Fig. 4.

Tissue factor (TF) release by seronegative anti-phospholipid syndrome (SN-APS) immunoglobulin (Ig)G fraction. Cells were stimulated with normal human serum IgG (NHS-IgG) (200 µg/ml), SN-APS IgG (200 µg/ml), lipopolysaccharide (LPS) (100 ng/ml), APS IgG (200 µg/ml), cardiolipin (CL)-adsorbed SN-APS IgG or lyso(bis)phosphatidic acid antibodies (LBPA)-adsorbed SN-APS IgG, for 4 h at 37°C. After treatment, the supernatants were collected and analysed using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Results are expressed as mean ± standard deviation from three different experiments. SN-APS versus control (unstimulated cells) P < 0·05, SN-APS versus normal IgG (P < 0·05).