Immunotherapy in liver tumours: I. Combined administration of recombinant interleukin-2 (IL-2) and interferon-alpha through the subcutaneous transposed spleen prolongs the half-life of IL-2 in vivo and enhances antitumor effects.

Two modifications in this study, including the use of subcutaneous transposed spleen (STS) as a port for administration of recombinant interleukin-2 (IL-2) and interferon-alpha (IFN-alpha), and the mixture of IL-2 and IFN-alpha with degradable starch microspheres (IIM), for the treatment of rat liver tumor are introduced. Group I is the control. Group II received the IIM schedule through the STS. Group III and group IV received IL-2 and IFN-alpha, diluted with normal saline and injected through the STS or a peripheral vein. The comparative studies indicated that the best result was seen in group II where the elevated concentration of IL-2 in portal blood and massive tumor necrosis with lysis were observed. Inhibitions of tumor growth of 33%, 20% and 13% in group II, III, and IV, respectively, were observed. We conclude that administration of the IIM schedule through the STS is an effective method for the treatment of liver tumor in rats.