Selective Removal of Immunosuppressive factors by Double Filtration Plasmapheresis in Cancer Patients

Abstract

In order to remove selectively various immunosuppressive factors present in sera of cancer patient, DFPP was performed in 11 patients. Two types of membrane filters, the 1st filter with a porosity of 0.2μ and the 2nd filter of 0.02μ, were used for DFPP. About 2500ml of plasma obtained by the 1st filter were separated by the 2nd filter into 250ml of the discard fluid and the 2nd filtrate which was returned to the patient. The discard fluid showed the strongest inhibitory effect on normal lymphocyte blastogenesis to PHA and the 2nd filtrate the lowest. The PHA inhibitory effect of patient sera was clearly decreased (%inhibition; 40.4% to 23.7%) after DFPP. The reduction rates of CEA, ferritin and immunosuppressive substance were 39%, 82% and 14% respectively. PPD skin test improved in 71% patients (5/7) and performance status remarkably improved in 45% (5/11). The results suggest that immunosuppressive factors, especially those of present in the high molecular weight protein fractions, can be removed selectively without large amount of replacement fluid by DFPP.