Intensive plasma exchange on the cell separator: effects on serum immunoglobulins and complement components.

Abstract

Six patients with IgG myeloma and four patients with glomerulonephritis underwent a course of intensive plasma exchange on a continuous flow cell separator. Immunoglobulin‐free and complement‐free replacement fluids were used in each 4.0 or 5.2 l. exchange. The concentrations of the serum immunoglobulins IgG, IgA and IgM, total haemolytic complement (CH50) and the complement components C3 and C4 were measured immediately before and after each exchange. The efficiency of an individual plasma exchange varied from a mean reduction in CH50 and IgA to 47.5% and 47.8% respectively of their initial level to a corresponding reduction of C3 concentration to 37.2%. Consecutive daily plasma exchange further decreased the serum levels of all these factors. All factors except CH50 were reduced to less than 30% after the fifth and less than 10% after the tenth exchange. Although daily exchanges were necessary to maintain reductions in serum C3 and C4 concentrations, subnormal immunoglobulin concentrations could be maintained with alternate daily exchanges. The effect of concurrent immunosuppressive therapy could be assessed in one patient. A significant reduction in the rate of recovery of serum IgG and IgA concentrations was demonstrated during immuno‐suppressive therapy. Although the therapeutic effectiveness of sustained reduction of these proteins is unproven, our data have important implications for the organization, cost and workload involved in programmes of intensive plasma exchange.