CRYOSUPERNATANT AS REPLACEMENT FLUID FOR PLASMA-EXCHANGE IN THROMBOTIC THROMBOCYTOPENIC PURPURA

The current established treatment of thrombotic thrombocytopenic purpu ra (TTP) is plasma exchange with fresh frozen plasma (FFP). With this treatment, there is a 49% response after seven exchanges and a 78% sur vival at 1 month. Although the exact cause of TTP is unknown, the pres ence of non Willebrand factor (VWF) multimers has been implicated in t he disease. Accordingly, it has been suggested that cryosupernatant (p lasma from which cryoprecipitate has been removed), which is relativel y deficient in VWF multimers, might be an effective replacement fluid during plasma exchange. Patients from six centres were treated by plas ma exchange with cryosupernatant. 18 patients who had failed a first c ourse (average 7.7 exchanges) of plasma exchange with FFP, received a further seven exchanges with cryosupernatant. Subsequently, 40 previou sly untreated patients were exchanged with cryosupernatant. Of the 18 previously treated patients, 11 responded (defined as an increase in p latelet count to > 150 x 10(9)/l and no neurological events) after sev en exchanges and 15 (83%) of the patients were alive at 1 month. The r esponse rate in the 40 previously untreated patients was 75% at the en d of seven exchanges and 95% of the patients were alive at 1 month. Th ese values are significantly different (P < 0.05) from those reported in our earlier study and in other patients concurrently treated at the same centres with FFP when cryosupernatant was not available. Some pa tients who have failed to respond to plasma exchange with FFP replacem ent will respond to further exchange with cryosupernatant. Cryosuperna tant replacement may be more effective as first-line treatment of TTP than FFP.