F10 and systemic lupus erythematosus: Figure 3A shows that the FXa-induced clotting time was prolonged in the presence of APS-IgG at 74.2 ± 4.4 (mean ± SEM) seconds and SLE-IgG at 63.6 ± 2.7 seconds compared with 26.8 ± 0.6 seconds for HC IgG.