PAI-1 antigen levels at onset of bilirubin increase after BMT (n = 31). As bilirubin levels began to increase (<3 mg/dL), PAI-1 antigen (mean ± SD) was found to be significantly elevated in patients with VOD (321.6 ± 161.2 ng/mL) as compared with patients with GVHD (22.8 ± 8.4 ng/mL; P < .001) or with other liver damage (32.8 ± 30.8 ng/mL; P = .0001). (⋄) Diagnosis by clinical criteria only; (♦) diagnosis confirmed histologically.