Separation of albumin from autologous plasma by heat

Separation of IgG and IgM from albumin in citrated human plasma using electrodialysis and metal ion affinity precipitation

Plasmapheresis is the process by which plasma is separated from whole blood for therapeutic purposes. The primary reason to perform plasmapheresis is to remove immunoglobulins and not to necessarily remove the remainder of the plasma proteins. Nevertheless, most plasmapheresis is performed by centrifugal separation to remove bulk plasma. We have investigated whether electrodialysis and metal ion affinity precipitation can be used to selectively remove immunoglobulins from citrated plasma and potentially serve as an adjunctive technique to centrifugal plasmapheresis. Using a commercial electrodialysis device, we have desalted citrated plasma to separate immunoglobulins from albumin, and have determined the effects of pH adjustment and addition of zinc acetate for concomitant metal ion affinity precipitation. With desalted pH adjusted citrated plasma containing 1.5 mM zinc acetate, we achieved more than 80% recovery of albumin with removal of almost 60% of the immunoglobulin (Ig)G. Almost 80% of polyclonal IgM and 90% of monoclonal IgM was also removed. IgA was not effectively removed under any of the conditions tested. Selective precipitation with electrodialysis and zinc acetate precipitation appears to be an effective technique for the separation of IgG and IgM from albumin in citrated plasma.