Plasma MPO correlated with DNA levels in TTP patients during therapy. Patient samples and DNA levels are identical to those in Figure 2. MPO levels were quantified, plotted as fold increase over MPO levels of healthy control samples, and compared with plasma DNA. DNA and MPO levels follow similar kinetics in all patients. (¹The x-axis not linearly formatted. Data shown are from consecutive plasma samples and the time between plasma sample collections varies. ²Rituximab was given 4 times at weekly intervals.)