Solvent/detergent-treated plasma has decreased antitrypsin activity and absent antiplasmin activity

Solvent/detergent (S/D)-treated plasma is currently marketed by the American Red Cross as a virally inactivated alternative to fresh-frozen plasma (FFP). The serpin-type serine proteinase inhibitors have a flexible reactive site loop (RSL) that can convert from the active conformation to the inactive latent or polymerized conformations when exposed to heat and/or detergents. We have compared the conformational stability and inhibitory activity of 3 plasma serpins-antithrombin, antitrypsin, and antiplasmin-in S/D plasma and FFP. In S/D plasma, virtually 100% of the antiplasmin and approximately 50% of the antitrypsin are in either the latent or polymerized conformation and lack inhibitory activity, while in FFP only the active conformation is present. Interestingly, antithrombin is not affected by S/D treatment and remains fully active. These data demonstrate that S/D plasma is not simply a virally inactivated equivalent of FFP. The lack of antiplasmin activity and decreased antitrypsin activity in S/D plasma suggest that it may not be as effective as FFP for the treatment of bleeding in patients with systemic activation of proteolytic cascades, such as disseminated intravascular coagulation and sepsis, acquired fibrinolytic states, and large-volume transfusion. Although there has been extensive use of S/D plasma in several European countries with no reports of adverse effects, clinical studies directly comparing the efficacy of these 2 plasma products are needed to directly evaluate the relative therapeutic efficacy of FFP and S/D plasma for the treatment of these diseases.