Influence of methylene blue photoinactivation treatment on coagulation factors from fresh frozen plasma, cryoprecipitates and cryosupernatants.

OBJECTIVE

To study the influence of virus photoinactivation with methylene blue (MB) on the coagulation factors of fresh frozen plasma (FFP) and the corresponding cryoprecipitates and cryosupernatants derived from it.

MATERIALS AND METHODS

The photoinactivation procedure of the German Red Cross (Springe) was applied using Biomat (Grifols, Spain). Twenty isogroup pools of three plasma units were made from 60 U of FFP. The pools were split into three bags. One of them was photoinactivated, and pre- and postinactivation samples (MB-plasma) were obtained. The second bag was treated in the same way, followed by the preparation of MB-cryoprecipitate and MB-cryosupernatant. The third bag was not photoinactivated, and was processed in the same way to obtain control cryoprecipitate and cryosupernatant. The prothrombin time and activated partial thromboplastin time were analysed, as well as fibrinogen, factors (F) II, V, VII, VIII, IX, XI and XIII, antithrombin III, von Willebrand (vW) F:RCo, vWF:Ag and the multimeric structure of vWF.

RESULTS

In plasma, the proteins most sensitive to photoinactivation were fibrinogen, FV, FVIII, FIX and FXI (24, 32, 28, 23 and 27% loss, respectively). In the MB-cryoprecipitate, the losses were higher for FVIII (23%), moderate for fibrinogen, FXIII and vWF:RCo (18, 14 and 13%, respectively) and minimal (only 3%) for vWF:Ag. In MB-cryosupernatants, the losses were higher for FV (26%) and moderate for fibrinogen (16%), FIX (18%) and FXI (19%), as well as for FII and FXIII (15%). The multimeric structure of vWF was not modified in MB-plasma or in MB-cryoprecipitates. The supernatants (both MB treated as well as controls) showed an absence of multimers of very high and high molecular weight.

CONCLUSIONS

The quantitative and qualitative conservation of coagulation factors achieved in MB-plasma-derived products suggest that they are useful for the global replacement of coagulation factors and for deficiencies in FV and FXI. In countries lacking the economic resources to obtain virally inactivated concentrates, MB-cryoprecipitates could be useful in von Willebrand's disease and fibrinogen and FXIII deficiencies. MB-cryosupernatants could be employed in thrombotic thrombocytopenic purpura, in the correction of total or partial deficiencies of prothrombin complex factors and in specific deficiencies of FV and FXI.