cVWF formation during TMA attacks in patients with TTP. (A-C) VWF antigen levels, cVWF levels, and fraction of VWF in a plasmin-cleaved state in healthy controls, patients with TTP in remission, and during acute attacks. Data represent 3 independently executed experiments and are shown as scatter plots with medians. Data were analyzed with the Kruskal-Wallis test followed by the Dunn multiple comparisons test. ∗P < .05; ∗∗∗∗P < .0001; ns, nonsignificant. (D-F) Correlations between PAP complex levels and platelet counts (D), cVWF levels and platelet counts (E), and cVWF levels and PAP complex levels (F). (G-I) Correlations between VWF antigen and cVWF levels (G), VWF antigen levels and platelet counts (H), and VWF antigen levels and PAP complex levels (I). Correlations were computed by Pearson correlation coefficients. Healthy, healthy controls.