Ex vivo perfusion of plasma over protein A columns in human mammary adenocarcinoma. Role of the Fc-binding capacity of protein A in the side effects and the tumoricidal response.

Plasma of twelve patients presenting with a metastic mammary adenocarcinoma was perfused ex vivo over columns of protein A covalently linked to crystalline silica. The plasma of seven patients (group A) was perfused over columns of protein A exhibiting a normal Fc-binding capacity and the plasma of five (group B) over columns of protein A in which the Fc-binding capacity was destroyed. In group A, all patients experienced acute, easily manageable, side effects (hypotension, chills, mild fever, leucocytosis and pain in tumour sites) during or immediately after the immunoadsorption procedures, and three exhibited an objective partial regression after two to five sessions. In contrast, none of the patients from group B developed any acute side effects and all showed evident progression of their disease during the treatment. Tumour cells in all stages of destruction, sometimes surrounded by extensive fibrosis, were seen in biopsies of patients A. However, focal areas of active tumour proliferation were always present in these patients. These data confirm that ex vivo perfusion over protein A columns of plasma from patients with cancer can induce a tumoricidal response in some instances and show that the Fc-binding capacity of protein A is most probably responsible for the necrolytic response and the side effects.