Immunoblot analyses showing the domain-specific reactivity of TTP patient plasmas with different anti-ADAMTS13 inhibitor titers. Equivalent amounts of recombinant ADAMTS13 fragments were resolved on 12% SDS-PAGE and electroblotted. Plasma samples from patients 14 (32 BU/mL; panel A), 18 (6 BU/mL; panel B), 22 (10 BU/mL; panel C), and 3 (3 BU/mL; panel D) were used as sources of primary antibody and AP-conjugated antihuman immunoglobulin, and BCIP/NBT was used for visualization. Recombinant protein, lane 1: recombinant ADAMTS13 (rA-13) derived from HEK 293 cells. Purified ADAMTS13 fragments, lanes 2-7: propeptide (lane 2, I), tsp1-1 (lane 3, II), cat/dis/tsp1-1 (lane 4, III), cys-rich/spacer (lane 5, IV), tsp1/2-8 (lane 6, V), and cub1 + 2 (lane 7, VI). As a negative control, the thio/his fragment was applied (lane 8). M indicates molecular weight markers.