  RESULTS
  The lungs of some damaged areas of three cases showed diffuse alveolar damage (DAD) with hyaline membranes formation and intra-alveolar edema and/or fibrin. Most areas of the lungs in the three cases showed necrotizing bronchiolitis, hemorrhage, secondary infection, thrombosis and focal alveolar necrosis. The lungs exhibited proliferation of pneumocytes and fibrosis of the interstitium in one case. In one case, the brain showed focal hemorrhage and focal liquefactive necrosis. In one case, the heart showed edema.
  
  
  CONCLUSIONS
  The respiratory tract is the major target of influenza A H1N1 virus. The changes of DAD with secondary infection in the lung resulted in hypoxia, leading to multiple organ failure and death.
authors.affiliation: Department of Pathology, Peking University School of Basic Medical Sciences, and Tibet Autonomous Region People's Hospital, Beijing 100191, China.
authors.forename: Yao-xin
authors.initials: YX
authors.lastname: He
authors.forename: Zi-fen
authors.initials: ZF
authors.lastname: Gao
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.forename: Guan-jie
authors.initials: GJ
authors.lastname: Sui
authors.forename: Guang-wei
authors.initials: GW
authors.lastname: Ran
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Xi-shun
authors.initials: XS
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D001344:Autopsy; D001980:Bronchi / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification; D007251:Influenza, Human / Q000473:pathology*; D008168:Lung / Q000473:pathology*; D008297:Male