The successful removal and prevention of the resynthesis of an anti-HLA antibody by plasma exchange and immunosuppression in a patient awaiting renal transplantation is described. Before treatment, the patient's serum contained a high titer (>1/50) anti-HLA antibody that reacted with 94% of our lymphocyte donor panel and produced positive cross matches with the lymphocytes from 40 cadaver kidneys. Following treatment, her anti-HLA titers fell to less than 1/10 and her sera reacted with 43% of our lymphocyte donor panel and produced negative crossmatches with lymphocytes from the first two cadaver kidney donors she was tested against. She was successfully transplanted with the second of these kidneys and is now well eight months later, with good graft function.