[The association of von Willebrand factor and von Willebrand factor-cleaving protease in systemic lupus erythematosus].

OBJECTIVE

To evaluate the clinical significance of plasma von Willebrand factor (vWF) and von Willebrand factor-cleaving protease (vWF-CP) activity in systemic lupus erythematosus (SLE).

METHODS

vWF antigen (vWF:Ag) and vWF-CP activity were respectively evaluated by using ELISA and residual-collagen binding assay (R-CBA) in 30 patients with SLE and 40 normal controls.

RESULTS

The level of the vWF:Ag in SLE patients (114.6 +/- 16.3)% was significantly higher than that in the normal controls (71.3 +/- 49.5)% (P < 0.01), while the level of plasma vWF-CP activity in the SLE patients (57.7 +/- 16.3)% was significantly lower than that in the controls (86.6 +/- 1.8)% (P < 0.01). The level of vWF-CP activity was positively correlated with SLE disease activity index (SLEDAI). The alterations of these two indices were remarkable in lupus nephritis (LN) patients in comparison with those in non-LN patients. The level of vWF-CP activity in type IV LN was lowest among the four types of LN (II, III, IV, V). The level of the vWF:Ag in 30 SLE patients was reduced four weeks after therapy, on the other hand, the vWF-CP activity was significantly increased in those with SLEDAI below 9, but unchanged in whose with SLEDAI above 9.

CONCLUSIONS

The injury of endothelial cells and to production autoantibodies against vWF-CP were the factors that resulted in lower vWF-CP activity in SLE patients and this lowered activity may influence the progression of SLE.