A minipool process for solvent-detergent treatment of cryoprecipitate at blood centres using a disposable bag system

Single-donor or small-pool cryoprecipitates are produced by blood establishments, mostly in developing countries, for substitute therapy in haemophilia A, von Willebrand disease and fibrinogen deficiency, as well as for the manufacture of fibrin sealant. As cryoprecipitate may be contaminated with pathogenic plasma-borne viruses, there is an urgent need to develop a simple method for the viral inactivation of cryoprecipitate.

Cryoprecipitate was obtained according to standard procedures. Ten minipools of five or six donations of cryoprecipitate were prepared and subjected, in sterile closed bags, to a viral inactivation treatment using either 2% tri(n-)butyl phosphate (TnBP) for 4 h at 37 degrees C or the combination of 1% TnBP and 1% Triton X-45 for 4 h at 31 degrees C. The cryoprecipitates were subsequently extracted three times in their processing bags by mixing and decantation using 7.5% sterile ricinus oil. The TnBP-treated cryoprecipitates were further subjected to a clarifying centrifugation step at 3800 g for 30 min. The final products were dispensed into individual bags and frozen at -30 degrees C or lower.

The cryoprecipitates treated with either 2% TnBP or 1% TnBP + 1% Triton X-45 showed excellent (> 93%) mean recovery of coagulant factor VIII (FVIII), ristocetin cofactor Von Willebrand factor (VWF:RCo), and clottable fibrinogen activity. Prothrombin time, international normalized ratio and activated partial thromboplastin time increased during solvent-detergent treatment but returned to initial values after oil extractions. The final content of TnBP and Triton X-45 was < 10 and 50 ppm, indicating excellent removal by the oil-extraction procedure.

Viral inactivation treatment by TnBP, with or without Triton X-45, can be applied to minipools of cryoprecipitate, with good recovery of FVIII, VWF and fibrinogen. The viral inactivation and solvent-detergent removal process can be performed in a closed bag system and using simple blood establishment techniques and equipment. This technology could be considered for the improved viral safety of cryoprecipitate which is used to treat haemophilia A, von Willebrand disease or fibrinogen deficiency, or to prepare fibrin sealant.