Nanofiltration of single plasma donations: feasibility study

Major technical developments have been made in recent years to improve the quality and safety of human plasma for transfusion and fractionation. The present study was performed to assess, for the first time, the feasibility of applying a nanofiltration process, using 75-nm and 35-nm mean pore size membranes (Planova) 75N and Planova 35N), to human plasma.

Ten apheresis plasma units were obtained from 10 plasma donors. Within 4 h of collection, plasma was subjected to leucoreduction and filtration (using 75-nm and 35-nm mean pore size membranes) at 35 degrees C, at less than 1 bar pressure. Aliquots of plasma were taken at all steps of the filtration procedure and numerous plasma quality parameters were measured. In addition, six hepatitis C virus (HCV)-positive plasma donations were experimentally subjected to the same filtration sequence and subsequently assessed by RNA polymerase chain reaction (PCR) and branched-chain DNA-quantification assays.

Leucoreduced plasma can be reproducibly nanofiltered onto a sequence of 75-nm and 35-nm membranes, at a flow rate of 450 ml/h and a temperature of 35 +/- 0.5 degrees C. Some protein dilution, or loss, was found during filtration, but the plasma filtered through membranes with a mean pore size of 75 nm and 35 nm met in vitro specifications for use in transfusion or fractionation. There were no signs of activation of the coagulation system. HCV-positive plasma donations became negative, as judged by PCR and branched-chain DNA assay results, after filtration through the 35-nm membrane.

It is possible to apply a 75 + 35-nm filtration process to leucoreduced human plasma. This technology may have important future benefits in improving the quality and safety of plasma, by removing blood cell debris and infectious agents.