嚴重急性呼吸道症候群的免疫致病機轉─（子計畫四）SARS病人抗肺部組織及細胞自體抗體之偵測

The severe acute respiratory syndrome (SARS), an atypical pneumonia emerged in
21st century, is caused by the invasion of the SARS-associated coronavirus
(SARS-CoV) and characterized by severe pulmonary inflammation and fibrosis. In
this study, we investigate the possibilities of the development of autoantibodies
against human epithelial cells and endothelial cells in patients with SARS at different
time periods (the first week: phase I, 1-2 months after the disease onset: phase
II/phase III). Antibodies in sera of patients and normal healthy controls against 1)
A549 human pulmonary epithelial cell-line, 2) human umbilical venous endothelial
cells (HUVEC), 3) primary human pulmonary endothelial cells (HPEC) were detected
by the methods of cell-based ELISA, indirect immunofluorescence staining, and flow
cytometry. The results of ELISA revealed that serum levels of IgG anti-A549 cells
antibodies, IgG anti-HUVEC antibodies, and IgM anti-HPEC antibodies were
significantly higher in SARS patients at phase II/phase III than those in healthy
controls. Results of the other two tests, indirect immunofluorescence staining and
flow cytometry, were consistent with the previous one. Sera from SARS patients at
phase II/phase III could mediate complement dependent cytotoxicity against A549
cells. It is concluded that some autoantibodies against human epithelial cells and
endothelial cells would be developed after SARS-CoV infection and this phenomenon
may indicate the post-infectious cellular injury and also provide the possibility of
SARS-induced immunopathology.
III