Fig. 1.

Anti-A549 cell autoAbs in SARS patient sera. Human A549 epithelial cells were incubated with a 1 : 20 dilution of sera from SARS patients with different days of fever onset (n = 140), non-SARS-pneumonia patients (n = 8), or healthy controls (n = 10), followed by FITC-conjugated anti-human IgG, IgM, or IgA, and then observed by fluorescent microscopy (a) or analysed by flow cytometry (b). The percentages of A549 cells that reacted with patient or control sera are shown.