[Suppression of immunological response by ascitic fluid from gastrointestinal cancer patients]

Immunological analysis of ascitic fluids from 49 patients with gastrointestinal cancer was performed and compared to those from 13 patients with hepatic cirrhosis and 3 with congestive heart failure. The analysis of ascitic fluid was performed using natural killer (NK) activity, MLR, PHA-induced lymphoproliferation (LP) and PPD-LP. Immunologic suppression by malignant ascitic fluid was more remarkably observed in PHA-LP, PPD-LP, MLR and NK assay than that by cirrhotic ascites, and it was further proved to be dose dependent. Ascitic fluids from patients with congestive heart failure showed no suppressive effects. There was no correlation between these suppressions and AFP, CEA or immunosuppressive acidic protein (IAP) levels in ascitic fluids. The first fraction of sephadex G 200 Gel filtration, which has a molecular weight of more than 200,000, showed the immunosuppressive activity. It is concluded from these results that this immunosuppressive factor does not involve AFP, CEA and IAP. Thus, it is presumed that the prognosis of the patients with gastrointestinal cancer might correlate with the immunosuppressive factor in their ascitic fluid.