A general extracorporeal immunoadsorption method to increase tumor-to-tissue ratio.

The idea of applying extracorporeal immunoadsorption (ECIA) in radioimmunodiagnosis and radioimmunotherapy has been proposed previously. The authors here report on the development of new concept using a general method for ECIA based on biotinylated MoAb adsorbed on an avidin column. Athymic rats heterotransplanted with either human melanomas or human lung carcinoma were injected with iodine-125-labeled biotinylated 96.5 or L6 MoAb, respectively. At 24 or 48 hours after the injection, ECIA was performed by pumping blood through a hollow-fiber plasma filter. The separated plasma then was passed through an absorbent (avidin-agarose) column. The whole ECIA procedure lasted for 3 hours. By this ECIA method, the tumor-to-normal tissue ratios were increased in various tissues (i.e., radiosensitive and blood rich organs) by a factor of four to five.