Plasmapheresis in patients with disseminated cancer: Clinical results and correlation with changes in serum protein. The concept of “nonspecific blocking factors”

Abstract

Following reports by us and by others of elevated levels of a wide variety of globulin fractions in cancer patients and the possible immunodepressive properties of these fractions plasmapheresis was undertaken in 27 patients including 24 disseminated cases with evaluable disease (one of whom died of a pulmonary embolism after the second plasma exchange procedure), 2 post‐operative cases and 1 patient in complete remission following chemotherapy. The purpose of this procedure was to remove these “nonspecific blocking factors” from patients' sera. A number of serum protein fractions were assayed prior to and following the plasma exchange procedure and an attempt was made to correlate the modifications observed with clinical findings. Surprisingly, 8 of 23 evaluable patients (4 breast, 2 colon, 1 thyroid and 1 melanoma) showed a partial objective response which was documented 2 to 3 weeks after the first plasmapheresis. The procedure was well tolerated considering the advanced nature of the patients. Urticarial, hypotensive, and hypocalcemic reactions occurring during plasma exchange were managed without much difficulty. More serious was the development of viral hepatitis as a late complication with one fatality among 3 cases. Pre‐ and post‐plasmapheresis assays for various protein fractions revealed a decrease in all the factors studied, the drop being statistically significant for alpha 2, běta and gamma globulins, haptoglobin, IgG and IgM. Comparison of changes in clinical responders and nonresponders showed a relatively more marked decrease in the former group for alpha 1 and alpha 2 globulins, alpha 1 antitrypsin, haptoglobin, orosomucoid, IgA and IgM, although the difference was not statistically significant, owing to the small numbers involved. It is suggested that the clinical findings in this study can be attributed to the removal from patients' sera of “blocking factors” including certain nonspecific acute phase reactants and also possibly immune complexes that were not investigated in this study Cancer 40:3146‐3154, 1977. Copyright © 1977 American Cancer Society