Plasma exchange in the treatment of immune disease.

Plasma exchange was investigated as an alternative to the use of toxic drugs to remove unwanted antibody. Studies in rabbits immunized with bovine serum albumin demonstrate that exchange transfusion after a primary immunization results in a rebound of antibody to above preexchange levels. However, exchange transfusion seven, 11, or 18 days after secondary immunization results in permanent lowering of antibody levels. Plasma exchange with the continuous flow centrifuge was used in four patients with hematologic diseases. White cell isoantibodies were removed in a septic leukopenic patient, permitting white cell transfusions. Two patients with immune thrombocytopenia were exchanges; one showed prompt and permanent elevation of platelet count, while the other did not improve. A patient with immune hemolytic anemia had stabilization of hemoglobin levels and decreased Coombs reactivity following plasma exchange.