Popis: |
The past lustrum has witnessed rapid progress in all technical aspects of membrane-moderated plasmapheresis. The underlying transport theory has advanced from crude phenomenology to sophisticated quantitative mathematical modeling. Correspondingly, plasma filters have become more effective, smaller, and cheaper. Membrane-based, closed loop plasmapheresis, in which endogenous albumin is returned to the patient while pathogens are discarded, is already practical for certain disease categories, i. e. those mediated by cryoprecipitates or IgM sized pathogens. Further process optimization and the use of more specific membranes will certainly extend the range of application of cascade- and cryo-filtration. Specific or non-specific immunoadsorption represent the ultimate in closed-loop methodology, but formidable problems remain to be solved in the areas of cost, capacity, stability, toxicitiy, antigen-leaching, and sterilization. When such sorbents are produced in a form suitable for direct contact with blood, the loop will indeed be closed; membrane filters will no longer be necessary for therapeutic plasmapheresis but should be enjoying widespread utility in the donor-plasmapheresis applications for which they were originally targeted. |