ADAMTS-13 levels in fresh, stored, and solvent detergent treated plasma

Abstract

Background ADAMTS-13 is implicated in the pathophysiology of thrombotic thrombocytopenic purpura (TTP). Plasma exchange is thought to be effective through removal of a harmful substance or provision of a required material such as ADAMTS-13. As various methods are used to prepare plasma we determined the effects of storage and solvent detergent treatment on the ADAMTS-13 levels in plasma. Methods Samples from fresh plasma and fresh frozen plasma (FFP) were stored at 22 °C and ADAMTS-13 levels were measured at 0, 12, 24, 48 and 72 h. Samples were also taken from solvent detergent treated plasma (SDP) and cryosupernatant plasma (CSP). Total protein, albumin, fibrinogen and immunoglobulins were also measured. Results In fresh plasma, the levels of both the 175 and 140 Kd subunits of von Willebrand factor were consistent at 1.38 and 1.35 OD units from 0 to 48 h indicating normal ADAMTS-13 activity. The Vitex SDP produced slightly more of the 140 Kd subunit than did Octapharma SDP which gave equivalent fragments. Cryosupernatant plasma was the same as normal plasma. None of these values changed over 48 h. There was a 28% decrease in FVIII in fresh plasma over 24 h. Fibrinogen and albumin were unchanged. Conclusion ADAMTS-13 levels are not significantly decreased by storage of plasma at room temperature for up to 48 h. Both CSP and SDP also contained essentially normal levels of ADAMTS-13 and therefore could be used for treatment of patients with TTP.