Therapeutic plasmapheresis and protein A immunoadsorption in malignancy: a brief review.

Plasmapheresis is being used with considerable frequency in the management of malignant and non-malignant disorders. More recently, staphylococcal Protein A immunoadsorption has been employed in similar clinical situations. In patients with malignancy, plasmapheresis has been shown to produce alterations in plasma proteins, decrease circulating immune complexes, remove "specific" and "non-specific" blocking factors, change immune reactivity, and affect monocyte function. Partial responses have been reported in a small number of patients with carcinoma of lung, colon, and breast following plasmapheresis. In addition, there are reports of favorable responses in patients with melanoma, head and neck tumors, lymphomas, leukemias, and Kaposi's sarcoma in acquired immune deficiency. All these responses were partial and brief, and the treatment did not alter the course of the disease. Plasmapheresis has been useful in the management of hyperviscosity and occasionally of paraneoplastic syndromes. It may also have a role in the treatment of thrombotic thrombocytopenic purpura associated with mitomycin-C therapy. Protein A immunoadsorption, by which circulating immune complexes are selectively removed, can activate the complement system, increase blastogenic responses, and increase the natural killer cell activity. It has been shown to produce partial responses in breast and colon cancer, as well as Kaposi's sarcoma in acquired immune deficiency. It may have a useful role to play in the management of mitomycin-C-associated thrombotic thrombocytopenic purpura. Both plasmapheresis and Protein A immunoadsorption should be considered investigational interventions at this time. Toxicity of plasmapheresis, though uncommon, can be serious and may rarely be fatal. Toxicity of Protein A immunoadsorption is mild, consisting mainly of influenza-like symptoms and rash.