Cleavage of GST-VWF73-H by patients' plasma. GST-VWF73-H was incubated with serially diluted normal plasma (0%-100%) or with plasma from patients with USS, ticlopidine-associated TTP (Tc-TTP), idiopathic TTP, and HUS. The band intensities of reaction products were measured by chemiluminescence on Western blot, and the relative activities of patients' plasma (%, shown by italic numbers) to normal plasma were calculated from nonlinear regression by serially diluted normal plasma. USS patients 1 to 3 correspond to ST-III-4, SY-III-1, and KI-III-2 by previous report.²  Tc-TTP patients 1 and 2 were reported by Sugio et al³⁵  and Orimo et al,³⁶  respectively. The idiopathic TTP patients 1 to 9 correspond to the case numbers 1-3, 5, 6, 11-13, and 17, and HUS patients 1 to 4 correspond to the case numbers 2, 4, 6, and 9 in the previous report.³⁷