Virucidal heat-treatment of single plasma units: a potential approach for developing countries

Since HIV first burst onto the scene of transfusion medicine, the quest for viral inactivation processes for plasma and plasma products has not ceased . Sophisticated methods for improving viral safety are currently used in th e industrial world. However, in developing countries, with no facilities fo r treating plasma, nonviral-inactivated fresh frozen plasma [FFP] continues to be used extensively, and as screening may not be optimal (or may even b e absent), FFP still contributes to the spread of HIV and other infectious viruses. The feasibility of heat-treating FFP at the liquid state, in its collection bag, was explored by testing diverse conditions of temperature and duratio n, in the presence of biologically compatible stabilisers. Quality of the h eat-treated plasma was evaluated by haematological, biochemical and animal assays. The efficiency of the method to inactivate viruses was validated us ing HIV and model viruses. The selected heating conditions are 50 degreesC for 3 h. The optimized comb ination of stabilisers is composed of 30 mM trisodium citrate, 10 g L-1 L-l ysine, 12 mM calcium gluconate and 150 g L-1 sorbitol. Plasma coagulability is appropriately preserved as shown by the KCT ratio (1.4). Recovery of bi ological activity of most coagulation factors is higher than 70% (including fibrinogen Sc von Willebrand factor). Electrophoretic and immunoblotting s tudies did not evidence protein aggregation and/or degradation. Viral valid ation studies of this procedure have shown complete inactivation of HIV (> 6.6 log) in less than 1 h of treatment. A viral reduction of at least 4 log for various model viruses, including those of hepatitis A and C viruses, s uggests a potential contribution of the method to diminish the risk from va rious blood-borne viruses. The selected formulation appears to preserve plasma protein integrity and p roperties. The procedure does not require sophisticated equipment but it is mandatory to monitor it carefully to ensure quality and reproducibility. I f properly controlled and standardized, this approach offers an opportunity to reduce the risk of transmission of HIV and other viruses, particularly in poor countries with a high incidence of HIV.