Effects of ex-vivo plasma adsorption over protein A sepharose in acute leukemia.

Plasma adsorption over immobilized Staphylococcus aureus Cowan I has resulted in tumor regression in several animal and human trials. Protein A, because of its ability to bind IgGs has been considered as the effective component of Staphylococcus aureus. In 4 patients with acute leukemia, a plasma volume of 1500 cm3 was passed in an ex-vivo system over immobilized SpA-Sepharose and then reinfused. Almost all of the IgGs contained in the plasma volume could thus be removed. Toxic side-effects were mild. No significant clinical improvement could be obtained. Plasma incubation with SpA did not modify blast cell viability or leukemic progenitor cell growth. Along with others, this study shows that Protein A is probably not the mediator of the tumoricidal responses observed in studies using adsorption over Staphylococcus aureus Cowan I. The ex-vivo system prepared for this study could also be used for plasma IgG removal for the treatment of autoimmune or immune-complex related disorders.