Therapeutic apheresis in malignancy.

Plasmapheresis (PP), staphylococcal protein A immunoadsorption (SPI), and extracorporeal photochemotherapy (EP) have been utilized in cancer treatment for about 20 years. PP removes immune complexes and induces a temporary increase in T4/T8 ratio, natural killer cell activity, and blastogenic responses. SPI removes immune complexes, enhances lymphocytic responses, and activates complement. EP increases lysis of circulating lymphoma cells by CD8+ cytotoxic T cells and increases tumor necrosis factor production by host monocytes. PP induces partial remission in about 28% of patients, but this remission is short lived. SPI gives similar results. Addition of PP to chemotherapy has been reported to prolong survival in patients with multiple myeloma. EP appears useful in treating cutaneous T cell lymphomas with 25% of patients achieving complete response and 50% of patients attaining partial remission. Thus, PP and SPI induce short-lived immune responses, but have no proven clinical utility. EP may be useful in the treatment of cutaneous T cell lymphomas.