Autoantibodies against human epithelial cells and endothelial cells after severe acute respiratory syndrome (SARS)-associated coronavirus infection.

The severe acute respiratory syndrome (SARS) is caused by infection with the SARS-associated coronavirus (SARS-CoV) and characterized by severe pulmonary inflammation and fibrosis. In this study, 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 month after the disease onset: phase II/phase III) were investigated. Antibodies in sera of patients and 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 cell-based ELISA and indirect immunofluorescence staining. The results 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. Sera from SARS patients at phase II/phase III could mediate complement dependent cytotoxicity against some A549 cells and HPEC. 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 post-infectious cellular injury and also induce SARS-induced immunopathology. (c) 2005 Wiley-Liss, Inc.