title: [Pathologic study of circulating blood leukocytes in severe acute respiratory syndrome].
abstract: OBJECTIVE
  To study the pathologic characteristics and pathogenesis of circulating blood leucocytes infected by severe acute respiratory syndrome associated coronavirus (SARS CoV or SCV) in SARS patients.
  
  
  METHODS
  Blood samples of 22 SARS patients were studied, and 4 healthy blood samples were observed as negative controls. The white blood cells were collected from whole blood. The ultrastructural characteristics were observed by transmission electron microscopy. CD45RO antibody was used for pre-embedding immunoelectron microscopy. The SARS viral sequence was detected with real-time polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  Coronavirus-like particles were founded in the leukocytes in 6 of the 22 blood samples. Five of them gave positive results in the real-time PCR. The number of granulocytes was increased (P < 0.05) and that of lymphocytes was decreased (P < 0.05) respectively. Immunoelectron microscopy showed that CD45RO positive T lymphocyte decreased to 6% - 7%. Circulating lymphocytes had the highest percentage of infection. The morphologic characteristics of coronavirus-like particles were spherical or oval in shape, about 80 - 120 nm in diameter, with a dense round core and a clear halo around the core. A distinct membrane and club-shaped surface projections were seen in the periphery. The particles were located in the cytoplasm, the cisternae of endoplasmic reticulum, Golgi apparatus and vesicles. Virus entered cells by endocytosis or membrane fusion and was released through a budding process.
  
  
  CONCLUSIONS
  Our data suggested that lymphocytes, particularly T cells, were probably the target cells of SARS CoV. The viruses may actively infected the immune cells during SARS CoV acute infection phase and the destruction of target cells may be one of the important reasons for the death of the circulating leukocytes in SARS.
authors.affiliation: Department of Pathology, Peking University Health Science Center, Beijing 100083, China.
authors.forename: Yan-feng
authors.initials: YF
authors.lastname: Zhong
authors.forename: Xiao-ming
authors.initials: XM
authors.lastname: Gao
authors.forename: Sheng-lan
authors.initials: SL
authors.lastname: Wang
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Xie
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Wei-gang
authors.initials: WG
authors.lastname: Fang
authors.forename: Wan-zhong
authors.initials: WZ
authors.lastname: Zou
authors.forename: Xiu-lan
authors.initials: XL
authors.lastname: Li
authors.forename: Qian-ying
authors.initials: QY
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Zhen-dong
authors.initials: ZD
authors.lastname: Zhao
authors.forename: Jiang
authors.initials: J
authors.lastname: Gu
mesh_terms: D005260:Female; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes / Q000473:pathology* / Q000648:ultrastructure; D008214:Lymphocytes / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D045169:Severe Acute Respiratory Syndrome / Q000097:blood* / Q000209:etiology / Q000473:pathology