OBJECTIVETo monitor the changes of hemolysis parameters and endothelial cell markers in thrombotic thrombocytopenic purpura (TTP) and reveal the clinical significance of these changes.

METHODSvWF-cleaving protease (vWF-CP) activity in 3 cases of TTP was detected by Western blot. The percentages of fragmented red cells (FRC) were counted throughout the entire clinical course. Levels of plasma thrombomodulin were detected by Western blot combined with density screening in TTP and healthy individuals (n = 3). Concentration of plasma VEGF was measured by enzyme-linked immunosorbent assay in TTP and healthy individuals (n = 9). Fundus fluorescein angiography was performed to search the evidence of microvascular thrombosis in one TTP patient with impaired visual acuity.

RESULTSThe lower vWF-CP activity was observed in TTP patients; the percentages of FRC in 3 cases of TTP were 1.65%, 2.50%, 3.32% respectively with an average of 2.49% at the onset of and decreased with the improvement of the disease. The levels of plasma TM and VEGF were significantly elevated in TTP than those in healthy individuals, and related to the severity of TTP. Fundus photography in one TTP patient with impaired visual acuity revealed vascular occlusion in fundus arteriole and venulae.

CONCLUSIONSA decreased vWF-CP activity is in favour of TTP diagnosis. Dynamic monitoring of plasma TM and VEGF as well as percentages of FRC are useful indexes for reflecting the severity and evaluating therapeutic response of TTP. Selective fundus fluorescein angiography is useful for the judgement of microvascular thrombosis in TTP.