Patient IgG-prothrombin complex does not convert¹²⁵I-fibrinogen to ¹²⁵I-fibrin.

Nonlabeled (30 μM) and 300 nM ¹²⁵I-fibrinogen were incubated with a mixture of 750 μg/mL patient IgG and 1 μM purified prothrombin that had been preincubated at 4°C for 2 hours or with 10 NIH Us/mL α-thrombin, at 37°C for 0 to 360 minutes. Each sample was analyzed by 10% to 15% gradient SDS-PAGE under reducing conditions, followed by autoradiography.